Download Special, clinical and ecological microbiology

Module 2 Special, clinical and ecological microbiology
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Text test questions
Choose faithful composition of yolk salt agar
A. *MPA, yolk, 9 % of sodium chloride
B. MPA, ram’s , 9 % of sodium chloride
C. MPA, rabbit’s red cells, 9 % of sodium chloride
D. MPA, horse’s red cells , 9 % of sodium chloride
E. MPA, glucose, 9 % chloride of sodium
An outbreak of sepsis caused by Staphylococcus aureus has occurred in the newborn nursery. You are
called upon to investigate. According to your knowledge of the normal flora, what is the MOST likely
source of the organism?
A. Colon
B. *Nose
C. Throat
D. Vagina
E. Smalll intestine
Each of the statements about the classification of streptococci is correct EXCEPT:
A. Pneumococci {Streptococcus pneumoniae) are alpha-hemolytic and can be serotyped on the
basis of their polysaccharide capsules
B. Enterococci are group D streptococci and can be classified by their ability to grow in 6.5%
sodium chloride
C. Although pneumococci and the viridans streptococci are alpha-hemolytic, they can be
differentiated by the bile solubility test and their susceptibility to optochin
D. *Viridans streptococci are identified by Lance-field grouping, which is based on the C
carbohydrate in the cell wall
E. No correct answer
Each of the following agents is a recognized cause of diarrhea EXCEPT:
A. Clostridium perfringens
B. Enterococcus faecalis
C. Escherichia coli
D. Rotavirus
E. *Vibrio cholerae
Residents of an assisted-living facility are immunized against Streptococcus pneumoniae. What is the
antigenic component of the vaccine?
A. A protein toxoid.
B. Killed whole bacteria.
C. Live bacteria of attenuated virulence
D. Purified toxin.
E. *Purified capsular polysaccharides.
An important virulence factor of coagulase-positive staphylococci is Protein A. How does Protein A aid
in virulence?
A. Binds the Fc region of IgG, decreases opsonization.
B. Hydrolyzes secretory IgA.
C. Binds Factor H, prevents activation of complement.
D. *Extracts iron from plasma proteins
E. Promotes tight binding of bacteria to extracellular matrix.
A patient with septicemia goes into septic shock. Blood cultures later show the pathogen to be Neisseria
meningitidis. Which component of the bacteria was most likely to be responsible for producing shock?
A. *Lipopolysaccharide [LPS].
B. Teichoic acid.
C. A superantigen toxin.
D. Capsular polysaccharide.
E. Plasma membrane lipids.
Which statement below most accurately describes the role of M protein in virulence of Group A
Streptococci [Streptococcus pyogenes]?
A. Shows no antigenic variation, so is not a target for antibodies.
B. Is a ‘superantigen toxin’ which stimulates TH cells.
C. *Stimulates synthesis of antibodies that cross-reacts with heart tissue.
D. Binds Fc regions of Immunoglobulin G molecules.
E. Inhibit phagocytosis
9. A child develops ‘strep throat’ (pharyngitis caused by Streptococcus pyogenes). The pediatrician
explains to the child’s mother that the pharyngitis normally resolves spontaneously but nevertheless it is
important the patient take a full course of Penicillin G. Why is this antibiotic treatment recommended in
this situation?
A. Shortens the course of the infection.
B. Prevents spread of the infection to adjacent sites.
C. *Prevents sequellae such as acute rheumatic fever.
D. Stimulates development of protective immunity.
E. Prevents spread of the infection to others.
10. A patient has endocarditis produced by an aд-hemolytic Streptococcus. This usually reflects spread of
normal flora to the bloodstream. From which site is this isolate most likely to have spread?
A. Anterior nares.
B. Facial skin.
C. Lower respiratory tract.
D. Distal urethra.
E. *Oropharynx.
11. From which site is a-hemolytic Streptococcus isolate most likely to have spread in blood?
A. Anterior nares.
B. *Oropharynx.
C. Lower respiratory tract.
D. Distal urethra.
E. Facial skin.
12. A nine years-old child develops high fever and stiff neck. A spinal tap is performed. A Gram-stained
smear of cerebrospinal fluid reveals many neutrophils and Gram-negative cocci that resemble paired
kidney beans within leucocytes. Which organism below is most likely to have caused this infection?
A. Escherichia coli
B. Haemophilus influenzae
C. Listeria monocytogenes
D. *Neisseria meningitidis
E. Streptococcus agalactiae
13. A patient presented with upper back pain. MRI imaging demonstrated inflammation of the T8-T9
vertebral bodies consistent with osteomyelitis. A bone marrow biopsy, when cultured, produced
colonies of Gram-positive cocci.Colonies on Sheep blood agar were 3-4 mm in diameter, off-white and
beta-hemolytic. Colonies on Brain-heart infusion (BHI) agar were 2-3 mm in diameter and goldenyellow. Catalase and coagulase tests were positive. What was the most likely pathogen?
A. *Staphylococcus aureus
B. Staphylococcus epidermidis
C. Streptococcus pyogenes
D. Streptococcus pneumoniae
E. Streptococcus mitis
14. A 20-year-old women presents at a local clinic with fever and abdominal tenderness. She reports having
had unprotected sexual intercourse a few weeks earlier. Gram-negative diplococci are seen in a Gram
stain of vaginal secretions; many of the bacteria are inside polymorphonuclear leukocytes. Which
virulence factor is most important in aiding this bacterium to initiate infection?
A. Ability to invade cells.
B. *Adhesive pili.
C. Anti-phagocytic capsule.
D. Endotoxin.
E. Flagella
15. Gram stain of CSF sediment from a patient with meningitis contains Gram-negative cocci, many in
pairs. Which organism below is most likely?
A. Streptococcus pneumoniae
B. Haemophilus influenzae
C. *Neisseria meningitidis
D. Pseudomonas aeruginosa
E. Escherichia coli
16. After Gram stain of spinal fluid sample from a patient with meningitis Medical personal during
microscopy examination detected Gram-negative cocci, many in pairs. Which organism below is most
likely?
A. *Neisseria meningitidis
B. Haemophilus influenzae
C. Streptococcus pneumoniae
D. Pseudomonas aeruginosa
E. Escherichia coli
17. Which test below would best distinguish S. aureus from one of the less-virulent staphylococci?
A. Production of catalase.
B. Colony color when grown on BHI agar.
C. Ability to grow on MacConkey agar.
D. *Production of coagulase.
E. Type of hemolysis on sheep blood agar.
18. How we can distinguish S. aureus from staphylococci epidermidis?
A. Production of catalase.
B. Colony color when grown on BHI agar.
C. Ability to grow on MacConkey agar.
D. Type of hemolysis on sheep blood agar.
E. *Production of coagulase.
19. The laboratory informs you that an isolate of Staphylococcus aureus is ‘methicillin-resistant’. Which
phrase below best describes such isolates?
A. Although resistant to methicillin, nearly all are sensitive to cephalosporins.
B. *They are resistant to both ‘anti-staph’ penicillins and cephalosporins.
C. They are seldom resistant to antibiotics other than ?-lactams.
D. They produce a ?-lactamase active on both cephalosporins and penicillins.
E. The ‘methicillin-resistance’ gene also confers resistance to vancomycin.
20. A young man has a large pus-filled abscess on his upper arm but does not go to a doctor. Several days
later he is brought to the Emergency Room with fever, hypotension, and multiple organ failure. Which
of the following is most likely to be responsible?
A. Streptococcus pyogenes Erythrogenic toxin.
B. Clostridium perfringens ?-toxin.
C. *Staphylococcus aureus Toxic Shock Syndrome Toxin-1.
D. Shigella dysenteriae Shiga Toxin.
E. Escherichia coli Heat-labile Toxin (ST).
21. Members of a family suffer acute attacks of nausea and vomiting a few hours after returning from a
daylong picnic, at which they ate hamburgers, potato salad, and custard pie. By morning all are feeling
better. Which bacterial toxin is most likely to have caused their symptoms?
A. Clostridium difficile Cytotoxin.
B. Escherichia coli Labile Toxin
C. Escherichia coli Stable Toxin.
D. *Staphylococcus aureus Enterotoxin.
E. Helicobacteri pylori Cytotoxin.
22. Five young men suffer acute attacks of nausea and vomiting a few hours after returning from a student’s
party, at which they ate hamburgers, potato salad, and custard pie. By morning all are feeling better.
Which bacterial toxin is most likely to have caused their symptoms?
A. *Staphylococcus aureus Enterotoxin.
B. Escherichia coli Labile Toxin
C. Escherichia coli Stable Toxin.
D. Clostridium difficile Cytotoxin.
E. Helicobacteri pylori Cytotoxin.
23. E. coli and Neisseria meningitidis isolated from blood cultures often have transport systems (for
acquiring metal ions from the environment) lacking in their less-virulent relatives. Which metal is
acquired by the majority of these systems?
A. Copper
B. Sodium
C. Potassium
D. Magnesium
E. *Iron
24. A 25-year-old woman presents with a swollen, warm, painful knee. Aspirated joint fluid is cloudy and
when cultured on chocolate agar gives rise to oxidase-positive colonies of Gram-negative diplococci.
Which bacterium is most likely to be the cause of this infection?
A. Haemophilus influenzae
B. Staphylococcus aureus
C. Streptococcus pneumoniae
D. *Neisseria gonorrhoeae
E. Nocardia asteroides
25. In cervical specimens of 21-year-old woman presents gram-negative diplococci within leucocytes.
Which bacterium is most likely to be the cause of this infection?
A. Haemophilus influenzae
B. *Neisseria gonorrhoeae
C. Streptococcus pneumoniae
D. Staphylococcus aureus
E. Nocardia asteroides
26. A workman has a large pus-filled lesion on the left forearm, tender, red, and swollen. It is incised. A
smear of the pus is Gram-stained. Many neutrophils are seen, also many Gram-positive cocci, most in
large clusters. The organism is b-hemolytic on sheep blood agar. Colonies are pale-yellow, opaque, and
shiny, with neat round outlines. Of the bacteria listed below, which is most likely to have produced the
abscess?
A. Streptococcus bovis
B. Streptococcus pneumoniae
C. Streptococcus mitis
D. Enterococcus faecalis
E. *Staphylococcus aureus
27. A young man complaines on pain on urination and profuse purulent discharge from his urethra. Gram
stain of the discharge revealed large numbers Gram-negative cocci, mostly in pairs within neutrophils.
Which bacterium is most likely to have caused his infection?
A. Mycoplasma hominis
B. Chlamydia trachomatis
C. *Neisseria gonorrhoeae
D. Ureaplasma urealyticum
E. Treponema pallidum
28. A 17-year-old sexually-active male presents with a four-day history of pain on urination and profuse
purulent discharge from his urethral opening. Gram stain of the discharge revealed large numbers of
neutrophils. A small fraction of neutrophils contained Gram-negative cocci, mostly in pairs. Which
bacterium is most likely to have caused his infection?
A. Mycoplasma hominis
B. Chlamydia trachomatis
C. Treponema pallidum
D. Ureaplasma urealyticum
E. *Neisseria gonorrhoeae
29. An 18-year-old high school student has a large pus-filled lesion on the left forearm, tender, red, and
swollen. It is incised, drained, washed, and bandaged. A smear of the pus is Gram-stained. Many
neutrophils are seen, also many Gram-positive cocci, most in large clusters. The organism is bhemolytic on sheep blood agar. Colonies are pale-yellow, opaque, and shiny, with neat round outlines.
Of the bacteria listed below, which is most likely to have produced the abscess?
A. *Staphylococcus aureus
B. Streptococcus pneumoniae
C. Streptococcus mitis
D. Enterococcus faecalis
E. Streptococcus bovis
30. Heavily-encapsulated strains of Neisseria meningitidis are far more virulent than non-encapsulated
isolates. How does a capsule enhance virulence?
A. Binds to the Fc region of some subclasses of human IgG.
B. Prevents activation of complement by the classical pathway.
C. Enables bacteria to adhere tightly to mammalian cells.
D. Reduces access of antibiotics to the bacterial membrane.
E. *Inhibits phagocytosis by neutrophils
31. A post-surgical patient develops fever and there is redness and swelling around the surgical incision. A
day later pus begins to flow from the incision; Gram stain of pus shows large numbers of neutrophils
and many Gram-positive cocci, some in clusters. The organism is beta-hemolytic on blood agar, and is
coagulase- and catalase-positive. Which organism is most likely?
A. *Staphylococcus aureus
B. Staphylococcus epidermidis
C. Streptococcus pyogenes (Group A)
D. Streptococcus agalactiae (Group B)
E. Streptococcus pneumoniae
32. A beta-hemolytic streptococcus is isolated from an infected neonate. Such isolates are often members of
Lancefield Group B. The antigenic structure of which bacterial component defines Lancefield Groups?
A. Capsule polysaccharide.
B. *Cell-associated or C-carbohydrate.
C. Wall and membrane teichoic acids.
D. Beta-hemolysins.
E. Filamentous proteins of the cell envelope.
33. In the immune response to invasive infections by Streptococcus pneumoniae, antibodies are required for
effective defense. Antibodies to which antigen are most important?
A. Teichoic acid.
B. Peptidoglycan.
C. C-carbohydrate.
D. Type III secretion system.
E. *Polysaccharide capsule.
34. The main carrier site on the human body for strains of potentially pathogenic Staphylococcus aureus is
the
A. oral cavity
B. *throat (posterior nasopharynx)
C. nasal membranes
D. gastrointestinal tract
E. vagina
35. The carrier site in humans for pathogenic Neisseria meningitidis is the
A. Conjunctiva
B. *nasopharynx
C. urogenital tract
D. blood
E. meninges
36. Silver nitrate or an antibiotic is put into the eyes of newborn infants to prevent infection by
A. Doderlein's bacillus (Lactobacillus acidophilus)
B. Herpes simplex virus
C. *Neisseria gonorrhoeae
D. Chlamydia trachcomatis
E. two of the above
37. A characteristic of Streptococcus mutans that allows it to initiate dental plaque and dental caries is:
A. the ability to attach specifically to the pellicle of the tooth
B. the ability to utilize sucrose as a source of carbon and energy
C. the ability to produce a dextran capsule
D. * the ability to produce lactic acid
E. all are true
38. The fibrin coat that can be formed by coagulase-positive staphylococci and the hyaluronic acid capsule
of Streptococcus pyogenes are pathogenic strategies to
A. promote colonization of a host
B. cause direct damage to host cells during pathogenesis
C. hide bacterial antigens from the host immune tissues
D. *survive as intracellular parasites
E. alter or change their surface antigens within the course of an infection
39. Leukocidins are
A. enzymes contained in the lysosomes of phagocytes to kill ingested bacteria
B. proteins produced by bacteria that kill closely-related bacteria
C. proteases produced by bacteria which destroy host immunoglobulins
D. enterotoxins produced by Staphylococcus aureus involved in food-borne disease
E. * substances produced by pyogenic bacteria that kill phagocytes
40. The streptococcal invasin which behaves as a "spreading factor" by breaking down the framework of
connective tissues is called
A. Collagenase
B. Streptokinase
C. Streptolysin
D. erythrogenic toxin (pyogenic exotoxin)
E. * hyaluronidase
41. A primary determinant of virulence in Streptococcus pyogenes, which is involved in adherence,
resistance to phagocytosis and antigenic variation, is
A. Streptokinase
B. lipopolysaccharide (endotoxin)
C. *M-protein
D. Protein A
E. coagulase
42. The similarity between the toxic shock syndrome toxin (TSST), the staph enterotoxins, and the
erythrogenic toxin (pyogenic exotoxin) is
A. they are all produced by Staphylococcus aureus
B. *they stimulate the immune system in a similar manner as superantigens
C. the pathology of the diseases that they cause is identical
D. they are all neurotoxins
E. they are the same (identical) toxin produced by three different organisms
43. The main carrier site on the human body for strains of potentially pathogenic Neisseria meningitidis is
the
A. nasal membranes
B. * throat (posterior nasopharynx)
C. oral cavity
D. gastrointestinal tract
E. vagina
44. Characteristics of Streptococcus mutans which allow it to initiate dental caries include
A. the ability to attach specifically to the pellicle of the tooth
B. *the ability to produce lactic acid from sucrose, glucose and fructose
C. the ability to form and grow in a biofilm on the enamel of the tooth
D. all are true
E. all are false
45. A determinant of virulence of Streptococcus pneumoniae which allows the bacteria to resist engulfment
by phagocytes is
A. fimbriae
B. *a polysaccharide capsule
C. production of TSST exotoxin
D. coagulase
E. neuraminidase
46. The fimbriae of pathogenic Neisseria gonorrhoeae are apparently essential to the bacterium when it
produces the disease gonorrhea because
A. *they are responsible for initial attachment of the bacteria to the urethral or cervical epithelium
B. they cause the production of pus which is characteristic of gonorrhoea
C. they make the bacteria resistant to phagocytic killing and digestion by white blood cells
D. they convert urinary tract components (urine) to substances which provoke symptoms of disease
E. they allow the bacteria to swim "upstream" against the flow of urine and thereby remain
established in the urinary tract
47. Which bacterial invasin is mismatched with its activity in the host?
A. staphylokinase: degrades fibrin
B. coagulase: clots fibrin
C. *hyaluronidase: degrades the ground substance of connective tissue
D. streptolysin: lyses neutrophil membranes
E. all are false
48. The fibrin coat that can be formed by coagulase-positive staphylococci and the hyaluronic acid capsule
of Streptococcus pyogenes are pathogenic strategies to
A. promote colonization of a host
B. cause direct damage to host cells during pathogenesis
C. hide bacterial antigens from the host immune tissues
D. *survive as intracellular parasites
E. alter or change their surface antigens during the course of an infection
49. What bacterial structure or substance is primarily associated with antigenic variation in the Group A
streptococci?
A. outer membrane protein (omp)
B. streptokinase
C. hyaluronic acid capsule
D. *Polysaccharide
E. M-protein
50. Which of the following bacterial toxins behaves as a superantigen through its stimulation of a very large
fraction of the host T-cell population?
A. Streptococcal streptolysin
B. Salmonella LPS (endotoxin)
C. Pseudomonas Exotoxin A
D. *Staphylococcal toxic shock syndrome toxin
E. E. coli O157 H:7 shiga toxin
51. Scalded skin syndrome is due to which toxin of Staphylococcus aureus?
A. *Epidermolytic toxin.
B. Enterotoxin.
C. Leucocidin.
D. Haemolysin
E. Necrotoxin
52. Isolation of pneumococci from clinical specimens may be attempted by intraperitoneal inoculation
A. rabbits.
B. rats.
C. *mice.
D. sheep.
E. Mice
53. Which of the following organisms may lead to pseudomembrane formation in the throat?
A. Corynebaclerium diphtheriae
B. Treponema Vinsentii
C. Streptococcus pyogenes.
D. Candida albicans.
E. *All are true
54. Most strains of Staphylococcus aureus show:
A. *a golden-yellow pigment.
B. ?-haemolysis on sheep blood agar.
C. phosphatase production.
D. novobicin resistance
E. all are true.
55. A positive Schick test implies that the person is:
A. immune and non-hypersensitive.
B. *susceptible and non-hypersensitive.
C. immune and hypersensitive.
D. non-immune and hypersensitive.
E. healthy
56. Which of the following agents is the commonest cause of infective endocarditis?
A. Staphylococcus epidermidis.
B. Candida spp.
C. *Viridans group of streptococci.
D. Coliforms.
E. Rickettsia
57. Which of the following bacteria ferment mannitol anaerobically?
A. *Staphylococcus aureus.
B. S. epidermidis.
C. S. saprophyticus.
D. S. canis
E. All are true.
58. 70. Which of the following are pyogenic cocci:
A. Streptococcus
B. Staphylococcus
C. Pneumococcus
D. Neisseria
E. *all are true
59. The coagulase test is used to differentiate Staphylococcus aureus from
A. other staphylococci
B. *streptococci
C. micrococci
D. enterococci
E. pneumococci
60. The symptoms in scarlet fever are due to
A. streptolysin
B. coagulase
C. *pyrogenic toxin
D. alpha toxin
E. leucocidin
61. Penicillin-resistant Staphylococcus can be treated with ______ without sensitivity testing.
A. ampicillin
B. erythromycin
C. methicillin
D. amoxycillin
E. *no antibiotic
62. The most severe streptococcal diseases are caused by
A. *group A streptococci
B. group B streptococci
C. group C streptococci
D. pneumococci
E. enterococci
63. Rheumatic fever damages the _______, and glomerulonephritis damages the______
A. skin, heart
B. joints, bone marrow
C. *heart valves, kidney
D. brain, kidney
E. heart, bone marrow
64. ______ hemolysis is the partial lysis of red blood cells due to bacterial hemolysins.
A. * Alpha
B. Beta
C. Gamma
D. Delta
E. Epsilon
65. An effective vaccine exists to prevent infections from
A. Staphylococcus aureus
B. Streptococcus pyogenes
C. Neisseria gonorrhoeae
D. *Streptococcus pneumoniae
E. Streptococcus epidermidis
66. Viridans streptococci commonly cause
A. pneumonia
B. meningitis
C. *subacute endocarditis
D. otitis media
E. arthritis
67. Which genus of bacteria has pathogens that can cause blindness and deafness?
A. Branhamella
B. Staphylococcus
C. Streptococcus
D. *Neisseria
E. Shigella
68. An important test for identifying Neisseria is
A. *production of oxidase
B. production of catalase
C. sugar fermentation
D. beta-hemolysis
E. alfa- hemolysis
69. A complication of genital gonorrhea in both men and women is
A. *infertility
B. pelvic inflammatory disease
C. arthritis
D. blindness
E. E. urethritis
70. The skin blotches in meningitis are due to
A. blood clots
B. *endotoxins in the blood
C. erysipelas
D. exotoxin in skin
E. E. skin invasion by N. meningitidis
71. Which infectious agent of those covered in the chapter would most likely be acquired from a
contaminated doorknob?
A. Staphylococcus epidermidis
B. Streptococcus pyogenes
C. Neisseria meningitidis
D. Streptococcus pneumoniae
E. *Staphylococcus aureus
72. A child develops pneumonia. The bacterium Streptococcus pneumoniae is cultured from the patient’s
sputum. Cells of the cultured bacteria have thick polysaccharide capsules. How did the presence of
capsules promote development of serious disease?
A. Prevented binding of antibodies to the bacteria.
B. Prevented initiation of a humoral immune response.
C. Prevented activation of helper T cells.
D. *Prevented phagocytosis by neutrophils.
E. Prevented mast-cell degranulation.
73. An elderly man develops pneumonia and septicemia. Gram stain of sputum contains many neutrophils
and Gram-positive cocci, in pairs. Blood and sputum cultures grow out a Gram-positive coccus, ?hemolytic on sheep blood agar, and catalase-negative. Which organism below is most likely?
A. Staphylococcus epidermidis.
B. Staphylococcus aureus.
C. *Streptococcus pneumoniae.
D. Streptococcus pyogenes.
E. Streptococcus agalactiae.
74. Staphylococcus aureus is easily transmitted within the hospital environment. Which feature of this
bacterium is most largely responsible for its ease of spread?
A. *Resistance to heat, cold, and drying.
B. Ability to colonize the digestive tract.
C. Presence of an outer membrane impermeable to most disinfectants.
D. Production of extracellular polysaccharide which allows it to adhere tightly to surfaces.
E. Ability to form spores which are resistant to disinfectants and easily dispersed.
75. A 23-year-old medical student had headache and fever one evening. By the next morning she had
become very ill, with high fever, severe headache, and stiff neck. She was admitted to the hospital. Later
that day she developed rash, at first petechial and then pupuric. Gram stain of CSF showed many white
cells and Gram-negative cocci, many in pairs. Which organism is most likely to be the cause of her
infection?
A. Escherichia coli.
B. Haemophilus influenzae.
C. *Neisseria meningitidis.
D. Streptococcus agalactiae.
E. Streptococcus pneumoniae.
76. A patient has cellulitis of the left arm, persistent fever, and a heart murmur. He is a habitual user of
illegal drugs, which he self-administers intravenously. An echocardiogram shows a bacterial vegetation
on the aortic valve. Three blood cultures all grow an ?-hemolytic Gram-positive coccus,
catalasenegative. Which organism is most likely to have caused his infection?
A. Staphylococcus aureus.
B. *A Viridans-group Streptococcus.
C. Streptococcus pyogenes [Group A].
D. Streptococcus agalactiae [Group B].
E. Streptococcus bovis [Group D].
77. Untreated pharyngitis produced by Group A streptococci can result in later development of Acute
rheumatic fever, created by cross-reaction of anti-streptococcal antibodies with heart tissue. Which
streptococcal antigen stimulates formation of these cross-reactive antibodies?
A. A.Group A carbohydrate.
B. Flagella.
C. *M protein
D. Peptidoglycan.
E. Teichoic acid.
78. A neonate develops septicemia. Blood cultures produce a ?-hemolytic Gram-positive coccus. It is
catalase negative. Which test would best confirm the identity of the pathogen as a Group B
Streptococcus?
A. *Synergy of hemolysin with the hemolysin of Staphylococcus aureus [CAMP test].
B. Bile-esculin test.
C. Bacitracin sensitivity.
D. Optochin sensitivity.
E. Novobiocin sensitivity.
79. A individual may have repeated infections with Neisseria gonorrhoeae, despite the fact that each
infection gives rise to an immune response. By which mechanism does the gonococcus evade protective
immunity?
A. Thick capsule prevents binding of antibodies to the cell surface.
B. Pili adhere to epithelial cells despite binding of antibodies.
C. Capsular polysaccharide is identical to polysaccharides of mammalian cells.
D. Outer membrane lacks any antigenic components.
E. *The surface antigens present change continually, as a result of pre-programmed changes in
DNA.
80. An elderly resident of a nursing home develops pneumococcal pneumonia. This illness might have been
prevented had the patient been immunized against this organism. Which antigens of S. pneumoniae are
included in the adult vaccine?
A. M-proteins.
B. Intact heat-killed bacteria.
C. Toxoids produced from superantigen toxins.
D. *Capsular polysaccharides.
E. Cell-associated (C) carbohydrates.
81. Before the advent of immunization, outbreaks of meningococcal disease were frequent in military
camps. A factor in development of such outbreaks is the ability of Neisseria meningitidis to establish an
asymptomatic ‘carrier state’. What is the predominant site of carriage of Neisseria?
A. Urethral epithelium.
B. Gall bladder.
C. Large intestine.
D. *Nasopharynx.
E. Meninges and choroid plexus
82. A patient develops pneumonia caused by Streptococcus pneumoniae. The predominant virulence factor
of this organism is a thick capsule . Which phrase best describes the role of this capsule in virulence?
A. Aids in acquisition of iron.
B. Toxic to lung epithelial cells
C. Identical to human polysaccharide, so is non-immunogenic.
D. *Reduces phagocytosis by neutrophils.
E. Inhibits activation of Complement.
83. Which of the following statements best describes Streptococcus pneumoniae?
A. *bile soluble, optochin sensitive, capsulated
B. bile soluble, catalase negative, noncapsulated
C. bile soluble, gramnegative, optochin resistant
D. bile soluble, catalase positive, optochin sensitive
E. bile soluble, catalase negative, motily
84. Which of the following is a pathogen of the oropharynx?
A. Streptococcus pneumoniae
B. *Streptococcus pyogenes
C. Streptococcus bovis
D. Streptococcus viridans
E. Enterococcus faecalis
85. What do endotoxins and exotoxins have in common?
A. secreted into the medium
B. *cause damage to the host
C. heat stable
D. heat resistent
E. contain polysaccharide
86. Which virulence factor results in the symptoms of Staphylococcal food poisoning?
A. exfoliative exotoxin
B. hyaluronidase
C. endotoxin
D. *enterotoxin
E. neurotoxin
87. Which of the following best describes the pathogenesis of acute rheumatic fever?
A. *characterized by inflammation of the heart and/or the joints
B. due to an immunologic cross reaction between heart muscle and Staphylococcus aureus
C. involves B-hemolytic Streptococci growing in the heart
D. is a complication of Group A Streptococcal skin disease as well as pharyngitis
E. tonsilitis is first stage of development of rheumatic fever
88. Which of the following statements about gonorrhea is true?
A. Men are frequently asymptomatic carriers.
B. Bacteremia is common.
C. Serologic diagnosis is more reliable than culture.
D. Penicillins are no longer recommended for treatment.
E. *Gonococci are within leucocytes in a sample
89. Which test result would rule out an Enterococcus isolate?
A. growth in 6.5% NaCl
B. *oxidase positive
C. catalase negative
D. PYR positive
E. motility
90. What is the most common cause of urinary tract infections?
A. Staphylococcus saprophyticus
B. Escherichia coli
C. *Enterococcus fecalis
D. Streptococcus bovis
E. Staphylococcus epidermidis
91. Which of the following is NOT true of Neisseria gonorrhea?
A. Is a mucosal pathogen
B. *Requires a vaginal pH of 5 or more to grow
C. Can disseminate in the immunosuppressed
D. Complications include ectopic pregnancy, PID and sterility
E. Gram-negative diplococci
92. Which of the following is NOT true of Neisseria meningitidis?
A. Crosses the blood brain barrier
B. *Has 3 serotypes - A, B, Y
C. Colonizes nasopharynx
D. Predisposed groups include diabetics
E. Has peptidoglycan
93. An outbreak of sepsis caused by Staphylococcus aureus has occurred in the newborn nursery. You are
called upon to investigate. According to your knowledge of the normal flora, what is the MOST likely
source of the organism?
A. Colon
B. *Nose
C. Throat
D. Vagina
E. All are true
94. Each of the statements about the classification of streptococci is correct EXCEPT:
A. Pneumococci {Streptococcus pneumoniae) are alpha-hemolytic and can be serotyped on the
basis of their polysaccharide capsules
B. Enterococci are group D streptococci and can be classified by their ability to grow in 6.5%
sodium chloride
C. Although pneumococci and the viridans streptococci are alpha-hemolytic, they can be
differentiated by the bile solubility test and their susceptibility to optochin
D. *Viridans streptococci are identified by Lance-field grouping, which is based on the C
carbohydrate in the cell wall
E. All are true
95. Each of the following agents is a recognized cause of diarrhea EXCEPT:
A. Clostridium perfringens
B. *Enterococcus faecalis
C. Escherichia coli
D. Vibrio cholerae
E. All are true
96. Your patient is a 30-year-old woman with nonbloody diarrhea for the past 14 hours. Which one of the
following organisms is LEAST likely to cause this illness?
A. Clostridium difficile
B. *Streptococcus pyogenes
C. Shigella dysenteriae
D. Salmonella enteritidis
E. All are true
97. Your patient has subacute bacterial endocarditis caused by a member of the viridans group of
streptococci. Which one of the following sites is MOST likely to be the source of the organism?
A. Skin
B. Colon
C. *Oropharynx
D. Urethra '
E. All are true
98. A culture of skin lesions from a patient with pyoderma (impetigo) shows numerous colonies surrounded
by a zone of beta hemolysis on a blood agar plate. A Gram-stained smear shows gram-positive cocci. If
you found the catalase test to be negative, which one of the following organisms would you MOST
probably have isolated?
A. *Streptococcus pyogenes
B. Staphylococcus aureus
C. Staphylococcus epidermidis
D. Streptococcus pneumoniae
E. All are true
99. The coagulase test, in which the bacteria cause plasma to clot, is used to distinguish
A. Streptococcus pyogenes from Enterococcus faecalis
B. Streptococcus pyogenes from Staphylococcus aureus
C. *Staphylococcus aureus from Staphylococcus epidermidis
100.
D. Staphylococcus epidermidis from Neisseria meningitidis
F. All are true
101.
Which one of the following is considered a virulence factor for Staphylococcus aureus?
A. A heat-labile toxin that inhibits glycine release at the internuncial neuron
B. An oxygen-labile hemolysin
C. Resistance to novobiocin
D. *Protein A that binds to the Fc portion of IgG
E. All are true
102.
Each of the following statements concerning Staphylococcus aureus is correct EXCEPT:
A. Gram-positive cocci in grapelike clusters are seen on Gram-stained smear
B. The coagulase test is positive
C. Treatment should include a (3-lactamase-resistant penicillin
D. *Endotoxin is an important pathogenetic factor
E. All are true
103.
Two hours after a delicious Thanksgiving dinner of barley soup, roast turkey, stuffing, sweet
potato, green beans, cranberry sauce, and pump kin pie topped with whipped cream, the Smith family of
four experience vomiting and diarrhea. Which one of the following organisms is MOST likely to cause
these symptoms?
A. Shigella flexneri
B. Campylobacter jejuni
C. *Staphylococcus aureus
D. Salmonella enteritidis
E. All are true
104.
The MOST important contribution of the capsule of Streptococcus pneumoniae to virulence is
A. To prevent dehydration of the organisms on mucosal surfaces
B. *To retard phagocytosis by polymorphonuclear leukocytes
C. To inhibit polymorphonuclear leukocyte chemo taxis
D. To accelerate tissue invasion by its collage-naselike activity
E. All are true
105.
The MOST important way the host circumvents the function of the pneumococcal
polysaccharide capsule is via
A. T lymphocytes sensitized to polysaccharide antigens
B. Polysaccharide-degrading enzymes
C. *Anticapsular antibody
D. Activated macrophages
E. All are true
106.
Each of the following statements concerning staphylococci is correct EXCEPT:
A. S. aureus is differentiated from S. epidermidis by the production of coagulase
B. S. aureus infections are often associated with abscess formation
C. The majority of clinical isolates of S. aureus elaborate penicillinase; therefore, presumptive
antibiotic therapy for S. aureus infections should not consist of penicillin G
D. *Scalded skin syndrome caused by S. aureus is due to enzymatic degradation of epidermal
desmosomes by catalase
E. All are true
107.
Regarding the effect of benzylpenicillin (penicillin G) on bacteria, which one of the following
organisms is LEAST likely to be resistant?
A. Staphylococcus aureus
B. Enterococcus faecalis
C. *Streptococcus pyogenes
D. Neisseria gonorrhoeae
E. All are true
108.
Which one of the following is NOT an important characteristic of either Neisseria gonorrhoeae
or Neisseria meningitidis?
A. Polysaccharide capsule
B. IgA protease
C. *M protein
D. Pili
E. All are true
109.
Which one of the following is NOT an important characteristic of Streptococcus pyogenes?
A. *Protein A
B. M protein
C. Beta-hemolysin
D. Polysaccharide group-specific substance
E. All are true
110.
Three organisms, Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus
influenzae cause the vast majority of cases of bacterial meningitis. What is the MOST important
pathogenic component they share?
A. Protein A
B. *Capsule
C. Endotoxin
D. beta-Lactamase
E. All are true
111.
Tissue-degrading enzymes play an important role in the pathogenesis of several bacteria. Which
one of the following is NOT involved in tissue or cell damage?
A. Lecithinase of Clostridium perfringens
B. Hyaluronidase of Streptococcus pyogenes
C. *M protein of Streptococcus pneumoniae
D. Leukocidinof Staphylococcus aureus
E. All are true
112.
Of the organisms listed below, which one is the MOST frequent bacterial cause of pharyngitis?
A. Staphylococcus aureus
B. Streptococcus pneumoniae
C. *Streptococcus pyogenes
D. Neisseria meningitidis
E. All are true
113.
Each of the following statements concerning gonorrhea is correct EXCEPT:
A. Infection in men is more frequently symptomatic tY\an in women
B. A presumptive diagnosis can be made by finding gram-negative kidney-bean-shaped diplococci
within neutrophils in a urethral discharge
C. *The definitive diagnosis can be made by detecting at least a 4-fold rise in antibody to Neisseria
gonorrhoeae
D. Gonococcal conjunctivitis of the newborn rarely occurs in the United States, because silver
nitrate or erythromycin is commonly used as prophylaxis
E. All are true
114.
Each of the following statements concerning neisseriae is correct EXCEPT:
A. They are gram-negative diplococci
B. They produce IgA protease as a virulence factor
C. They are oxidase-positive
D. *They grow best under anaerobic conditions
E. All are true
115.
Each of the following statements concerning Neisseria meningitidis is correct EXCEPT:
A. It is an oxidase-positive, gram-negative diplo-coccus
B. It contains endotoxin in its cell wall
C. *It produces an exotoxin that stimulates adenylate cyclase
D. It has a polysaccharide capsule that is antiphagocytic
E. All are true
116.
Which organism below, if present in only one of three blood cultures from a single patient, is
most likely to represent contamination caused by poor antiseptic technique, rather than genuine
infection?
A. *Staphylococcus epidermidis.
B. Streptococcus pneumoniae.
C. Escherichia coli.
D. Pseudomonas aeruginosa.
E. Haemophilus influenzae.
117.
An 81-year-old man with chronic emphysemea and hypertension develops fever, chills, and
respiratory distress. X-rays show lobar pneumonia. Sputum smear contains numerous Gram-positive
cocci, many of which are in pairs. Sputum culture on Sheep blood agar produces many colonies of an
alpha-hemolytic Gram-positive coccus. It is catalase-negative, Bile-esculin negative, and optochinsensitive. Which of the organisms below is most likely?
A. Streptococcus pyogenes (Group A)
B. Streptococcus agalactiae (Group B)
C. Streptococcus mitis
D. Streptococcus bovis (Group D)
E. *Streptococcus pneumoniae
118.
A post-surgical patient develops redness around the incision and a day later pus begins to ooze
from the wound. Culture of a swab of pus produces beta-hemolytic colonies on Sheep blood agar. Gram
stain shows that the bacteria are Gram-positive cocci. Catalase and coagulase tests are positive. Which
of the following organisms is most likely?
A. Streptococcus pyogenes
B. Streptococcus agalactiae
C. Streptococcus mitis
D. *Staphylococcus aureus
E. Staphylococcus epidermidis
119.
A 75-year-old man reports malaise, headache, and fever. On examination his neck is stiff. Gram
stain of CSF reveals neutrophils and numerous Gram-negative cocci, many in pairs.Which organism
below is most likely?
A. Pseudomonas aeruginosa
B. Klebsiella pneumoniae
C. Haemophilus influenzae
D. Neisseria gonorrhoeae
E. *Neisseria meningitidis
120.
A 19-year-old man comes to your clinic because of thick purulent discharge from the urethral
opening of his penis. On Gram-stain of the discharge huge numbers of neutrophils are seen, a few of
which contain intracellular Gram-negative cocci. Many of the cocci are in pairs. What is the most likely
organism?
A. Neisseria meningitidis.
B. *Neisseria gonorrhoeae.
C. Haemophilus ducreyi.
D. Mycoplasma hominis.
E. Treponema pallidum.
121.
What is the most common outcome of infection with Helicobacter pylori?
A. Severe diarrhea
B. No clinical manifestations
C. Bacteremia
D. Hepatitis
E. *Peptic ulcers or gastric cancer
122.
A 35-year old patient got fever, nausea, vomiting and bloody diarrhea, all of the following
bacteria should be considered in the diffrential diagnosis, except one:
A. Salmonella
B. ETEC
C. Shigella
D. Yersinia
E. *Campylobacter
123.
A 38 years old patient has chronic gastritis. Which of the following organisms is most likely?
A. Campylobacter fetus.
B. Escherichia coli.
C. A non-cholera Vibrio.
D. Campylobacter jejuni.
E. *Helicobacter pylori.
124.
A 40-years-old patient has a peptic ulcer. Which organism is most likely to have created this
lesion?
A. Campylobacter jejuni.
B. Enterococcus faecalis.
C. Escherichia coli.
D. Salmonella enteritidis
E. *Helicobacter pylori
125.
A 5-years-old girl develops bloody diarrhea, produced by Shigella infection. From which source
was this infection most likely to have been contracted?
A. Rare hamburger.
B. Dog or cat.
C. Spores present in soil.
D. Cow, horse, or sheep.
E. *Another child.
126.
A 6-year-old boy was brought to the emergency room with a history of bloody diarrhea over the
preceding two days. A fecal smear contained numerous red cells and neutrophils. Stool culture on Endo
agar produced lactose-negative colonies amid colonies of ‘normal intestinal flora’. Which of the
organisms below is most likely to be the cause of his illness?
A. Enteropathogenic E. coli
B. Balantidium coli.
C. Entamoeba histolytica
D. Giardia lamblia.
E. *Shigella.
127.
A few healthy adult travelers visiting Peru are cautioned against eating uncooked vegetables and
unpeeled fruits, and against drinking unbottled water. However, they are already resistant to cholera
because of:
A. the gamma globulin shots they received before their trip.
B. their ability to avoid contaminated food due to its acidic smell.
C. they were vaccinated
D. their consumption of large prophylactic amounts of bicarbonates.
E. *a gastric barrier, due to stomach acids.
128.
A four-year-old boy was brought to the emergency room with a history of bloody diarrhea over
the preceding two days. A fecal smear contained numerous red cells and neutrophils. Stool culture on
Endo agar produced lactose-negative colonies amid colonies of ‘normal intestinal flora’. Which of the
organisms below is most likely to be the cause of his illness?
A. Enteropathogenic E. coli
B. Balantidium coli.
C. Entamoeba histolytica
D. Giardia lamblia.
E. *Shigella.
129.
A four-year-old boy was brought to the emergency room with a history of bloody diarrhea over
the preceding two days. A fecal smear contained numerous red cells and neutrophils. Stool culture on
Endo agar produced lactose-negative colonies amid colonies of ‘normal intestinal flora’. Which of the
organisms below is most likely to be the cause of his illness?
A. Enteropathogenic E. coli
B. Balantidium coli.
C. Entamoeba histolytica
D. Giardia lamblia.
E. *Shigella.
130.
A laboratory got a sample from a patient with cholera. Which of the following tests would not
differentiate Vibrio cholera non O1 from Vibrio parahaemolyticus?
A. oxidase activity.
B. Growth on special blood agar
C. Production of enterotoxin
D. Growth on salt-free and salt-containing agar.
E. *Growth on TCBS agar
131.
A laboratory got a sample from a patient with cholera. Which of the following is not true about
the bacterium classified as Vibrio cholerae (V. cholerae О1):
A. causes disease only through the production of an enterotoxin
B. reacts with group 1 antiserum against the lipopolysaccharide (О) antigens
C. arabinose is not fermented
D. invades the small intestine
E. *is often associated with marine environments
132.
A laboratory got a sample from a patient with diarrhoea. Which of the following media is an
enrichment medium for the isolation of Shigella?
A. Tetrathionate broth.
B. Alkaline peptone water.
C. Taurocholate peptone transport and enrichment medium.
D. Endo medium
E. *Selenite broth.
133.
A laboratory got a sample from a patient with diarrhoea. Cholera toxin resembles which of the
following toxins?
A. Stable toxin of E. coli.
B. Diphtheria toxin.
C. Tetanus toxin.
D. Staphylococcus enterotoxin
E. *Labile toxin of Escherichia coli.
134.
A laboratory got a sample from a patient with diarrhoea. To test a stool specimen for
Campylobacter, all of the following measures would be used except:
A. Plating on agar containing glucose or sucrose
B. Plating on Campy blood agar containing 5 antibiotics
C. Incubating the plates in an atmosphere of 5% O2, 10% CO2
D. Incubating the plates at 42° C
E. *Passing the samples through 0.45 micron filters
135.
A laboratory got a sample from a patient with diarrhoea. Shigella is transmitted by
A. ticks
B. direct contact
C. air dropled
D. louse
E. *infected food and water
136.
A laboratory got a sample from a patient with diarrhea. The severe diarrhea of cholera is
produced by a protein exotoxin that acts on enterocytes. Which statement below best describes the effect
of Cholera toxin?
A. Alters the actin cytoskeleton.
B. Inactivates ribosomes.
C. Stimulates guanyl cyclase.
D. Proteolytic cleavage of a specific cellular protein.
E. *Stimulates adenyl cyclase.
137.
A laboratory got a specimen from a patient with cholera. The following occurs during the course
of disease due to Vibrio cholerae infection, except one:
A. Patients experience nausea, vomiting, abdominal cramping, and diarrhea.
B. Patients sometimes lose between 10 to 20 liters of fluid/day.
C. “Rice-water” stool presents
D. Patients show signs of disease at 8 to 72 hrs after ingestion of contaminated food or water.
E. *Patients sustain considerable damage to their intestines.
138.
A man, 38 y.o. has gastritis. The pathogenic mechanisms that make Helicobacter pylori the
causative agent of gastritis include the following except:
A. urease production
B. catalase production
C. microaerophilism
D. motility
E. *invasive abilities
139.
A microbiologist got a sample from a patient with cholera. Which of the following statements is
true about the toxin produced by Vibrio cholera?
A. The B subunit directly stimulates the host adenylate cyclase.
B. The toxin blocks the host adenylate cyclase.
C. The toxin is lypopolisaccharide
D. It has its own adenylate cyclase activity.
E. *The A1 subunit indirectly stimulates the host adenylate cyclase.
140.
A microbiologist got a specimen from a patient with cholera. To determine to which species of
vibrios infectious agent belongs, the microbiologist performs some tests on colonies cultured from stool
samples. These tests include the following EXCEPT:
A. growth on thiosulfate-citrate-bile-sucrose (TCBS) agar
B. fermentation of sucrose
C. phagotyping
D. growth at different NaCl concentrations
E. *serotyping based on H antigens
141.
A middle aged man recently returned from visiting his family in India develops severe diarrhea.
He in fact has cholera. His diarrhea is produced by a protein exotoxin secreted by Vibrio cholerae. How
does this toxin act?
A. ADP-ribosylates a chloride transporter.
B. Stimulates guanyl cyclase.
C. Inhibits guanyl cyclase.
D. Inhibits a G protein that inhibits adenyl cyclase.
E. *Stimulates a G protein that activates adenyl cyclase.
142.
A motive not to administer beta lactam antibiotics for a Gram-negative septicemia, unless there
is no other alternative, is
A. the lysis of bacterial cells increases the activity of bacterial LPS
B. Complement activation cannot occur in the presence of the antibiotic
C. the antibiotic suppresses the immune response necessary to eliminate the pathogen
D. the antibiotic eliminates the normal flora
E. *beta lactam antibiotics are ineffective against Gram-negative bacteria
143.
A patient got diarrhoea. The pathogenesis of which one of the following organisms is MOST
likely to involve invasion of the intestinal mucosa?
A. Enterotoxigenic Escherichia coli
B. Clostridium botulinum
C. Enteropathogenic Escherichia coli
D. Vibrio cholerae
E. *Shigella sonnei
144.
A patient got severe diarrhoea. If this patient had Shigellosis, the stool culture on MacConkey
agar will grow:
A. glucose fermenting colonies
B. pink colonies
C. black colonies
D. lactose fermenting colonies
E. *non-lactose fermenting colonies
145.
A patient has a peptic ulcer. Which organism is most likely to have created this lesion?
A. Campylobacter jejuni.
B. Enterococcus faecalis.
C. Salmonella enteritidis
D. Escherichia coli.
E. *Helicobacter pylori
146.
A patient has been diagnosed with a gastric ulcer. A test of the patient's serum shows reactivity
with Helicobacter pylori antigens. Which of the following is true?
A. The patient's gastrin-hydrochloric homeostasis has been maintained.
B. Damage to the patient's gastric mucosa has been primarily caused by the patient's own immune
response.
C. All are true
D. The Helicobacter pylori infection most likely has nothing to do with the patient's condition.
E. *The patient will be treated with amoxicillin to eradicate H. pylori colonization and eliminate its
recurrence.
147.
A patient has chronic gastritis. Which of the following organisms is most likely?
A. Escherichia coli.
B. A non-cholera Vibrio.
C. Campylobacter fetus.
D. Campylobacter jejuni.
E. *Helicobacter pylori.
148.
A person got cholera. The best treatment for cholera is
A. tetracycline
B. toxoid
C. vaccine
D. antiserum injection
E. *rehydration therapy
149.
A person got cholera. The large volume of fluid lost by diarrhea during infection with Vibrio
cholerae
A. is a consequence of fluid replacement during treatment of the disease and does not result directly
from activity of the cholera toxin
B. results from electrolytes binding to the intestinal enterocytes which upsets their water retention
capability
C. results from neurotoxic effects of the cholera toxin on the central nervous system
D. is caused when the vibrios bind to the intestinal epithelium and physically or mechanically block
the uptake of fluids by the gut epithelial cells
E. *follows activation of adenylate cyclase by cholera toxin and the subsequent effect of cyclic
AMP on water and salt balances of the host cells
150.
A person got cholera. What is the incubation period for cholerae?
A. 6 to 8 hours
B. 2 to 4 days
C. 1 to 2 weeks
D. 12 to 24 hours
E. *48 to 72 hours
151.
A stool sample is plated on standard Endo-agar plates. After overnight incubation some of the
colonies are dark pink in color, others are pale, nearly colorless. What can you conclude about the
bacteria that produced dark-pink colonies?
A. Not likely to be ‘normal flora’.
B. Non-motile.
C. Produce capsules
D. Gram-positive.
E. *Ferment lactose.
152.
A test of the patient's serum shows reactivity with Helicobacter pylori antigens. Which of the
following is true?
A. The patient's gastrin-hydrochloric homeostasis has been maintained.
B. Damage to the patient's gastric mucosa has been primarily caused by the patient's own immune
response.
C. All are true
D. The Helicobacter pylori infection most likely has nothing to do with the patient's condition.
E. *The patient will be treated with amoxicillin to eradicate H. pylori colonization and eliminate its
recurrence.
153.
A urease-positive, spiral-shaped gram-negative rod is found in gastric washings from a 29-yearold stressed-out medical student with gastritis. Which of the following is most likely tobe this organism?
A. Proteus mirabilis
B. Providencia rettgeri
C. Vibrio cholerae
D. Campylobacter jejuni
E. *Helicobacter pylori
154.
A young child develops bloody diarrhea, produced by Shigella infection. From which source
was this infection most likely to have been contracted?
A. Rare hamburger.
B. Spores present in soil.
C. Dog or cat.
D. Cow, horse, or sheep.
E. *Another child.
155.
A young man got a dysentery. Which Escherichia coli type is most like Shigella in its virulence
plasmid and mode of infection:
A. EHEC
B. EPEC
C. EAggEC
D. ETEC
E. *EIEC
156.
A young man got a dysentery. Which of the following is not true about Shigella?
A. Causes bacillary dysentery
B. Most strains are lactose nonfermenters
C. Virulence is plasmid mediated
D. The organism multiplies directly in the host cell
E. *Serotyping is based on O and H antigens
157.
A young woman got a dysentery. Humans acquire shigellosis from:
A. dogs
B. cats
C. swine
D. chickens
E. *humans
158.
A young woman got cholera. The hallmark of therapy for severe cases of cholera is:
A. antimicrobial therapy
B. outpatient treatment
C. serotherapy
D. vaccination
E. *replacement of electrolytes
159.
A young woman got cholera. To determine to which species the infectious agent belongs, the
microbiologist performs some tests on colonies cultured from stool samples. These tests include the
following EXCEPT:
A. growth on thiosulfate-citrate-bile-sucrose (TCBS) agar
B. serotyping based on O antigens
C. fermentation of sucrose
D. growth at different NaCl concentrations
E. *serotyping based on H antigens
160.
Among the Sunday night patients at the Smithville emergency room were ten young adults
suffering from severe diarrhea. All are true individuals would normally characterize themselves as being
in good health. All reported eating at a local Dairy fair during the weekend. Of the following bacterial
species the least likely to be responsible is
A.
B.
C.
D.
E.
Campylobacter fetus
Shigella flexneri
Campylobacter jejuni
Yersina enterocolitica
*Salmonella typhimurium
161.
An engineer recently returned from visiting his family in India develops severe diarrhea. He in
fact has cholera. His diarrhea is produced by a protein exotoxin secreted by Vibrio cholerae. How does
this toxin act?
A. Stimulates guanyl cyclase.
B. Inhibits guanyl cyclase.
C. ADP-ribosylates a chloride transporter.
D. Inhibits a G protein that inhibits adenyl cyclase.
E. *Stimulates a G protein that activates adenyl cyclase.
162.
Both the E. coli LT toxin and the cholera toxin
A. have an A+B subunit arrangement
B. are identical in their primary structure
C. are ADP-ribosylating toxins
D. have an enzymatic mechanism of action
E. *all answers are correct
163.
By which of the following methods Helicobacter pylori, a cause of peptic ulcers and gastric
carcinoma, is diagnosed?
A. Serology (serum) test
B. Biopsy (invasive)
C. Radioactive isotope C14 test
D. All answers are correct
E. *Bacteriological method
164.
During the procedure a biopsy of the stomach epithelium is obtained. Which observation would
suggest Helicobacter pylori as the cause of illness?
A. Biopsy shows infiltration of gastric epithelium by lymphocytes.
B. pH of stomach fluid is equal to 1 (normal), rather than decreased.
C. Ingested isotope-labeled nitrate is converted to nitrite in the stomach.
D. Bacteria are found in stomach fluid, but not in contact with the gastric epithelium
E. *Curved or spiral bacteria are seen in the biopsy after silver staining.
165.
From a 29-year-old stressed-out medical student with gastritis a urease-positive, spiral-shaped
gram-negative rod is found in gastric washings. Which of the following is most likely to be this
organism?
A. Proteus mirabilis
B. Providencia rettgeri
C. Vibrio cholerae
D. Campylobacter jejuni
E. *Helicobacter pylori
166.
Gastroenteritis caused by Campylobacter jejuni is associated with consumption of contaminated
water or foods which include the following EXCEPT:
A. milk
B. poultry
C. chicken
D. clams
E. *hamburger
167.
Gastroscopy reveals that a patient with stomach pain has a large ulceration of his gastric mucosa.
During the procedure a biopsy of the stomach epithelium is obtained. Which observation would suggest
Helicobacter pylori as the cause of illness?
A. Biopsy shows infiltration of gastric epithelium by lymphocytes.
B. pH of stomach fluid is equal to 1 (normal), rather than decreased.
C. Ingested isotope-labeled nitrate is converted to nitrite in the stomach.
D. Bacteria are found in stomach fluid, but not in contact with the gastric epithelium
E. *Curved or spiral bacteria are seen in the biopsy after silver staining.
168.
Healthy adult travelers visiting Peru are cautioned against eating uncooked vegetables and
unpeeled fruits, and against drinking unbottled water. However, they are already resistant to cholera
because of:
A. the gamma globulin shots they received before their trip.
B. their ability to avoid contaminated food due to its acidic smell.
C. their consumption of large prophylactic amounts of bicarbonates.
D. they were vaccinated
E. *a gastric barrier, due to stomach acids.
169.
If this patient had Shigellosis, the stool culture on MacConkey agar will grow:
A. glucose fermenting colonies
B. pink colonies
C. black colonies
D. lactose fermenting colonies
E. *non-lactose fermenting colonies
170.
In a 30-year old patient with fever, nausea, vomiting and bloody diarrhea, all of the following
bacteria should be considered in the diffrential diagnosis, except one:
A. Salmonella
B. Yersinia
C. ETEC
D. Shigella
E. *Campylobacter
171.
Outbreaks of diarrhea caused by species of Shigella are common in day-care centers for children
and other similar settings. What property of Shigella most enhances its spread between children?
A. Frequent presence in the upper respiratory tracts of children who are not ill
B. Ability to ferment lactose and grow in refrigerated milk.
C. Possession of an envelope resistant to disinfectants.
D. Carriage by common classroom pets such as hamsters and gerbils
E. *Resistance to stomach acid and low infectious dose.
172.
Salmonella, Yersinia, Escherichia and Shigella are put together in Bergey's Manual because they
are all
A. gram-positive aerobic cocci
B. fermentative
C. none answers are correct
D. pathogens
E. *gram-negative facultatively anaerobic rods
173.
The microbiologist is aware that the gastroenteritis outbreak is associated with the consumption
of raw seafood at a local restaurant. She considers it may be due to a number of vibrios EXCEPT:
A. V. parahaemolyticus
B. V. alginolyticus
C. V. vulnificus
D. V. cholerae non 01
E. *V. fluvialis
174.
The severe diarrhea of cholera is produced by a protein exotoxin that acts on enterocytes. Which
statement below best describes the effect of Cholera toxin?
A. Alters the actin cytoskeleton.
B. Stimulates guanyl cyclase.
C. Inactivates ribosomes.
D. Proteolytic cleavage of a specific cellular protein.
E. *Stimulates adenyl cyclase.
175.
Which following measures does not prevent Vibrio parahaemolyticus infections?
A. cook seafood for the appropriate time
B. proper refrigeration
C. vaccination
D. never return cooked seafood to the original container
E. *consume alcohol along with raw seafood
176.
Which microbe produce verotoxin?
A. S. dysenterie serotype 2
B.
C.
D.
E.
S. dysenterie serotype 4
S.dysenterie serotype 8
S.dysenterie serotype I0
*Shigella dysenterie serotype I
177.
Which one of the following organisms is MOST likely to involve invasion of the intestinal
mucosa?
A. Enterotoxigenic Escherichia coli
B. Clostridium botulinum
C. All answers are correct
D. Vibrio cholerae
E. *Shigella sonnei
178.
Young woman got cholera. Which of the following is the least accurate statement regarding
Vibrio cholerae?
A. Cholera toxin is closely related to E. coli LT (heat labile toxin).
B. Infected patients suffer from electrolyte deficiency and metabolic acidosis.
C. Fimbrial adhesions produced by the organism facilitate adherence to the brush border of
intestinal epithelial cells.
D. Can grow on alkalaine media
E. *Dark-field microscopic observation of stool from infected patients reveals large nonmotile rods.
179.
Your patient is a 30-year-old woman who was part of a tour group visiting a N. country. The day
before leaving, several members of the group developed fever, abdominal cramps, and bloody diarrhea.
Of the following, which one is the LEAST likely organism to cause this infection?
A. Salmonella enteritidis
B. Vibrio cholerae
C. Campylobacter jejuni
D. Staphylococcus aureus
E. *Shigella dysenteriae
180.
Your patient is a 30-year-old woman who was part of a tour group visiting a N. country. The day
before leaving, several members of the group developed fever, abdominal cramps, and bloody diarrhea.
Which of the following bacterium is causative agent of dysenteriae?
A. Klebsiella
B. Proteus
C. E. coli
D. Vibrio
E. *Shigella
181.
The classic cause of epidemic cholera is Vibrio cholerae O1. The designation "O1" refers to the
antigenic structure of an important component of the bacterial envelope. What is this component?
A. Capsule.
B. *Carbohydrate chains of LPS.
C. Flagella
D. Pili.
E. Teichoic acid.
182.
An engineer recently returned from visiting his family in India develops severe diarrhea. He in
fact has cholera. His diarrhea is produced by a protein exotoxin secreted by Vibrio cholerae. How does
this toxin act?
A. ADP-ribosylates a chloride transporter.
B. Inhibits a G protein that inhibits adenyl cyclase.
C. *Stimulates a G protein that activates adenyl cyclase.
D. Stimulates guanyl cyclase.
E. Inhibits guanyl cyclase.
183.
A young child develops bloody diarrhea, produced by Shigella infection. From which source
was this infection most likely to have been contracted?
A. Rare hamburger.
B. Dog or cat.
C. Cow, horse, or sheep.
D. *Another child.
E. Spores present in soil.
184.
Outbreaks of diarrhea caused by species of Shigella are common in day-care centers for children
and other similar settings. What property of Shigella most enhances its spread between children?
A. Frequent presence in the upper respiratory tracts of children who are not ill.
B. Ability to ferment lactose and grow in refrigerated milk.
C. Possession of an envelope resistant to disinfectants.
D. *Resistance to stomach acid and low infectious dose.
E. Carriage by common classroom pets such as hamsters and gerbils
185.
Which phrase best describes typical infections by Campylobacter jejuni?
A. Non-inflammatory enteritis
B. *Inflammatory enteritis
C. Systemic infection
D. Urinary tract infection
E. Meningitis
186.
A patient has chronic gastritis. Which of the following organisms is most likely?
A. Campylobacter fetus.
B. Campylobacter jejuni.
C. *Helicobacter pylori.
D. Escherichia coli.
E. A non-cholera Vibrio.
187.
Gastroscopy reveals that a patient with stomach pain has a large ulceration of his gastric mucosa.
During the procedure a biopsy of the stomach epithelium is obtained. Which observation would suggest
Helicobacter pylori as the cause of illness?
A. *Curved or spiral bacteria are seen in the biopsy after silver staining.
B. Biopsy shows infiltration of gastric epithelium by lymphocytes.
C. pH of stomach fluid is equal to 1 (normal), rather than decreased.
D. Ingested isotope-labeled nitrate is converted to nitrite in the stomach.
E. Bacteria are found in stomach fluid, but not in contact with the gastric epithelium
188.
This bacterium, although usually not considered as normal flora, frequently colonizes the
stomach and is thought to be the cause of gastric and duodenal ulcers.
A. Lactobacillus acidophilus
B. Pseudomonas aeruginosa
C. Escherichia coli
D. Vibrio cholerae
E. *Helicobacter pylori
189.
The large volume of fluid lost by diarrhea during infection with Vibrio cholerae
A. is a consequence of fluid replacement during treatment of the disease and does not result directly
from activity of the cholera toxin
B. results from electrolytes binding to the intestinal enterocytes which upsets their water retention
capability
C. is caused when the vibrios bind to the intestinal epithelium and physically or mechanically block
the uptake of fluids by the gut epithelial cells
D. *follows activation of adenylate cyclase by cholera toxin and the subsequent effect of cyclic
AMP on water and salt balances of the host cells
E. results from neurotoxic effects of the cholera toxin on the central nervous system
190.
In the pathogenesis of Helicobacter pylori what is the colonization site in the host?
A. nasal sinuses
B. *stomach
C. lower intestine
D. throat
E. respiratory tract
191.
Which of the following statements about bacterial endotoxins is true?
A. They usually act at a tissue site in the host that is removed from the site of bacterial growth.
B. *They are nonantigenic.
C. They typically have an enzymatic (specific) type of activity.
D. They can be converted into toxoids.
E. all are false
192.
Bacterial endotoxins and exotoxins both share this property.
A.
B.
C.
D.
E.
They are proteins.
They are structural components of the bacterial cell wall.
They have an enzymatic type of activity.
*They are toxic to animals.
all are false
193.
Both the cholera toxin and the E. coli LT toxin
A. have an A+B subunit arrangement
B. *are identical in their primary structure
C. are ADP-ribosylating toxins
D. have an enzymatic mechanism of action
E. all are true
194.
The main effect of E. coli and Vibrio cholerae enterotoxin on host cells of the gastrointestinal
tract that leads to the pathology of the diseases, is to
A. inhibit protein synthesis
B. *cause fluid and electrolyte imbalance
C. cleave host cell membranes
D. act as superantigens to trigger an overwhelming immunological reaction
E. initiate a localized inflammatory response in the intestine
195.
The common substrate of cholera toxin (ctx) and diphtheria toxin (dtx) is
A. NAD
B. cyclic AMP
C. *ADP ribose
D. ATP
E. elongation factor 2 (EF-2)
196.
The portion of the bacterial lipopolysaccharide (LPS) that is responsible for the toxicity of the
molecule is
A. *lipid A
B. lipoteichoic acid
C. O polysaccharide
D. Omp A
E. N-acetylglucosamine (NAG)
197.
The portion of lipopolysaccharide (endotoxin) molecule that is responsible for a bacterium’s
antigenic specificity, as well as the existence of multiple serotypes (serovars) among Gram-negative
pathogens, is
A. lipid A
B. KDO
C. *O polysaccharide
D. R antigen
E. H antigen
198.
A reason not to administer beta lactam antibiotics for a Gram-negative septicemia (blood-borne
infection), unless there is no other alternative, is
A. the antibiotic eliminates the normal flora
B. *beta lactam antibiotics are ineffective against Gram-negative bacteria
C. the lysis of bacterial cells increases the activity of bacterial LPS
D. Complement activation cannot occur in the presence of the antibiotic
E. the antibiotic suppresses the immune response necessary to eliminate the pathogen
199.
Which of the following bacteria belong/s to the family Enterobacteriaceae?
A. Shigella.
B. Salmonella.
C. Yersinia.
A. D..Proteus
D. *All are true
200.
Which of the following media is an enrichment medium for the isolation of Shigella?
A. *Selenite F broth.
B. Tetrathionate broth.
C. Alkaline peptone water.
D. Taurocholate peptone transport and enrichment medium.
E. Endo medium
201.
Which of the following bacteria is more resistant to adverse environmental conditions?
A. Shigella dysenteriae.
B. S. Flexneri.
C. *S. boydii.
D. S. sonnei.
E. Salmonella typhy
202.
Which of the following bacteria can grow in alkaline pH?
A. Lactobacilli.
B. *Vibrio cholerae.
C. Salmonella.
D. Shigella.
E. Neisseria
203.
Which of the following bacteria is negative for fermentation of mannitol?
A. *Shigella dysenteriae.
B. S. Flexneri.
C. S. boydii.
D. S. sonnei.
E. All are true.
204.
Which of the following tests can differentiate between classical and El Tor biotypes of Vibrio
cholerae?
A. Sensitivity to polymyxin B.
B. Agglutination of fowl RBCs.
C. Sensitivity to Mukerjee's group IV phage.
D. *All are true.
E. Antigenic structure
205.
Which of the following bacterium is causative agent of dysenteriae?
A. E. coli
B. Klebsiella
C. Proteus
D. Vibrio
E. *Shigella
206.
Which of the following represents a major difference between Salmonella and Shigella
infections?
A. incubation period
B. mode of transmission
C. *place of location in intestine
D. presence/absence of fever and diarrhea
E. the portal of entry
207.
The best treatment for cholera is
A. antiserum injection
B. *rehydration therapy
C. tetracycline
D. toxoid
E. vaccine
208.
Water to be used for parenteral injection must sterilized to kill living microbes and then further
purified to remove non-living bacterial components. Of those listed below, which is the most toxic?
A. *Lipopolysaccharide.
B. Polysaccharides of capsules.
C. Plasma-membrane lipids.
D. Proteins of the outer membrane.
E. Nucleic acids
209.
A stool sample is plated on standard Endo-agar plates. After overnight incubation some of the
colonies are dark pink in color, others are pale, nearly colorless. What can you conclude about the
bacteria that produced dark-pink colonies?
A. Gram-positive.
B. *Ferment lactose.
C. Not likely to be ‘normal flora’.
D. Non-motile.
E. Produce capsules
210.
A four-year-old boy was brought to the emergency room with a history of bloody diarrhea over
the preceding two days. A fecal smear contained numerous red cells and neutrophils. Stool culture on
Endo agar produced lactose-negative colonies amid colonies of ‘normal intestinal flora’. Which of the
organisms below is most likely to be the cause of his illness?
A. Enteropathogenic E. coli
B. Balantidium coli.
C. Entamoeba histolytica
D. Giardia lamblia.
E. *Shigella.
211.
The severe diarrhea of cholera is produced by a protein exotoxin that acts on enterocytes. Which
statement below best describes the effect of Cholera toxin?
A. Alters the actin cytoskeleton.
B. Inactivates ribosomes.
C. Proteolytic cleavage of a specific cellular protein.
D. *Stimulates adenyl cyclase.
E. Stimulates guanyl cyclase.
212.
A patient has a peptic ulcer. Which organism is most likely to have created this lesion?
A. Campylobacter jejuni.
B. Enterococcus faecalis.
C. Escherichia coli.
D. *Helicobacter pylori
E. Salmonella enteritidis
213.
What do endotoxins and exotoxins have in common?
A. secreted into the medium
B. *cause damage to the host
C. heat stable
D. heat resistent
E. contain polysaccharide
214.
Which of the following tests may be used to differentiate Salmonella typhi from Shigella
species?
A. glucose fermentation
B. gas production from glucose
C. *motility
D. citrate utilization
E. color of colonies on Endo medium
215.
Which of the following tests may be used to differentiate Salmonella paratyphi from Shigella
species?
A. Fermentation of glucose
B. *gas production from glucose
C. gram staining
D. citrate utilization of Simmons’ citrate agar
E. shape
216.
Helicobacter pylori is a causetive of peptic ulcers and gastric carcinoma. Which of the following
methods is used for diagnos?
A. Serology (serum) test
B. Biopsy (invasive)
C. Radioactive isotope C14 test
D. *All are true
E. All are false
217.
What is the cause of food poisoning?
A. *Campylobacter jejuni
B. Salmonella enteriditis
C. Escherichia coli
D. Clostridium botulinum
E. *All are true
218.
What is the incubation period for Shigella dysenteriae?
A. 6 to 8 hours
B. 24 to 48 hours
C. *2 to 4 days
D. 1 to 2 weeks
E. All are false
219.
The pathogenesis of which one of the following organisms is MOST likely to involve invasion of
the intestinal mucosa?
A. Vibrio cholerae
B. *Shigella sonnei
C. Enterotoxigenic Escherichia coli
D. Clostridium botulinum
E. All are true
220.
Each of the following statements concerning en-terotoxins is correct EXCEPT:
A. *Enterotoxins typically cause bloody diarrhea with leukocytes in the stool
B. Staphylococcus aureus produces an enterotoxin that causes vomiting and diarrhea
C. Vibrio cholerae causes cholera by producing an enterotoxin that activates adenylate cyclase
D. Escherichia coli enterotoxin mediates ADP-ribosylation of a G protein
E. All are true
221.
Escherichia, Salmonella, Yersinia, and Shigella are put together in Bergey's Manual because they
are all
A. pathogens
B. *gram-negative facultatively anaerobic rods
C. gram-positive aerobic cocci
D. fermentative
E. all are false
222.
A 6 years old child, who goes to primary school, has a whooping cough. What preparation is
used for the prophylaxis of whooping cough for children?
A. TABTte
B. ADT
C. AD
D. Human immunoglobulin
E. *Pertussis-diphtheria-tetanus vaccine
223.
7 years old child is in the infectious department with a diphtheria of pharynx. Material, which
was taken from greyish film on tonsils, was inoculated Klauberg medium. In 2 days there were typical
colonies of С. diphtheriae. What next stage of examination must be done?
A. To examine biochemical properties of microbes
B. To examine toxigenic properties of microbes
C. To examine the production of urease, nitrate reductase
D. To stain microbes by Ziehl-Neelsen technique
E. *To examine bacterial toxigenicity and examine cystinase production
224.
A 2 year old child presented with a membrane in the mouth. Within 24 hrs a culture report is
needed. The preferred medium is ____
A. Blood agar
B. Lowenstein-Jensen medium
C. Tellurite agar
D. Sugar agar
E. *Loeffler medium
225.
A 55-year-old man has a two month history of fever and weight loss. He has recently begun to
cough up yellow-green sputum, sometimes with blood in it. X-rays show evidence of lung inflammation
and damage. He is given a PPD skin test. Which statement below about the results of PPD testing is
most accurate?
A. A positive PPD test indicates active tuberculosis.
B. A PPD test may yield a false-positive result in a person with advanced disease [who may be
anergic].
C. A PPD test can cause a person (previously un-exposed to Mycobacterium tuberculosis) to covert
to PPD-positive status, and so can be performed only once on a patient.
D. A positive PPD test indicates high level of immunity.
E. *A PPD test may produce a false-negative (or weakly-positive) result if the patient has impaired
cell-mediated immunity.
226.
A 6 years old child has paroxysmal cough during 3 days. Whooping cough was diagnosed. What
tested material for examination is it needed to take first to confirm a diagnosis?
A. Patient’s blood
B. *Smear from the posterior wall of the throat
C. Pus
D. Patient’s serum
E. Vomiting masses
227.
A baby was born in a maternity hospital. What vaccine is prescribed him before discharge from a
hospital?
A. Vaccine against whooping cough, diphtheria, and tetanus
B. Attenuated poliomyelitis vaccine
C. EV 76 vaccine
D. Attenuated influenza vaccine
E. *BCG
228.
A child has a common cold which progresses to severe pharyngitis. Pharyngeal exudate forms a
tough membrane difficult to remove without causing bleeding. Culture of a throat swab on selective
tellurite agar produces abundant black colonies. Other cultures produce only normal flora. Which
organism is most likely to have caused this infection?
A. Actinomyces israelii.
B. Bordetella pertussis.
C. Candida albicans.
D. Mycobacterium avium/intracellulare.
E. *Corynebacterium diphtheriae.
229.
A child has severe pharyngitis. Pharyngeal exudate forms a tough 'membrane', difficult to
remove without causing bleeding. Culture of a throat swab on selective tellurite agar produces abundant
black colonies. Other cultures produce only normal flora. Which organism below is most likely to have
caused this infection?
A. Streptococcus pneumoniae.
B. Haemophilus influenzae.
C. Bordetella pertussis.
D. Mycobacterium avium/intracellulare
E. *Corynebacterium diphtheriae.
230.
A girl, 7 years of old was admitted to the hospital with the high temperature, throat pain general
weakness. A doctor suspected diphtheria and took material from pharynx for isolation of pure culture of
Corynebacterium. What test can confirm the diagnosis of diphtheria?
A. Examination of volutin granules
B. Examination of cystinase production
C. Examination of hemolytic properties
D. Susceptibility to phages
E. *Examination of bacterial toxigenicity
231.
A growth of tuberculosis bacteria on nutrient media takes a place in 3 weeks, sometimes in 2-3
months. But express technique for there cultivation, Prices and Shkolnikov’s methods may be used. In
what time is it possible to get growth of tuberculosis microcultures?
A. 3-4 days
B. 20-30 days
C. over 40 days
D. over 50 days
E. *7-10 days
232.
A man, 40 years old has chronic kidneys infection. During examination of urine acids fast rodshaped microbes were revealed. They did not grow on simple nutrient media, but on LoewenstainJensen medium in a few weeks they formed dry yellowish colonies. What group of microorganisms
could cause his disease?
A.
B.
C.
D.
E.
Chlamidia
Mycoplasma
Trichomonas
Gardnerella
*Mycobacteria
233.
A microbiologist put a few drops of 1% Ziehls phenol fuchsine on a paper which covers a smear
from patients sputum, heat it until steam rose. He repeated this procedure three times. Then took off a
paper, put a smear in 5 % sulphuric acid, washed with water and stained by methylene blue. What
microbes can be examined by this technique?
A. S. aureus
B. S. pneumoniae
C. S. viridans
D. K. pneumoniae
E. *M. tuberculosis
234.
A mother with a 5 years old girl, who has a cough and flu-like state during 2 weeks, visited the
doctor. Last time a cough increased, paroxysmal cough appeared. A doctor diagnosed whooping-cough.
What factors do determine virulence of Bordetella pertussis?
A. Exotoxin
B. Pili
C. Hyaluronidaze
D. Histamin-sensitizing factor
E. *Thermolabile toxin
235.
A patient has cough with discharges of sputum. During microscopic examination after staining
this smear by Ziehl-Neelsens technique dark blue cocci, which form irregular clasters and rod-shaped
red bacteria were revealed. What microorganisms may be a reason of disease?
A. Actinomyces bovis
B. Staphylococcus aureus
C. E.coli
D. Corynebacterium diphtheriae
E. *Mycobacterium tuberculosis
236.
A sick child was tested by Mantouxs test. In 24 hours there were tumidity, hyperemia and
painfulness in the place of allergen injection. What basic mechanisms do provide this reaction of a
body?
A. Granulocytes, T- lymphocytes, and Ig G.
B. Plasma cells, T-cell, and lymphokines
C. B-lymphocytes, IgM
D. Macrophages, B-lymphocytes, and monocytes
E. *Mononuclear cells, T-cell, and lymphokines
237.
According to epidemiological indication in preschool it is necessary to make vaccination against
a whooping cough. What preparation may be used?
A. live attenuated pertussis vaccine
B. BCG vaccine
C. Human immunoglobulin
D. Killed pertussis vaccine
E. *Pertussis-diphtheria-tetanus vaccine
238.
After making Mantouxs test in a child of 4 years old in 72 hours a reddening of the skin in the
place of injection of tuberculin is not observed. What does this result testify?
A. A child has tuberculosis
B. A child is vaccinated against tuberculosis
C. A child is a carrier of tuberculosis bacteria
D. A child is infected by tuberculosis bacteria
E. *A child is not vaccinated against tuberculosis
239.
After staining of patient’s sputum by Ziehl-Neelsen technique red rod-shaped bacteria were
revealed. The first signs of bacterial growth appeared in 17 days. What bacteria may be there in the
smear?
A. Yersinia pseudotuberculosis.
B. Histoplasma dubrosii
C. KlРµbsiella rhinoscleromanis
D. Coxiella burnetii
E. *Mycobacterium tuberculosis
240.
After vaccination of babies by BCG vaccine immunity to tuberculosis lasts until there are living
bacteria of vaccine strain in an organism. What is correct name of such type of immunity?
A. Type specific
B. Humoral
C. Species inherited
D. Natural
E. *Non-sterile
241.
Bacteriological laboratory urine from a patient with an initial diagnosis of kidneys tuberculosis
must be investigated in bacteriological laboratory. What method of diagnosis is it better to utilize?
A. Bacteriological
B. Bacterioscopy
C. Serological
D. Allergic
E. *Biological
242.
Bordets nutrient medium is utilized for isolation of causative agent of whooping cough from
clinical material. What component is not necessarily included in its composition?
A. Glycerol
B. Potato starch
C. Blood
D. *РҐ-factor
E. all are true
243.
9 years old has diphtheria of pharynx. What was the way of diphtheria transmission?
A. Fecal-oral
B. *Air born
C. Sexual
D. Contact
E. No way
244.
Diphtheria was diagnosed in 4 years old child. What preparation is it necessary to inject first of
all?
A. TABTe.
B. Diphtherial toxoid
C. Vaccine against whooping cough, diphtheria, and tetanus
D. Vaccine against diphtheria and tetanus
E. *Diphtherial antiserum.
245.
During examination of bacterial carriers in the kindergarten one nurse showed the presence of
Corynebacterium in her throat. The production of toxin by Corynebacterium diphtheriae was checked.
It did not produce exotoxin. What test was used for examination of toxigenicity?
A. Agglutination test
B. Ring precipitation test
C. *Precipitation test in gel
D. Complement fixation test
E. Immunofluorescence test
246.
During examination of patient’s sputum, which was inoculated by Prices technique, rod-shaped
bacteria appear as plaits. What substance from tuberculosis bacilli does form such pictures?
A. Tuberculin.
B. *Cord-factor
C. Phtionic acid (phosphatide).
D. Fatty acids.
E. PPD.
247.
During examination of patient’s sputum, which was stained by Ziehl-Neelsen, method
microbiologist saw red thin, long rods appeared as plaits. What method of cultivation was utilized?
A. Loefllers
B. Drygalskys
C. *Prices
D. Mantoux
E. Kalmett-Guerin
248.
During the examination child 6 years of old a doctor noticed greyish film on the surface of
tonsils. During the attempt of it’s deleting moderate bleeding appeared. During bacterioscopy after
Neissers staining: rods display club-shaped swellings, volutin granules. What symptoms will appear in a
child in the nearest days, if specific treatment will not be prescribed?
A. Oedema of lungs
B. *Toxic lesion of cardiac muscle and kidneys
C. Paroxysmal cough
D. Papular rashes on a skin
E. Disorders of digestion
249.
Every year pediatricians use Mantouxs allergic for checking of the children and teenagers. What
is the aim of this test?
A. Treatment of tuberculosis
B. Prophylaxis of tuberculosis
C. Vaccination
D. *A selection of children for revaccination by BCG vaccine
E. No correct answer
250.
Five days old boy has planned immunization with BCG vaccine. In 7 years doctor prescribed
repeated immunization with the same vaccine. What examination was the basis of such doctor’s
decision?
A. Examination of antimycobacterial antibodies
B. *Skin allergic test
C. Medical and genetic examination
D. Bacterioscopy of childs sputum
E. X-ray examination of the lungs
251.
Five years old child was admitted to the hospital with a diagnosis of diphtheria of pharynx.
Material, which was taken from greyish film on tonsils, was inoculated Klaubergs medium. What are
there properties of Corynebacterium colonies on this medium?
A. Colonies are convex, with even edges, colorless
B. Colonies are rounded, concave in a center, white
C. Colonies are protuberant, viscid, remind a shagreen skin, grey
D. Colonies are rosette-like, a surface is knobby, yellow
E. *Colonies are grey, round, rosette-like
252.
For a patient with suspicion of diphtheria microbiologist found rod-shaped bacteria with granules
of volutin? What method might be used for staining?
A. Ziehl-Neelsen
B. Gram
C. Burry-Gins
D. Anjesky
E. *Neisser
253.
For diagnosis of tuberculosis infection among schoolboys it is necessary to make allergic
intracutaneous Mantouxs test. What preparation may be used for the test?
A. *Tuberculin
B. BCG vaccine.
C. STI vaccine.
D. Anthraxin.
E. Brucellin
254.
For examination of Corynebacterium diphtheriae toxigenicity these microbes were inoculated on
the agar and paper strip impregnated with antitoxic serum was put on the surface of gel. After
incubation precipitation lines between the bacterial plaques and paper strip appeared in agar. What
serologic test was used?
A. *Precipitation test in gel
B. Kumbss test
C. Agglutinations test
D. Ring precipitation test
E. Opsonization test
255.
For rapid cultivation of Mycobacterium tuberculosis Pryces and Shkolnikovas methods are used.
What factor of virulence may be revealed by this technique?
A. Lecithinase
B. Capsule formation
C. *Cord-factor
D. Neuraminidase
E. DNA-ase
256.
From nasal part of pharynx of child of 4 years old rod-shaped microorganisms were isolated.
According to their morphological and biochemical properties they were identical to Corynebacterium
diphtheriae, but did not produce exotoxin. By what way can this microorganism become toxigenic?
A. Chromosomal mutation.
B. Cultivation on a tellurate medium
C. Passages through the organism of susceptible animals
D. Cultivation in a presence of antitoxic serum.
E. *Phage conversion
257.
In 1874 G. Hansen described the causative agent of serious human infectious chronic disease,
which has very long incubation. Specific infiltrates – lepromas are formed in patients. What family
does the causative agent of disease belong to?
A. Corynebacteriaceae
B. Enterobacteriaceae
C. Actinomycetaceae
D. *Mycobacteriaceae
E. Rickettsiaceae
258.
In 6 years old child with paroxysmal cough mucous from oropharynx was taken. This material
was inoculated on glycerin-potatoes agar. In 72 hrs of cultivation at 37 C there were small greyish
convex, and glistening, resembling globules of mercury appeared. What causative agent did cause this
disease?
A. Haemophilus influenzae
B. Staphylococcus aureus
C. Neisseria meningitidis
D. *Bordetella pertussis
E. Mycobacteria tuberculosis
259.
In 8 years old child active tuberculosis process was suspected. Diagnostic Mantouxs reaction
was made. In 30 minutes after the injection there was an insignificant erubescence in the place of
injection. In 24 hours the phenomenon of dermahemia disappeared. What does the result of reaction
testify to?
A. Postvaccinal immunity
B. Active tubercular process.
C. *A reaction is negative
D. A tuberculosis process is occult
E. A reaction is positive
260.
In a 6 years old child active tuberculosis process was suspected. Diagnostic Mantouxs reaction
was made. What immunobiological preparation was used?
A. Pertussis-diphtheria-tetanus vaccine.
B. BCG vaccine.
C. *Tuberculin.
D. Tulyarin.
E. No correct answer
261.
In a child with the suspicion of diphtheria a swab from the mucus membrane of pharynx was
taken. After staining by Loeffers method dark-blue granules of volutin were revealed in bacteria. What
value does their examination have?
A. *Diagnostic
B. Treatment
C. Prophylactic
D. None of them
E. All answer are correct
262.
In a maternity hospital it follows newborn to execute an inoculation against tuberculosis. What
preparation must be here utilized?
A. Vaccine of EV.
B. Vaccine of STI
C. *Vaccine of BCZH
D. Vaccine of AKDP
E. Tuberculin
263.
In a smear from a patients tonsils with suspicion of diphtheria blue rod-shaped bacteria display
terminal club-shaped swellings, which stained more intensely at their end were revealed. What method
of staining was utilized?
A. Gram
B. Burry
C. Giemsa
D. *Loeffler
E. Neisser
264.
In an infectious department there is a girl, 10 years of old with a diagnosis diphtheria of
pharynx”. Toxigenic strain of Corynebacterium diphtheriae was isolated. How can you examine the
strain toxigenicity?
A. By agglutination test
B. By complement fixation test
C. *By precipitation test in a gel
D. By indirect haemagglutination test
E. By flocculation test
265.
In kindergarten whooping cough was diagnosed in 3 children. In what clinical periods of
whooping cough they may be most contagious?
A. Latent period
B. Paroxysmal period
C. *Catarrhal period
D. Regenerative period
E. Period of reconvalescence
266.
In tonsils smear yellow brown rod-shaped bacteria with dark blue granules of volutin were
revealed. What method of staining was utilized?
A. Gram
B. Anjesky
C. Loeffler
D. *Neisser
E. Ziehl-Neelsen
267.
Leprosy was suspected in a patient. What skin-allergic test can confirm this diagnosis?
A. Dick
B. Moloni
C. *Mitsuda
D. Kumbs
E. Shick
268.
Mantouxs allergic test was made in young man of 16. Test was negative. What is the most
rational tactics of doctor?
A. *To make vaccination by BCG vaccine
B. To repeat a test in month
C. To make serologic diagnosis of tuberculosis
D. Quickly to isolate this young man from a collective
E. To make rapid diagnosis of tuberculosis by Prices method
269.
Mantouxs test is a specific diagnostic test. The results of allergic test we estimate in 72 hours.
What is positive result?
A. *diameter of papule 5 mm and more
B. diameter of hyperemia 5-10 mm
C. diameter of papule 3-7 mm
D. diameter of hyperemia 7-15 mm
E. diameter of hyperemia 8-14 mm
270.
On the tonsils of boy of 12 which got the planned vaccination by pertussis-diphtheria-tetanus
vaccine the microorganisms identical to Corynebacterium diphtheriae according to their morphological
and biochemical signs were isolated. The precipitation test in gel with an antitoxic serum gave positive
result. What form of infectious process can this causative agent cause?
A. *Asymptomic bacterial carriage
B. Ligh non toxic form of disease
C. Toxic complicated form of disease
D. Chronic disease with lesion of internal organs
E. Persisting infection
271.
Pathogenesis of considerable part of infectious diseases is related to the action of bacterial
protein toxins, which have selective action on different organs and tissues of the body. Show, what
toxins is the strongest cellular poison and blocks the synthesis of protein:
A. Staphylococcal toxin
B. *Diphtherial histotoxin
C. Tetanospasmin
D. Botulinum neurotoxin
E. Cholerae enterotoxin
272.
Patient has initial diagnosis of lung tuberculosis. What nutrient medium may be used for
isolation of mycobacteria:
A. glycerin-potatoes agar
B. *Loewenstein-Jensen medium
C. salt-salt agar
D. blood agar
E. Ploskirev medium
273.
Patients sputum was sent to a laboratory. What method of staining does it follow to utilize for the
examination of causative agents of tuberculosis?
A. Gram
B. Giemza-Romanovsky
C. Gins-Burry
D. *Ziehl-Neelsen
E. Neissers
274.
Seven years old child has fever and paroxysmal cough. Similar symptoms were observed in a
senior brother month ago. There may be whooping cough. What method is it possible to use for
retrospective diagnosis of this disease?
A. *Serological
B. Bacteriological
C. Biological
D. Morphological
E. Allergic
275.
The child has diagnosis of diphtheria of pharynx. The clinical diagnosis is confirmed by
bacteriologic examinations: toxigenic Corynebacterium diphtheria was isolated. What preparations do
apply for specific treatment?
A. Antibiotics
B. Sulfonamides
C. Toxoid
D. *Antitoxic serum
E. NO correct answer
276.
The presence of lipid cord factor in a cell wall of tuberculosis bacilli leads to that this
microorganism is absorbed by phagocytes, but do not kill. What term does determine this property of
microorganism most exactly?
A. Pathogenicity
B. Invasiveness
C. *Aggressiveness
D. Colonisational resistance
E. Toxigenicity
277.
The toxigenicity of causative agents of diphtheriae is directly associated with determinants of
toxigenicity (tox+-genes). Where do these genes localize?
A.
B.
C.
D.
E.
*In DNA of temperate phages
In Hly plasmids
In Ent plasmids
In DNA of causative agents
In transposones
278.
There is 7 years old child with a diagnosis of diphtheria of pharynx. What tested material must
be taken for isolation of causative agent and confirmation of diagnosis?
A. Patients blood
B. Patients serum
C. *Swab from the pharynx
D. Sputum
E. Pus
279.
There is a bacteriological method for laboratory diagnosis of diphtheria. For cultivation of РЎ.
diphtheriae it is necessary to know the some bacterial properties. According to the type of respiration is
РЎ. diphtheriae:
A. Obligate aerobe
B. *Facultative anaerobe
C. Obligate anaerobe
D. Microaerophilic bacterium
E. Capneic bacterium
280.
There is a bacteriological method for laboratory diagnosis of diphtheria. For cultivation of РЎ.
diphtheriae it is necessary to know the some bacterial properties. What nutrient media it is necessary to
use for cultivation of Corynebacterium diphtheriae?
A. Serum agar
B. *blood agar, blood tellurite agar
C. sugar MPB, sugar MPA
D. yolk-salt agar
E. Endo, Ploskirev
281.
When doctor examined a child of 6 years old he revealed the greyish film on the tonsils. He took
this film, stained by Neisser's technique. What morphological feature was most substantial for
confirmation that these microbes are Corynebacteria?
A. Localization of microbes in macrophages
B. *The presence of volutin granules at the ends of microbes
C. Presence of spores, their diameter is more then diameter of the cell
D. Presence of flagella
E. Presence of capsule
282.
Which line below correctly pairs a bacterial group or species with an antibiotic that currently
inhibits enough of its members to be used against it, before results of sensitivity testing are received?
Many Bacteria are sensitive to
A. Enterobacteriaceae, Penicillin G
B. Staphylococcus aureus, Penicillin G
C. *Mycobacterium tuberculosis, Isoniazid
D. Obligate anaerobes, Aminoglycosides
E. Obligate aerobes, Metronidazole
283.
Which of the following is spread by close person-to-person contact through the inhalation of
infectious aerosols and infects a third of the worlds population according to the World Health
Organization (WHO)?
A. M. leprae
B. M. avium-intracellulare
C. *M. tuberculosis
D. E.coli
E. S. paratyphi A
284.
Which of the following is spread by person-to-person contact, has fallen in prevalence by almost
90% since 1985, and is endemic in armadillos?
A. *M. leprae
B. M. avium-intracellulare
C. M. tuberculosis
D. M. paratuberculosis
E. M. scrofulaceum
285.
Which of the following primarily affects immunocompromised patients, has not shown personto-person transmission, is acquired through ingestion of contaminated water or food, is seen most
commonly in countries where tuberculosis is less common?
A. M. leprae
B. *M. avium-intracellulare
C. M. Tuberculosis
D. M. paratuberculosis
E. M. scrofulaceum
286.
Whooping cough is acute mainly child's infectious disease which is characterized by catarrhal
inflammation of respiratory tracts and attacks of paroxysmal cough. Virulence of Bordetella pertussis is
determined by all the factors, EXCEPT:
A. Pertussis thermolabile exotoxin
B. Pili
C. Histamin-sensitizing factor
D. Endotoxin
E. *Capsule formation
287.
A patient is diagnosed with Clostridium difficile colitis. Which item would represent a known
risk factor for such infections?
A. *Been treated with antibiotics.
B. Consumed unpurified water.
C. Visited the southwestern United States.
D. Eaten undercooked fried rice.
E. Been in contact with livestock
288.
ANSWER:A
289.
A 22-year-old develops an abscess in his peritoneum following rupture of his appendix. Gram
stain of exudate from his foul-smelling abscess reveals numerous polymorphonuclear leukocytes, Grampositive cocci, Gram-positive rods, and Gram-negative rods. Aerobic culture of the exudate at 37oC on
blood and MacConkey agar yields only Enterococci. Which of the bacteria below is most likely to be
the Gram-negative rods seen in the stained smear?
A. Pseudomonas aeruginosa.
B. Proteus mirabilis.
C. Klebsiella pneumoniae.
D. Prevotella melaninogenica.
E. *Bacteroides fragilis.
290.
A 61-year-old diabetic man is admitted to the hospital for severe pain in his right leg; the
diagnosis is obstruction of the femoral artery. The affected area of the leg is painful, red, and swollen.
During the next 12 hours the swelling increases markedly, the skin of the leg becomes discolored, and
fluid-filled blisters appear on the skin. Gram stain of fluid aspirated from a blister reveals large Grampositive rods. Which organism below is most likely to have caused this infection?
A. Clostridium botulinum.
B. Clostridium difficile.
C. *Clostridium perfringens.
D. Clostridium tetani.
E. Listeria monocytogenes.
291.
The young man was injuring in car accident. The affected area of the leg is painful, red, and
swollen. During the next 12 hours the swelling increases markedly, the skin of the leg becomes
discolored, and fluid-filled blisters appear on the skin. Gram stain of fluid aspirated from a blister
reveals large Gram-positive rods. Which organism below is most likely to have caused this infection?
A. Clostridium botulinum.
B. *Clostridium perfringens.
C. Clostridium difficile.
D. Clostridium tetani.
E. Listeria monocytogenes.
292.
Bacteroides fragilis is isolated from an abdominal abscess. Which phrase below best describes
infections like this one?
A.
B.
C.
D.
E.
293.
A.
B.
C.
D.
E.
294.
A.
B.
C.
D.
E.
295.
A.
B.
C.
D.
E.
296.
A.
B.
C.
D.
E.
297.
A.
B.
C.
D.
E.
298.
A.
B.
C.
D.
E.
299.
A.
B.
C.
D.
E.
300.
A.
B.
C.
D.
E.
301.
A.
B.
C.
*Other species of bacteria are also often present.
Initiated by ingestion of spores.
Can be successfully treated with aminoglycosides alone.
Contracted by the respiratory route.
Sexually-transmitted.
Both the botulinum toxin and the tetanus toxin
A. are produced by Bacillus anthracis
act in the central nervous system
*act in the peripheral nervous system
are Zn++ dependent protease enzymes
two of the above
The clostridial invasin that dissolves the framework of muscle is
botulinum toxin
tetanus toxin
*hyaluronic acid
neuraminidase
collagenase
Both the botulinum toxin and the tetanus toxin are
superantigens
enterotoxins
adenylate cyclase enzymes
*protease enzymes
all are false
The common mode of action of the tetanus and botulinum toxins is to
*block the release of neurotransmitters across a neural synapse
up-regulate the production of cAMP in affected cells
cause the ADP ribosylation of neuron gangliosides
block protein synthesis in target cells
cleave neuraminic acid in the intercellular space
Passive immunity to tetanus in a susceptible host would be accomplished by
recovery from the disease tetanus
injection with tetanus toxin
injection with tetanus toxoid (as in the DPT vaccine)
*administration of donor’s antitetanus immunoglobulin
two of the above
Active artificial immunity to tetanus is accomplished by
tetanus antitoxin (antiserum) administration
*vaccination with tetanus toxoid
recovery from the disease tetanus
all are true
all are false
Antitoxic therapy is useful in:
gas gangrene.
diphtheria.
tetanus
* all are true
all are false
Typical drumstick appearance of bacilli is observed in:
Clostridium perfringens.
C. tetani.
С. botulinum.
*C. histolyticum.
C. difficilae
Bacterial genus/genera of medical importance which produce Endopores is/are:
Staphylococcus
all are true
*Clostridium.
302.
303.
304.
305.
306.
307.
308.
309.
310.
311.
D. Bacteroides
E. all are false
Which of the following exotoxins is most toxic?
A. *Botulinum toxin.
B. Tetanus toxin.
C. Diphtheria toxin.
D. Cholera toxin.
E. Shigella toxin
Infective-toxic type of food poisoning is caused by:
A. *Clostridium perfringens.
B. Salmonella Enteritidis.
C. Staphylococcus aureus.
D. Salmonella Dublin.
E. Yeasts
The causative agent/s of gas gangrene is/are:
A. Clostridium perfringens.
B. C. novyi.
C. С. septicum.
D. C. histolyticum
E. *all are true.
Which of the following properties is/are characteristic of tetanospasmin?
A. It is a heat-labile protein.
B. It is a neurotoxin.
C. It can be toxoided.
D. It is exotoxin
E. * all are true
Which of the following exotoxins resembles strychnine in its effect?
A. Botulinum toxin.
B. *Tetanus toxin.
C. Diphtheria toxin.
D. All are false
E. All are true
Each of the following is a typical property of obligate anaerobes EXCEPT:
A. *They generate energy by using the cytochrorne svstem
B. They grow best in the absence of air
C. They lack superoxide dismutase
D. They lack catalase
E. They grow in Kitt-Tarozi medium
What is the usual habitat of Endopore-forming bacteria that are agents of disease?
A. the intestine of animals
B. *soil
C. water
D. foods
E. dust
Most Bacillus species are
A. true pathogens
B. opportunistic pathogens
C. *nonpathogens
D. commensals
E. saprophyticus
Many clostridial diseases require a/an conditions for their development.
A. *anaerobic
B. aerobic
C. living tissue
D. low-pH
E. alkaline pH
Clostridium perfringens causes
A.
B.
C.
D.
E.
*myonecrosis, food poisoning
enterocolitis, haemorrhagic syndrom
antibiotic-induced colitis
All are true
No correct answer
312.
The action of tetanus exotoxin is on the
A. neuromuscular junction
B. sensory neurons
C. nucleus of hypocamp
D. cerebral cortex
E. *spinal interneurons
313.
Which infectious agent cause pseudomembranous collitis?
A. Mycobacterium tuberculosis
B. Corynebacterium diphtheriae
C. Mycobacterium leprae
D. Clostridium difficile
E. *Shigella sonnei
314.
Which infectious agents cause food poising?
A. Bacillus anthracis
B. Clostridium tetani
C. *Clostridium perfringens
D. Streptococcus pyogenes
E. all of these
315.
A child at-risk for Tetanus is treated with Tetanus immune globulin (human). What is a major
advantage of this method for immunization over the use of Tetanus toxoid?
A. Poses a reduced risk of serum sickness.
B. Provides longer-lasting immunity.
C. *Provides protection more rapidly.
D. Results in higher antibody titer.
E. Also provides secretory IgA for mucosal immunity.
316.
A child under treatment for leukemia is treated with Tetanus immune globulin (human). Which
phrase best describes the immunity that is produced?
A. Innate and specific.
B. Innate and humoral.
C. Innate and cell-mediated.
D. *Acquired and humoral.
E. Acquired and cell-mediated.
317.
A 20-year-old student has a deep laceration. He received the standard four-doses of DiphtheriaPertussis-Tetanus immunizations in infancy, and a booster at age 5, but has had no anti-Tetanus
immunization since. Which of the following would it be most appropriate to administer?
A. Tetanus toxoid.
B. Tetanus anti-toxin (equine).
C. Tetanus immune globulin (human).
D. *Both Tetanus toxoid and Tetanus immune globulin (human).
E. Both Tetanus toxoid Tetanus anti-toxin (equine).
318.
A ten-year-old girl has dirty, crushing, wounds, received when she fell from a motorcycle. She
has never been immunized against Tetanus. Which of the following should you administer?
A. Tetanus immune globulin (human) Tetanus toxoid
B. Tetanus anti-toxin (equine) Tetanus toxoid
C. Tetanus toxoid Tetanus immune globulin (human)
D. Tetanus toxoid plus Tetanus immune globulin (human),
E. *Tetanus toxoid plus Tetanus immune globulin (human
319.
A patient has rapidly spreading soft-tissue infection with gas in infected tissue. Fluid from a
blister contains many large Gram-positive rods which grow on sheep blood agar anaerobically but not
aerobically. Which pathogen is most consistent with these findings?
A. Bacillus anthracis.
B. Bacillus cereus.
C. Clostridium difficile.
D. *Clostridium perfringens.
E. Listeria monocytogenes.
320.
The spastic paralysis of Tetanus is the effect of a protein exotoxin. Which phrase below best
describes the process directly inhibited by Tetanus toxin?
A. Synthesis of neurotransmitter.
B. Transport of neurotransmitter into vesicles.
C. Calcium influx required for neurotransmitter release.
D. *Docking and fusion of neurotransmitter vesicles with the synaptic membrane.
E. Binding of neurotransmitter molecules to their receptors
321.
An infant is brought to the emergency room, cyanotic and with poor muscle tone. Which
condition is most likely given these findings?
A. Antibiotic-associated colitis.
B. Diphtheria.
C. Anthrax.
D. *Botulism.
E. Tetanus.
322.
A patient has an abscess from which Bacterioides fragilis is isolated. Which condition is most
likely to have facilitated infection by this organism?
A. Treatment with trimethoprim/sulfa.
B. *Tissue ischemia.
C. Presence of neutrophils.
D. Antibiotic treatment for another bacterial infection.
E. Colonization of the large intestine with spores of this organism.
A. A 50-year-old woman was treated for cystitis [caused by E. coli] with an oral broad-spectrum antibiotic.
Three weeks later she developed abdominal pain and diarrhea. A stained smear of stool contained many
neutrophils. Cultures for bacterial pathogens were negative. A serological test of stool for Clostridium
difficile toxin was positive. Which of the following is most likely to have been the immediately
predisposing cause of this patient’s C.difficile infection?
A. Colonization of her large intestine by antibiotic-resistant E. coli.
B. *Alteration of her intestinal flora by antibiotic treatment.
C. An allergic response to her antibiotic treatment.
D. Acquisition of an antibiotic-resistance plasmid (R-Factor) by C. difficile.
E. All are true
323.
Which of the following members of the Clostridium family causes pseudomembranous colitis?
A. Clostridium tetan
B. *Clostridium difficile
C. Clostridium botulinum
D. Clostridium perfringens
E. Listeria monocytogenes.
324.
Which of the following methods is used to help clear an anaerobic infection?
A. Removal of dead tissue
B. Drainage of infected area
C. Oxidizing agents/hyperbaric chambers
D. *All are true
E. None of answers
325.
What causes gas gangrene?
A. *Clostridium perfringens
B. Leptospira interrogans
C. Staphylococcus aureus
D. Escherichia coli
E. Clostridium tetan
326.
Each of the following organisms is an important cause of urinary tract infections EXCEPT:
A. Escherichia coli
B. Proteus mirabilis
C. Klebsiella pneumoniae
D. *Bacteroides fragilis
E. All are true
327.
The MOST important protective function of the antibody stimulated by tetanus immunization is
A. To opsonize the pathogen (Clostridium tetani)
B. To prevent growth of the pathogen
C. To prevent adherence of the pathogen
D. *To neutralize the toxin of the pathogen
E. All are true
328.
Your patient is a 70-year-old man who under went bowel surgery for colon cancer 3 days ago.
He now has a fever and abdominal pain. You are concerned that he may have peritonitis. Which one of
the following pairs of organisms is MOST likely to be the cause?
A. *Bacteroides fragilis and Klebsiella pneumoniae
B. Bordetella pertussis and Salmonella enteritidis
C. Actinomyces israelii and Campylobacter jejuni
D. Clostridium botulinum and Shigella dysente-riae
E. All are true
329.
Each of the following statements concerning Bacteroides fragilis is correct EXCEPT:
A. B. fragilis is a gram-negative rod that is part of the normal flora of the colon
B. *fragilis forms Endopores, which allow it to survive in the soil
C. The capsule of B. fragilis is an important virulence factor
D. B. fragilis infections are characterized by foul-smelling pus
E. All are true
330.
Five days ago a 65-year-old woman with a lower urinary tract infection began taking ampicillin.
She now has a fever and severe diarrhea. Of the organisms listed, which one is MOST likely to be the
cause of the diarrhea?
A. *Clostridium difficile
B. Bacteroides fragilis
C. Proteus mirabilis
D. Bordetella pertussis
E. All are true
331.
Each of the following statements concerning exotoxins is correct EXCEPT:
A. Some strains of Escherichia coli produce an enterotoxin that causes diarrhea
B. Cholera toxin acts by stimulating adenylate cyclase
C. Diphtheria is caused by an exotoxin that inhibits protein synthesis by inactivating an elongation
factor
D. *Botulism is caused by a toxin that hydrolyzes lecithin (ledthinase), thereby destroying nerve
cells
E. All are true
332.
Each of the following statements concerning Clostridium perfringens is correct EXCEPT:
A. It causes gas gangrene
B. It causes food poisoning
C. It produces an exotoxin that degrades lecithin and causes necrosis and hemolysis
D. *It is a gram-negative rod that does not ferment lactose
E. All are true
333.
Each of the following statements concerning Clostridium tetani is correct EXCEPT:
A. It is a gram-positive, spore-forming rod
B. Pathogenesis is due to the production of an exotoxin that blocks inhibitory neurotransmitters
C. *It is a facultative organism; it will grow on a blood agar plate in the presence of room air
D. Its natural habitat is primarily the soil
E. All are true
334.
Which one of the following statements concern ing immunization against diseases caused by
Clostridia is CORRECT?
A. Antitoxin against tetanus protects against botulism as well, because the two toxins share
antigenic sites
B. Vaccines containing alpha toxin (lecithinase) are effective in protecting against gas gangrene
C. The toxoid vaccine against Clostridium difficile infection should be administered to
immunocompromised patients
D. *mmunization with tetanus toxoid induces effective protection against tetanus toxin
E. All are true
335.
Each of the following statements concerning wound infections caused by Clostridium perfrin
gens is correct EXCEPT:
A. An exotoxin plays a role in pathogenesis
B. Gram-positive rods are found in the exudate
C. *The organism grows only in human cell culture
D. Anaerobic culture of the wound site should be ordered
E. All are true
336.
Closcridium and Bacillus are unique among most bacteria in that they
A. are acid-fast
B. are Gram positive
C. *produce Endopores
D. do not have teichoic acids
E. are mesophiles
337.
Choose method of staining of bacterial spores, which are formed by C. tetani and C. botulinum:
A. Staining by mеthylene blue
B. *Staining by Aujesko’s method
C. Staining by Ziehl-Neelsen’s method
D. Staining by Gram method
E. Staining by crystal violet
338.
Laboratory assistant has to isolate Clostridium tetani, anaerobic sporeforming bacterium, from
wound exudation. What will he do before inoculation of material into appropriate culture medium?
A. he filtrates the material through cellulose filter
B. *he heats the sample to kill asporogenous bacteria at 800C for 20 min
C. wound discharge should be frozen before inoculation to inhibit facultative anaerobes
D. he will not do anything before investigation
E. he heats the sample to kill vegetative forms bacteria at 600C for 5 min
339.
Special nutrient media on which it is possible to grow anaerobic microorganisms will be next:
A. *Zoessler, Kitt-Tarozzi's
B. Meat - peptone agar, meat - peptone broth
C. medium Endo's and Lewin's media
D. The curtailed serum, meat- peptone gelatin
E. Blood agar, serum agar
340.
Clostridium botulinum releases the most powerful biological poison which belongs to bacterial
exotoxins. Choose from proposed list target cell for botulotoxin:
A. Epithelial cell of the gut
B. Muscle cell
C. Motoneuron of central nervous system
D. Sensitive neuron of spinal cord
E. Inhibiting neuron of spinal cord
341.
The MOST important protective function of the antibody stimulated by tetanus toxoid is
A. To opsonize the Clostridium tetani
B. To prevent growth of the Clostridium tetani
C. To prevent adherence of the Clostridium tetani
D. *To neutralize the toxin of the Clostridium tetani
E. Inhibiting neuron of spinal cord
342.
Five days ago a 65-year-old woman with a lower urinary tract infection began taking ampicillin.
She now has a fever and severe diarrhea. Of the organisms listed, which one is MOST likely to be the
cause of the diarrhea?
A. *Clostridium difficile
B. Bacteroides fragilis
C. Proteus mirabilis
D. Bordetella pertussis
E. Clostridium tetani.
343.
Each of the following statements concerning Clostridium tetani is correct EXCEPT:
A. It is a gram-positive, spore-forming rod
B. Pathogenesis is due to the production of an exotoxin that blocks inhibitory neurotransmitters
C. *It is a facultative organism; it will grow on a blood agar plate in the presence of room air
D. Its natural habitat is primarily the soil
E. anaerobic sporeforming bacterium
344.
Spores are necessary to bacteria for:
A. Survival into human and animal’s organism
B. Reproduction
C. *Survival in an external environment
D. Defence from fagocytosis
E. Defence from acid in stomack
345.
Choose the nutrients media on which it is possible to grow anaerobic microorganisms:
A. Endo's and Lewin's media
B. Meat - pepton agar, meat - pepton broth
C. *Sugar - blood agar Zoessler, Kitt-Tarozzi's medium
D. The curtailed serum, meat-pepton gelatin
E. Blood agar, serum agar
346.
It is possible to cultivate obligate anaerobes on the special medium under absence of air. The
most reliable method to create anaerobic condition will be next:
A. usage of thermostat
B. *usage of anaerostat
C. by inoculation into solid media (pour agar culture)
D. usage of chemostat
E. by inoculation into simple media
347.
Each of the following statements concerning Clostridium perfringens is correct EXCEPT:
A. It causes gas gangrene
B. It causes food poisoning
C. It produces an exotoxin that degrades lecithin and causes necrosis and hemolysis
D. *It is a gram-negative rod that does not ferment lactose
E. anaerobic sporeforming bacterium
348.
Choose method of staining of bacterial spores, which are formed by C. perfringens:
A. Staining by mеthylene blue
B. *Staining by Aujesko’s method
C. Staining by Ziehl-Neelsen’s method
D. Staining by Gram method
E. Staining by crystal violet
349.
The drug of choice for antibiotic-associated pseudomembranous colitis is
A. penicillin G
B. *vancomycin
C. metronidazole
D. erythromycin
E. a combination of a beta-lactam and an aminoglycoside
350.
What microorganisms do not use oxygen and can actually be harmed by it?
A. *Obligate anaerobes
B. Facultative anaerobes
C. Obligate aerobes
D. Free radicals
E. microaerophiles
351.
Successful immunization against Tetanus results in production of antibodies that prevent disease.
By what mechanism do these protective antibodies prevent Tetanus?
A. Prevent binding of C. tetani endotoxin to monocyte receptors.
B. Bind C. tetani flagella, prevent cell motility and access to neurons.
C. Bind C. tetani cells and activate complement.
D. Bind toxin receptors on neuron plasma membranes, prevent binding/entry of toxin.
E. *Neutralize the protein exotoxin of C. tetani.
352.
A 55-year-old woman develops diplopia, one day after eating home-canned fruit. (Diplopia *
double vision, from inability to coordinate the direction of gaze of the eyes.) A few hours later she
develops difficulty speaking, bilateral weakness of her arms, nausea, vomiting, dizziness, blurred vision,
and dry mouth. However she is alert, oriented, and has no fever. If this is botulism, by what mechanism
did Clostridium botulinum produce her signs and symptoms?
A. Bound to Toll-like receptors and stimulated production of inflammatory cytokines.
B. Injected proteins into neurons via a type III secretion system.
C. *Secreted a protein toxin that enters mammalian neurons and blocks synaptic transmission.
D. Released peptidoglycan and other inflammatory components of the cell envelope.
E. Bacteremic spread followed by infection of multiple tissues: eyes, muscle, stomach, nervous
system, salivary glands.
353.
Home-canned food is a common source of botulism in adults. What property of C. botulinum
facilitates infection by this route?
A. *Produces airborne spores not easily killed by boiling.
B. Vegetative cells grow best at cooking temperatures.
C. Extremely resistant to gastric acid.
D. Thick peptidoglycan renders cells resistant to heat, cold, and drying.
E. Surface proteins inhibit digestive hydrolases.
354.
A patient has an abscess from which Bacterioides fragilis is isolated. Which condition is most
likely to have facilitated infection by this organism?
A. Treatment with trimethoprim/sulfa.
B. *Tissue ischemia.
C. Presence of neutrophils.
D. Antibiotic treatment for another bacterial infection.
E. Colonization of the large intestine with spores of this organism.
355.
A 61-year-old diabetic man is admitted to the hospital for severe pain in his right leg; the
diagnosis is obstruction of the femoral artery. The affected area of the leg is painful, red, and swollen.
During the next 12 hours the swelling increases markedly, the skin of the leg becomes discolored, and
fluid-filled blisters appear on the skin. Gram stain of fluid aspirated from a blister reveals large Grampositive rods. Which organism below is most likely to have caused this infection?
A. Clostridium botulinum.
B. Clostridium difficile.
C. *Clostridium perfringens.
D. Clostridium tetani.
E. Listeria monocytogenes.
356.
Medical important sporeforming bacteria belong to next genus:
A. Proteus
B. *Clostridia
C. Fusobacterium
D. Streptococcus
E. Escherihia
357.
Each of the following statements concerning Clostridia is correct EXCEPT:
A. Pathogenic Clostridia are found both in the soil and in the normal flora of the colon
B. Antibiotic-associated (pseudomembranous) colitis is due to a toxin produced by Clostridium
difficile
C. *Anaerobic conditions at the wound site are not required to cause tetanus, because spores will
form in the presence of oxygen
D. Botulism, which is caused by ingesting preformed toxin, can be prevented by boiling food prior
to eating
E. are Gram positive
358.
Clostridium botulinum releases the most powerful biological poison which belongs to bacterial
exotoxins. Choose from proposed list target cell for botulotoxin:
A. Epithelial cell of the gut
B. Muscle cell
C. *Motoneuron of central nervous system
D. Sensitive neuron of spinal cord
E. Inhibiting neuron of spinal cord
359.
To isolate pure culture of an obligate anaerobe from collected material you should choose the
most corresponding medium from the list:
A. Serum agar
B.
C.
D.
E.
Yolk agar
MPA
*Robertson’s cooked meat broth or Kitt-Tarozzi medium
MPB with glucose
360.
Surgeon has suspected anaerobic wound infection. To isolate causative germs collected wound
discharge should be cultivated into the such medium as :
A. Ploskirev agar
B. *Kitt-Tarozzi medium
C. meat peptone broth
D. Endo agar
E. meat peptone agar
361.
Laboratory assistant has to isolate Clostridia tetani, anaerobic sporeforming bacterium, from
wound exudation. What will he do before inoculation of material into appropriate culture medium?
A. he filtrates the material through cellulose filter
B. *he heats the sample to kill asporogenous bacteria at 800C for 20 min
C. wound discharge should be frozen before inoculation to inhibit facultative anaerobes
D. he will not do anything before investigation
E. he heats the sample to kill vegetative forms bacteria at 600C for 5 min
362.
Choose among these bacteria obligate anaerobes.
A. Neisseria gonorrhoeae, Streptococcus pneumoniae
B. Mycobacterium tuberculosis, Micrococcacae
C. *Clostridium perfringens Clostridium defficile
D. Bacillus anthracis, Brucella melitensis
E. Shigella dysenteriae, Salmonella typhi
363.
Five days ago a 65-year-old woman with a lower urinary tract infection began taking ampicillin.
She now has a fever and severe diarrhea. Of the organisms listed, which one is MOST likely to be the
cause of the diarrhea?
A. *Clostridium difficile
B. Bacteroides fragilis
C. Proteus mirabilis
D. Bordetella pertussis
364.
Each of the following statements concerning Clostridium perfringens is correct EXCEPT:
A. It causes gas gangrene
B. It causes food poisoning
C. It produces an exotoxin that degrades lecithin and causes necrosis and hemolysis
D. *It is a gram-negative rod that does not ferment lactose
E. are Gram positive
365.
Closcridium and Bacillus are unique among most bacteria in that they
A. are acid-fast
B. are Gram positive
C. *produce Endopores
D. do not have teichoic acids
E. are mesophiles
366.
A young man develops peritonitis following abdominal trauma. During surgery foul-smelling
purulent material is aspirated from the infected area. Gram stain of this material contains a mixture of
Grampositive cocci, Gram-positive rods, and many Gram-negative rods. Aerobic culture on sheep blood
agar yields many colonies of enterococci and a few colonies of E. coli; culture on MacConkey agar
produces only sparse colonies of E. coli. Anaerobic culture on sheep blood agar produces a few colonies
of beta-hemolytic Gram-positive rods and many colonies of slender Gram-negative rods. Which
organism is most likely to represent the majority of the Gram-negative rods seen when peritoneal
exudate was stained?
A. Yersinia enterocolitica
B. Clostridium perfringens
C. Clostridium tetani
D. Yersinia pseudotuberculosis
E. *Bacteroides fragilis
367.
A diabetic 78-year-old man develops a necrotic ulcer on his right foot. Infection spreads rapidly
and there is gas in soft tissues. His foot is amputated at the ankle. Gram stain of exudate from the
amputation site contains large Gram-positive rods. The bacteria grow well anaerobically, producing
large ?-hemolytic colonies on sheep blood agar, but do not grow aerobically. What organism is most
probable in this setting?
A. Bacillus cereus
B. Corynebacterium diphtheriae
C. Nocardia asteroides
D. Clostridium tetani
E. *Clostridium perfringens
368.
The spastic paralysis of Tetanus is the effect of a protein exotoxin. Which phrase below best
describes the process directly inhibited by Tetanus toxin?
A. Synthesis of neurotransmitter.
B. Transport of neurotransmitter into vesicles.
C. Calcium influx required for neurotransmitter release.
D. *Docking and fusion of neurotransmitter vesicles with the synaptic membrane.
E. Binding of neurotransmitter molecules to their receptors.
369.
A 50-year-old woman was treated for cystitis [caused by E. coli] with an oral broad-spectrum
antibiotic. Three weeks later she developed abdominal pain and diarrhea. A stained smear of stool
contained many neutrophils. Cultures for bacterial pathogens were negative. A serological test of stool
for Clostridium difficile toxin was positive. Which of the following is most likely to have been the
immediately predisposing cause of this patient’s C. difficile infection?
A. Colonization of her large intestine by antibiotic-resistant E. coli.
B. *Alteration of her intestinal flora by antibiotic treatment.
C. An allergic response to her antibiotic treatment.
D. Acquisition of an antibiotic-resistance plasmid (R-Factor) by C. difficile.
E. Binding of neurotransmitter molecules to their receptors
370.
A cyanotic, listless, infant with extremely poor muscle tone is brought to the Emergency Room.
Which condition is most likely, given this presentation?
A. *Botulism
B. Tetanus
C. Lyme Disease
D. Rocky Mountain spotted fever
E. Rheumatic fever
371.
Anaerobic bacteria may be propagated into the special media. Choose from following main
requirements to such media:
A. they should have low rH and be free from oxygen
B. t*hey should have high rH and be free from oxygen
C. they should contain minimal nutrients and be free from oxygen
D. they may have any rH and nutrients
E. All are true
372.
Each of the following statements concerning wound infections caused by Clostridium
perfringens is correct EXCEPT:
A. An exotoxin plays a role in pathogenesis
B. Gram-positive rods are found in the exudate
C. *The organism grows only in human cell culture
D. Anaerobic culture of the wound site should be ordered
E. All are true
373.
A security guard at a New Jersey Court House comes to your office with a large lesion on his left
arm. It is 10 cm in diameter and ulcerated. Surrounding tissue is red and markedly swollen. The ulcer is
healing to produce a black scab. A swab of the ulcer contains large Gram-positive rods. After aerobic
culture on sheep blood agar these produce large alpha-hemolytic colonies. Which organism is most
likely?
A. *Bacillus anthracis
B. Bacillus cereus
C. Clostridium difficile
D. Clostridium perfingens
E. Clostridium tetani
374.
An infant is brought to the emergency room, cyanotic and with poor muscle tone. Which
condition is most likely given these findings?
A. Antibiotic-associated colitis.
B. Diphtheria.
C. Anthrax.
D. *Botulism.
E. Tetanus.
375.
In the United States human Tetanus is now a rare disease. Which measure below has been most
important in preventing it?
A. Vaccination of livestock, especially cattle, with a killed-organism vaccine.
B. *Immunization of humans with a toxoid-containing vaccine.
C. Eradication of the organism from the environment.
D. Sewage treatment and purification of water supplies.
E. Antibiotic treatment of contacts of patients with C. tetani infections.
376.
Clostridium tetani produces disease by the production of a protein exotoxin. How does this toxin
act?
A. Stimulates adenyl cyclase.
B. Inhibits guanyl cyclase.
C. *Blocks synaptic transmission.
D. Cleaves ribosomal RNA.
E. Stimulates production of cytokines.
377.
Bipolar staining is characteristic of:
A. *Yersinia peslis.
B. Proteus mirabilis.
C. Pseudomonas aeruginosa.
D. Vibrio cholerae
E. all are true.
378.
Pneumonic plague can be transmitted from man to man by:
A. *droplet infection.
B. inoculation.
C. ingestion.
D. flea bite
E. all are true routes.
379.
Common reservoir host/s of Brucella melitensis is/are:
A. *sheep and goats.
B. cattle.
C. pigs.
D. dogs
E. all are true.
380.
Plague is transmitted by:
A. A.sandflies.
B. *rat fleas.
C. mites.
D. ticks.
E. louse
381.
Bubonic plague can be diagnosed in the laboratory by:
A. demonstration of gram-negative coccobacilli.
B. culture on blood agar.
C. inoculation in guinea-pigs.
D. inoculation in rats
E. *all are true.
382.
Which of the following Brucella spp. is most pathogenic for man?
A. B. abortus
B. *.B. melitensis.
C. B. suis.
D. B. canis.
E. B. ovis
383.
Bubonic plague is transmitted by:
A. *rat flea.
B. inhalation.
C. ingestion.
D. ticks
E. all are true routes.
384.
The name 'black death' is given to which of the following diseases?
A. Tuberculosis.
B. Diphtheria.
C. *Plague.
D. AIDS.
E. Cholera
385.
Brucellae are transmitted to humans by:
A. direct contact with animal tissues.
B. ingestion of contaminated meat.
C. ingestion of raw infected milk.
D. direct contact with animal placenta
E. *all are true.
386.
Human brucellosis is also known as
A. Fran's disease
B. Malta fever
C. rabbit fever
D. relapsing fever
E. *undulant fever
387.
Francisella tularensis has which portal of entry?
A. horse-fly
B. contact
C. intestinal
D. respiratory
E. *All are correct
388.
The bubo of bubonic plague is a/an
A. *enlarged lymph node
B. granuloma in the skin
C. infected sebaceous gland
D. tumor of lymph node
E. ulcer where the flea bite occurred
389.
Water to be used for parenteral injection must sterilized to kill living microbes and then further
purified to remove non-living bacterial components. Of those listed below, which is the most toxic?
A. *Lipopolysaccharide.
B. Polysaccharides of capsules.
C. Plasma-membrane lipids.
D. Proteins of the outer membrane.
E. Nucleic acids
390.
If you suspect Francisella infection, you should inform the lab when sending a specimen. What is
the predominant reason you need to do this?
A. Francisella requires culture in living human cells.
B. Francisella requires culture in living protozoa, such as amoebae.
C. Francisella although biologically Gram-negative, stains Gram-positive unless special technique
is used.
D. *Francisella is readily transmitted to laboratory workers when cultured.
E. Francisella cannot be cultured on ‘standard media’.
391.
In a patient with systemic febrile illness, which item in the history would indicate the highest risk
for Brucella infection?
A. *Contact with livestock or animal products.
B. Recent travel to China.
C. Chronic cardiopulmonary disease.
D. Age less than two years.
E. Drinking unpurified water from a river or stream.
392.
Brucella abortussis, a cause of undulant fever, is transmitted in all but which of the following
ways?
A. Direct contact with infected animals
B. Exposure to animal carcass
C. *Exposure to animal feces
D. Drinking unpasteurized milk
E. No correct answer
393.
Yersinia pestis causes both the Bubonic Plague and the more deadly Pneumonic Plague. How is
Pneumonic Plague transmitted?
A. The bite of a flea
B. Via rodents
C. *Air-borne
D. Exchange of bodily fluids
E. No correct answer
394.
Which one of the following zoonotic illnesses has NO arthropod vector?
A. Plague
B. Lyme disease
C. *Brucellosis
D. Epidemic typhus
E. All are true
395.
Each of the following statements concerning plague is correct EXCEPT:
A. Plague is caused by a gram-negative rod that can be cultured on blood agar
B. Plague is transmitted to humans by flea bite
C. The main reservoirs in nature are small rodents
D. *Plague is of concern in many underdeveloped countries but has not occurred in the United
States since 1968
E. All are true
396.
Escherichia, Salmonella, Yersinia, and Shigella are put together in Bergey's Manual because they
are all
A. pathogens
B. *gram-negative facultatively anaerobic rods
C. gram-positive aerobic cocci
D. fermentative
E. all are false
397.
A 13-year old boy develops pain and marked (10 cm.) swelling in his right inguinal lymph node
accompanied by fever of 104oF. He and his family have just returned from a vacation trip to Arizona
and New Mexico. Aspirate from the node contains Gram-negative rods. A direct immunofluorescent
assay on the aspirate provides a definitive diagnosis. The child is (successfully) treated with
streptomycin, and the aspirate is sent for culture to the CDC. Culture yields pale colonies on
MacConkey agar. What is the most probable pathogen?
A. *Yersinia pestis.
B. Helicobacteri pylori.
C. Franciscella tularensis.
D. Coxiella burnetii.
E. Klebsiella pneumoniae
398.
The following are characterized by bradycardia except
A. Typhoid fever
B. *Brucellosis
C. Leptospirosis
D. Yellow fever
E. No correct answer
399.
A 34-year old person has rapidly developing cough, dyspnoea, expectoration ana blood-tinged
sputum, he is febrile, cyanosed and toxic. Chest examination reveals crepitations and rhonchi. The most
likely diagnosis is
A. Legionella pneumonia
B.
C.
D.
E.
*Pneumonic plague
Septicaemic plague
Pulmory tuberculosis
No correct answer
400.
Milk ring test
A. *Brucellosis
B. Bacteroides
C. Tuberculosis
D. Salmonellosis
E. Diphtheria
401.
Bubo is seen in
A. typhoid fever
B. *Plague
C. Lymphoma
D. Filariasis
E. Scarlet fever
402.
Which is not a zoonotic disease
A. Rabies
B. Anthrax
C. Plague
D. Brucellosis
E. *All are correct
403.
Undulant fever is caused by
A. Bartonella
B. *Brucella melitensis
C. Bordetella
D. Borrelia recurrentis
E. Streptococci
404.
Granuloma with stellate abscess
A. TB
B. *Tularemia
C. Sarcoidosis
D. Staphylococcus
E. Streptococcus
405.
Organism most likely to cause "fevert of unknown origin" in a farmer who raises goats
A. *Brucella melitensis
B. Clostridium novyi
C. Histoplasma capsulatum
D. Mycobacterium tuberculosi
E. No correct answer
406.
Which of the following describes enteric bacteria?
A. Gram-positive cocci
B. Gram-negative cocci
C. Gram-positive rods
D. *Gram-negative rods
E. Gram-positive spirals
407.
Bubonic plagues (Y. pestis) is characterized by and pneumonic plague (Y. pestis) is
characterized by
A. *A 7-day incubation period; A 3-day incubation period
B. A > 90% mortality rate; A >75% mortality rate
C. Pulmonary disease; A painful bubo (inflammation of the lymph nodes)
D. Aerosol spreading from person-to-person; Flea bites
E. Septicemia; Cutaneous hemorrhagic necrosis
408.
Which of the following is the natural reservoir for urban plague (Y. pestis)?
A. Cows
B. Rabbits
C. Turtles
D. *Rats
E. Mosquitoes
409.
Which of the following is NOT a natural reservoir for sylvatic plague (Y. pestis)?
A. Squirrels
B. Rabbits
C. *Livestock
D. Rats
E. Domestic cats
410.
Brucella and Francisella are examples of what kind of disease, where they can be transmitted
from animal to human?
A. Nosocomial
B. Water-borne
C. Blood-borne
D. *Zoonosis
E. Opportunistic
411.
What is the primary virulence factor of the intracellular parasite F. tularensis?
A. cAMP inducing toxin
B. *Capsule
C. Spore
D. Teichoic acid
E. Type III secretion system
412.
Which of the following carriers of F. tularensis is the most common for transmission to a human
host?
A. Domestic cats
B. Birds
C. Ticks
D. Domestic cats and dogs
E. *Rabbits and ticks
413.
Which of the following locations is the least likely for F. tularensis (tularemia) to be found?
A. Arkansas
B. Oklahoma
C. Missouri
D. Pennsylvania
E. *Australia
414.
What growth factors are required for F. tularensis?
A. Heme (X)
B. NAD (V)
C. Heme and NAD (X and V)
D. *Cysteine
E. Cysteine and heme (X)
415.
A doctor is struggling to diagnose a woman’s flulike illness. She complains of a fever that rises
during the day and peaks after dinner (undulant fever), fatigue, spinal tenderness, and loss of appetite.
Her lymph nodes are enlarged in physical exam. The doctor has trouble narrowing down the possible
etiologies until he hears that the tasted goat cheese at a French village a month before the onset of her
symptoms. Which of the following is the most likely cause?
A. Streptococcus pneumoniae
B. *Pseudomonas aeruginosa
C. Bordetella pertussis
D. Francisella tularensis
E. Brucella species
416.
Which of the following is NOT true (in general) for Clostridium?
A. *Gram-negative
B. Bacilli shaped
C. Spore-forming
D. Obligate anaerobes
E. Unable to reduce sulfate to sulfite
417.
A teenage girl enters the emergency room suffering painful muscle spasms. Throughout her
examination, she sustains a facial sneer, a stiff arched back, and clamped palms. Her father is anxious
about the fact that she has also experienced difficulty eating, probably due to a stiff jaw. The father
affirms that her daughter is usually quite active and boasts how, a week ago, she continued a soccer
game even after falling on a nail in the field. Which of the following is the most likely cause?
A. C. difficile
B. C. perfingens
C. C. septicum
D. C. botulinum
E. *C. tetani
418.
A woman straggles into the emergency room with a marked paralysis of her upper body. She
describes the paralysis as a weakness that began in her neck and spread to her arms. She also complains
of blurred double vision and requests water to soothe her dry throat. Though she has no fever, she
appears quite dizzy and her eyelids are drooping. The day before, she returned from a camping trip
where she insists she maintained good hygiene, limiting her diet to canned food only. Which of the
following is the most likely cause?
A. C. difficile
B. C. perfingens
C. C. septicum
D. *C. botulinum
E. C. tetani
419.
An old woman comes to the doctor with a fever and loose bowels. Her diarrhea occurs in
tremendous volumes, she complains, though she doesn’t remember seeing blood. She has an
unremarkable recent past medical history, except for an infection a few weeks earlier that was treated
with clindamycin. Sigmoidoscopy of her colon reveals yellow-white plaques which the doctor predicted
after analyzing her stools for toxins. Which of the following is the most likely cause?
A. *C. difficile
B. C. perfingens
C. C. septicum
D. C. botulinum
E. C. tetani
420.
A man enters the emergency room claiming to have been stabbed two days earlier. Muscles in
his arm hurt, and on palpation small air bubbles are felt below the skin. The wound area exudes a
blackish, ill-smelling fluid that generates a crackling sound when touched. The patient has a fever, a low
blood pressure, marked tachycardia, and urina very little since his injury. The doctor decides to
amputate the arm, as well as monitor the patient for shock and renal failure Which of the following is
the most likely cause?
A. C. difficile
B. *C. perfingens
C. C. septicum
D. C. botulinum
E. C. tetani
421.
Which of the following is a cause of nontraumatic myonecrosis and often exists in patients with
occult colon cancer, acute leukemia, or diabetes?
A. C. difficile
B. C. perfingens
C. *C. septicum
D. C. botulinum
E. C. tetani
422.
Which of the following is associated with Floppy Baby Syndrome?
A. C. difficile
B. C. perfingens
C. C. septicum
D. *C. botulinum
E. C. tetani
423.
Which of the following is associated with Pseudomembrane Colitis (PMC)?
A. *C. difficile
B.
C.
D.
E.
C. perfingens
C. septicum
C. botulinum
C. tetani
424.
Which of the following describes the effect of tetanus toxin?
A. *Unregulated excitatory synaptic activity in the motor neurons
B. Blocks neurotransmission at peripheral cholinergic synapses
C. Induces depolymerization of actin with loss of cellular cytoskeleton
D. Produces chemotaxis; induces cytokine production with hypersecretion of fluid; produces
hemorrhagic necrosis
E. All are correct
425.
Which of the following describes the effect of botulinum toxin?
A. Unregulated excitatory synaptic activity in the motor neurons
B. *Blocks neurotransmission at peripheral cholinergic synapses
C. Induces depolymerization of actin with loss of cellular cytoskeleton
D. Produces chemotaxis; induces cytokine production with hypersecretion of fluid; produces
hemorrhagic necrosis
E. All are correct
426.
Which of the following describes the effect of C. difficile toxin?
A. Unregulated excitatory synaptic activity in the motor neurons
B. Blocks neurotransmission at peripheral cholinergic synapses
C. Induces depolymerization of actin with loss of cellular cytoskeleton
D. Produces chemotaxis; induces cytokine production with hypersecretion of fluid; produces
hemorrhagic necrosis
E. *All are correct
427.
A mother brings her 12-year-old son to your office because he has a skin lesion on his back. It is
20 cm in diameter, with a red inflamed border and a red center, with a paler ring between the red areas.
The mother says it has expanded rapidly over the last few days. Which of the following would be most
likely to cause such a lesion?
A. Rickettsia rickettsii
B. Treponema pallidum
C. *Borrelia burgdorferi
D. Chlamydia psittaci
E. Streptococcus pyogenes
428.
A 16-year-old boy has a skin lesion on his back. It is 20 cm in diameter, with a red inflamed
border and a red center, with a paler ring between the red areas. He says it has expanded rapidly over the
last few days after tick bite. Which of the following would be most likely to cause such a lesion?
A. Rickettsia rickettsii
B. *Borrelia burgdorferi
C. Treponema pallidum
D. Chlamydia psittaci
E. Streptococcus pyogenes
429.
What vectors are spread an epidemic typhus?
A. Rat fleas.
B. Dog ticks.
C. *Human body lice.
D. Mosquitos.
E. Deer ticks.
430.
A patient is diagnosed with pelvic inflammatory disease (PID), you suspect caused by
Chlamydia trachomatis. If you wished to confirm C. trachomatis, which test below should you use?
A. Culture of urine on broth-based agar at 20?C.
B. Culture of cervical exudate on chocolate agar in elevated CO2.
C. Microscopic examination of a stained smear of peripheral blood.
D. *Gram stain of exudate from the cervix.
E. PCR-based nucleic-acid amplification test of a cervical swab.
431.
Which of the following staining techniques cannot be used for T. pallidum?
A. *Gram staining.
B.
C.
D.
E.
Giemsa staining.
Silver impregnation staining.
Imunofluorescence staining.
Burri staining.
432.
Louse-borne relapsing fever is caused by:
A. *Borrelia recurrentis.
B. B. duttoni.
C. B. burgdorferi.
D. B. parkeri.
E. B. persica
433.
Which of the following bacteria dies quickly after drying?
A. Mycobacterium tuberculosis.
B. Staphylococcus aureus.
C. Pseudomonas aeruginosa.
D. Bacillus anthracis
E. *Treponema pallidium
434.
In which of the following sexually transmitted diseases, ulcer/s is/are painless?
A. *Syphilis.
B. Chancroid.
C. Herpes genitalis.
D. All are true.
E. No correct answer
435.
Treponema pallidum can be cultivated in:
A. *rabbit testes.
B. blood agar medium.
C. chocolate agar medium.
D. Thayer-Martin medium.
E. Kitt-Tarozi medium
436.
Relapses in relapsing fever occur due to:
A. *antigen variation in bacteria.
B. increased toxin production by bacteria.
C. increased invasiveness of bacteria.
D. super infection with viruses.
E. increased fermentative activity of bacteria
437.
Human body louse is responsible for transmission of which of the following diseases?
A. *Epidemic typhus.
B. Murine typhus.
C. C.Rickettsialpox.
D. Q fever.
E. Typhi fever
438.
Sterols are present in the cytoplasmic membrane of:
A. *Mycoplasma.
B. Bacillus.
C. Clostridium.
D. Proteus.
E. Rickettsia
439.
Which of the following bacteria is/are implicated as causative agent/s of non-gonococcal
urethritis?
A. Chlamydia trachomatis.
B. Ureaplasmau urealyticum.
C. Mycoplasma hominis.
D. Herpes virus 2
E. *All are true
440.
Appearance of a hard chancre is characteristic of:
A. *primary syphilis.
B. secondary syphilis.
C. latent syphilis.
441.
442.
443.
444.
445.
446.
447.
448.
449.
450.
D. tertiary syphilis.
E. complication of syphilis
Lyme disease is caused by:
A. Borrelia recurrenlis.
B. B. dutioni.
C. *B. burgdorferi.
D. B. hermsii
E. B. persica
Treponema pallidum is cultured in/on
A. blood agar
B. eggs
C. horse serum
D. *rabit testis
E. serum broth
Formation of a gumma is
A. a damaged aorta
B. a damaged liver
C. *a syphilitic tumor
D. the primary lesion of syphilis
E. the result of congenital syphilis
The treatment of choice for syphilis is:
A. antiserum
B. aurum drug
C. penicillin
D. *sulfa drugs
E. tetracycline
All the treponematoses are not veneral disease except:
A. bejel
B. pinta
C. yaws
D. *syphilis
E. All are true
Lyme disease is caused by ______ and spread by ______.
A. Borrelia recurrentis, lice
B. *Borrelia burgdorferi, ticks
C. Borrelia burgdorferi, chiggers
D. Borrelia hermsii, ticks
E. Borrelia recurrentis, ticks
Epidemic Relapsing fever is spread by
A. *lice
B. ticks
C. flea
D. mosquites
E. animal urine
Endemic Relapsing fever is spread by
A. lice
B. *ticks
C. flea
D. mosquites
E. animal urine
Rickettsias and chlamydias are similar in being
A. carried by arthropod vectors
B. free of a cell wall
C. *obligate intracellular bacteria
D. produce exotoxin
E. the cause of eye infections
Which of the following is/are an arthropod vector of rickettsioses?
A.
B.
C.
D.
E.
flea
louse
tick
*all are true
no correct answer
451.
Chlamydia trachomatis can attacks which structure(s)?
A. eye
B. urethra
C. fallopian tubes
D. lungs
E. *all of these
452.
Ornithosis is a _____ infection associated with ______
A. rickettsial, parrots
B. chlamydial, mice
C. *chlamydial, birds
D. rickettsial, flies
E. chlamydial, rats
453.
Mycoplasmas demage next structure of host cells.
A. nucleus
B. cell walls
C. ribosomes
D. *cell membranes
E. mitochondria
454.
You suspect Chlamydia infection in a sexually-active young woman. Which test would be most
likely to provide results which would confirm this diagnosis?
A. Agglutination test for anti-cardiolipin antibodies.
B. *PCR test of nucleic acids present in a urine sample.
C. Test of a blood sample for ‘cold agglutinins”.
D. Gram-stained smear of discharge from the cervix.
E. Culture of exudate from the cervix on Thayer-Martin agar.
455.
A mother is worried that the child may have contracted Lyme disease. Which finding would
most strongly suggest that she is correct?
A. A disseminated rash, with small papular erythematous lesions.
B. An ulcer and edema at the site of the tick bite.
C. A lesion at the site of the tick bite that develops a thick, black, crusted, scab.
D. *A “bull’s-eye” lesion with erythematous periphery and central clearing.
E. A sparse red macular rash, on the palms and soles only.
456.
A 25-year-old female presented with a three-day history of fever, headache and a non-productive
cough. X-rays show bilateral diffuse lung infiltrates. Culture of a throat swab (on sheep blood and
chocolate agars) revealed only “normal oral flora”. Penicillin G was prescribed and the patient sent
home. Her illness did not respond to this antibiotic. She was then successfully treated with
erythromycin. Which organism is most likely to have caused her illness?
A. *Mycoplasma pneumoniae.
B. Haemophilus influenzae.
C. Mycobacterium tuberculosis.
D. Streptococcus pyogenes.
E. Streptococcus pneumoniae.
457.
A patient has a positive Rapid Plasma Reagin (RPR) test for ‘non-treponemal antibodies’. A test
for specific anti-treponemal antibodies is positive but the patient has no rash, genital lesions,
inflammation, or discharge. Which conclusion best follows from these findings?
A. The patient does not require antibiotic treatment; absence of symptoms indicates that the positive
RPR is a ‘biological false positive”.
B. The patient has Syphilis, but does not require antibiotic treatment, because infections with
Treponema pallidum normally resolve spontaneously.
C. The patient has Syphilis, but the diagnosis should be confirmed by culture before
antibiotictreatment is started.
D. *The patient has Syphilis, and should be treated with Penicillin G
E. No correct answer
458.
Chlamydia trachomatis may be cultured on monolayers of human cells. If infected cells were
examined by staining and light microscopy, what would you be most likely to observe?
A. *A membrane-bounded inclusion body, within the nucleus.
B. A membrane-bounded inclusion body, within the cytoplasm.
C. Rod shaped Gram-positive bacilli, free within the cytoplasm.
D. Gram-negative cocci, within the lumen of the endoplasmic reticulum.
E. Cyst forms inside lysosomes.
459.
In August, a young man presents with a history of fever for 1 week and a red rash which extends
to the palms and soles. IgM titer to Rickettsia rickettsii is 1:640. From which vector was this infection
most likely to have been acquired?
A. *Dog tick.
B. Mosquito of the genus Anopheles.
C. Blood-sucking sandfly.
D. Flea.
E. Human body louse.
460.
The cell tropism of the genus Rickettsia determines the type of disease produced. Which phrase
best describes Rickettsial disease?
A. Encephalitis
B. Meningitis.
C. Myocarditis.
D. Myositis.
E. *Vasculitis.
461.
The symptom of secondary syphilis is
A. neurological problems
B. giant lesions affecting many internal organs
C. a hard-based, painless chancre
D. *a rash covering all parts of the body
E. All are true
462.
Syphilis is caused by which of the following?
A. Helicobacter pylori
B. Proteus mirabilis
C. *Treponema pallidum
D. Serratia marcesans
E. Treponema Vincentii
463.
Borellia burgdorferi causes which disease?
A. *Lyme Disease
B. Rocky Mountain Spotted Fever
C. Hanta
D. Rabies
E. Relapsing fever
464.
How is leptospirosis, caused by Leptospira interrogans, transmitted?
A. Tick bite
B. *Contaminated urine in food or water
C. Undercooked meat
D. Inhaled aerosol
E. louse feces
465.
Rickettsia rickettsii causes Rocky Mountain Spotted fever when transmitted by tick bite. When
transmitted by lice, it causes:
A. *Epidemic typhus
B. Scarlet fever
C. Hydrocephalus
D. Rheumatic fever
E. No correct answer
466.
Which of the following is NOT true about Mycoplasma hominis?
A. Synonymous with Ureaplasma urealyticum
B. More prevalent in late summer/early fall
C. *Vaccine uses conjugated polysaccharide B
D. Is endemic worldwide
E. No correct answer
467.
What is the first symptom of Treponema pallidum?
A. *Chancre at infection site
B. Bullseye rash
C. Butterfly rash
D. Vaginal discharge
E. No correct answer
468.
Which one of the following diseases is BEST diagnosed by serologic means?
A. *Q fever
B. Pulmonary tuberculosis
C. Gonorrhea
D. Actinomycosis
E. All are true
469.
Which one of the following organisms principally infects vascular endothelial cells?
A. Salmonella typhi
B. *Rickettsia typhi
C. Haemophilus influenzae
D. Coxiella burnetii
E. All are true
470.
Each of the following statements concerning chlamydiae is correct EXCEPT:
A. Chlamydiae are strict intracellular parasites because they cannot synthesize sufficient ATP
B. Chlamydiae possess both DNA and RNA and are bounded by a cell wall
C. trachomatis has multiple serotypes, but C psittaci has only one serotype
D. *Most chlamydiae are transmitted by arthropods
E. All are true
471.
A 25-year-old man complains of a urethral discharge. You perform a Gram stain on a specimen
of the discharge and see neutrophils but no bacteria. Of the organisms listed, the one MOST likely to
cause the discharge is
A. Treponema pallidum
B. *Chlamydia trachomatis
C. Candida albicans
D. Coxiella burnetii
E. All are true
472.
Each of the following statements concerning Treponema is correct EXCEPT:
A. *T. pallidum produces an exotoxin that stimulates adenylate cyclase
B. T. pallidum cannot be grown on conventional laboratory media
C. Treponemes are members of the normal flora of the human oropharynx
D. Patients infected with T. pallidum produce antibodies that react with beef heart cardiolipin
E. All are true
473.
Each of the following statements concerning chlamydial genital tract infections is correct
EXCEPT:
A. *Infection can be diagnosed by finding anti-chlamydial antibody in a serum specimen
B. Infection can persist after administration of penicillin
C. Symptomatic infections can be associated with urethral or cervical discharge containing many
polymorphonuclear leukocytes
D. There is no vaccine against these infections
E. All are true
474.
Each of the following statements concerning Chlamydia trachomatis is correct EXCEPT:
A. It is an important cause of nongonococcal urethritis
B. It is the cause of lymphogranuloma venereum
C. *It is an important cause of subacute bacterial endocarditis
D. It is an important cause of conjunctivitis
E. All are true
475.
Which one of the following types of organisms is NOT an obligate intracellular parasite and
therefore can replicate on bacteriologic media?
A.
B.
C.
D.
E.
Chlamydia
*Mycoplasma
Adenovirus
Rickettsia
All are true
476.
The soil is the natural habitat for certain microorganisms of medical importance. Which one of
the following is LEAST likely to reside there?
A. Clostridium tetani
B. Mycobacterium intracellular
C. Bacillus anthracis
D. *Chlamydia trachomatis
E. All are true
477.
Each of the following statements concerning the VDRL test for syphilis is correct EXCEPT:
A. *The antigen is composed of inactivated Treponema pallidum
B. The test is usually positive in secondary syphilis
C. False-positive results are more frequent than with the FTA-ABS test
D. The antibody titer declines with adequate therapy
E. All are true
478.
Each of the following statements concerning epidemic typhus is correct EXCEPT:
A. The disease is characterized by a rash
B. The Weil-Felix test can aid in diagnosis of the disease
C. The disease is caused by a rickettsia
D. *The causative organism is transmitted from rodents to humans by a tick
E. All are true
479.
Each of the following statements concerning spirochetes is correct EXCEPT:
A. Species of Treponema are part of the normal flora of the mouth
B. Species of Borrelia cause a tick-borne disease called relapsing fever
C. *The species of Leptospira that cause leptospirosis grow primarily in humans and are usually
transmitted by human-to-human contact
D. Species of Treponema cause syphilis and yaws
E. All are true
480.
Each of the following statements concerning infection with Chlamydia psittaci is correct
EXCEPT:
A. C psittaci can be isolated by growth in cell culture and will not grow in blood agar
B. The organism appears purple in Gram-stained smears of sputum
C. The infection is more readily diagnosed by serologic tests than by isolation of the organism
D. *The infection is more commonly acquired from a nonhuman source than from another human
E. All are true
481.
Ticks are vectors for the transmission of each of the following diseases EXCEPT:
A. Rocky Mountain spotted fever
B. *epidemic typhus
C. tularemia
D. Lyme disease
E. All are true
482.
Each of the following statements concerning pneumonia caused by Mycoplasma pneumoniae is
correct EXCEPT:
A. The disease is associated with a rise in the titer of cold agglutinins
B. *The disease occurs primarily in immunocompetent individuals
C. The disease is one of the "atypical" pneumonias
D. The organism cannot be cultured in vitro because it has no cell wall
E. All are true
483.
Each of the following statements concerning Q fever is correct EXCEPT:
A. *Rash is a prominent feature
B. It is transmitted by respiratory aerosol
C. Farm animals are an important reservoir
D. It is caused by Coxiella burnetii
E. All are true
484.
Lyme disease is caused by a
A. Chlamydiae
B. Rickettsiae
C. *a spirochete
D. enteric bacteria
E. all are false
485.
Borrelia is classified with the spirochetes because it
A. is aerobic
B. *possesses an axial filament
C. is a rod
D. is a pathogen
E. none of answers
486.
An 8-year-old boy living in a wooded area of Virginia suddenly developed fever, headache, and
myalgia. On physical exam, a rash was noted on his limbs and trunk. Lesions of the rash were red and a
few mm in diameter. No organisms were isolated from several blood cultures. The child was treated
with tetracycline and recovered. Serological tests of acute and convalescent serum samples from the
child are most likely to reveal an increase in antibody titer to...
A. Borrelia burgdorferi.
B. Chlamydia pneumoniae.
C. Franciscella tularensis.
D. Yersinia pestis.
E. *Rickettsia rickettsii.
487.
A 15-year-old female presented with a three-day history of fever, headache and a non-productive
cough. Penicillin was prescribed and the patient was sent home. Her illness did not respond to this
antibiotic. Gram stain and culture of the patient's sputum and a throat swab revealed only 'normal oral
flora'. She was then successfully treated with erythromycin. Which organism below is most likely to
have caused her illness?
A. *Mycoplasma pneumoniae.
B. Haemophilus influenzae
C. Mycobacterium tuberculosis.
D. Corynebacterium diphtheriae.
E. Streptococcus pneumoniae.
488.
Which of the following bacteria can be successfully cultured on cell-free medium?
A. Chlamydia trachomatis.
B. Coxiella burnetii.
C. Mycobacterium leprae.
D. *Mycoplasma pneumoniae.
E. Rickettsia prowazekii.
489.
Indicate disease caused by Treponema pallidum:
A. Weil syndrome (icterohemorrhagic fever), canicola fever
B. Endemic relapsing fever
C. Lyme disease
D. *Syphilis
E. Enteric fever
490.
Indicate disease caused by Leptospira interrogans:
A. *Weil syndrome (icterohemorrhagic fever), canicola fever
B. Endemic relapsing fever
C. Lyme disease
D. Syphilis
E. Enteric fever
491.
Indicate disease caused by Borrelia burgdorferi:
A. Weil syndrome (icterohemorrhagic fever), canicola fever
B. Endemic relapsing fever
C. *Lyme disease
D. Syphilis
E. Enteric fever
492.
Indicate disease caused by Borrelia recurrentis:
A.
B.
C.
D.
E.
Weil syndrome (icterohemorrhagic fever), canicola fever
*Endemic relapsing fever
Lyme disease
Syphilis
Enteric fever
493.
Which of the following is true for visualizing spirochete?
A. They can be viewed without significant magnification (e.g. 10x)
B. They can be viewed with Gram stain
C. They can be viewed with Giemsa stain
D. *They require special analysis such as dark field illumination or silver stain
E. They are eucaryotes
494.
Which of the following groups of people is most at risk for contracting T. pallidum?
A. Pregnant mothers
B. Cystic fibrosis patients
C. *Sexually active patients
D. Elderly patients
E. Anyone (spread through contact with inanimate objects, such as toilet seats)
495.
The tissue destruction and lesions observed in syphilis are primarily a consequence of which of
the following?
A. Bacterial capsule
B. Bacterial endoflagellum
C. Bacterial overgrowth
D. Bacterial hyaluronidase
E. *Host immune response
496.
What stage of syphilis is characterized by disseminating rash, alopecia, lymphadenopathy, and
flulike symptoms.
A. Primary
B. *Secondary
C. Tertiary
D. Congenital
E. No correct answer
497.
Children born with congenital syphilis often exhibit Hutchinson Triad, which includes deafness,
blindness, and centrally notched teeth. If the mother has been exposed to Chlamydia, syphilis, or
gonorrhea, the newborn may receive a prophylactic antibiotic for their:
A. Ears
B. *Eyes
C. Nose
D. Mouth
E. Systemic antibiotic (via IV)
498.
What is characteristic of primary syphilis?
A. Painful chancre
B. *Painless chancre
C. Several painful ulcers in genital region
D. Several painless ulcers in genital region
E. Disseminating rash on entire body, soles, and palms
499.
Of the following organisms that can cross the placenta, which of the following is associated with
congenital CN VIII deafness, mulberry molars, saddle nose, blindness, deafness, and cardiovascular
problems?
A. Toxoplasma gondii
B. Rubella
C. Cytomegalovirus
D. Herpes, HIV
E. *Syphilis
500.
Which of the following is/are used to confirm nontreponemal assays?
A. Venereal Disease Research Laboratory (VDRL) test
B. Rapid Plasma Reagin (RPR) test
C. Agglutination test
D. *Treponema pallidum particle agglutination (TP-PA) test
E. All are true
501.
Indicate microbe which has sexual mode of transmission:
A. *Treponema pallidum
B. Borrelia recurrentis
C. Borrelia burgdorferi
D. Leptospiras interrogans
E. Treponema vincentii
502.
Indicate microbe which uses ticks for mode of transmission:
A. Treponema pallidum
B. Borrelia recurrentis
C. *Borrelia burgdorferi
D. Leptospiras interrogans
E. Treponema vincentii
503.
Indicate microbe which uses ticks for mode of transmission:
A. Treponema pallidum
B. Borrelia recurrentis
C. *Borrelia burgdorferi
D. Leptospiras interrogans
E. Treponema vincentii
504.
Indicate microbe which uses rodents, dogs, fish, birds for mode of transmission:
A. Treponema pallidum
B. Borrelia recurrentis
C. Borrelia burgdorferi
D. *Leptospiras interrogans
E. Treponema vincentii
505.
Indicate microbe which uses human-to-human for mode of transmission:
A. Treponema pallidum
B. *Borrelia recurrentis
C. Borrelia burgdorferi
D. Leptospiras interrogans
E. Treponema vincentii
506.
Which of the following is an early clinical sign of Lyme Disease and not a late sign?
A. Musculoskeletal disease (e.g. migratory myalgias, transient arthritis)
B. Nervous system disease (e.g. Bell palsy, encephalopathy)
C. Cardiovascular involvement (e.g. AV nodal block)
D. *Erythema chronicum migrans (ECM)
E. Acrodermatitis chronicum atrophicans (ACA)
507.
Which of the following locations within the United States has the highest reported cases of
Leptospira infection each year?
A. Minnesota
B. Pennsylvania
C. New York
D. Wisconsin
E. *Hawaii
508.
A farmer comes to the ER with a 1-week history of flu-like symptoms with photophobia. His
severe headache, cough, and myalgias suggest to the physician some kind of respiratory infection.
However, more careful physical exam reveals conjunctival suffusion and macular rash. Lab findings
include elevated serum bilirubin, alkaline phosphatase, aminotransferase, and creatine phosphokinase.
With this clinical picture and lab results, the physician prescribes penicillin G immediately. His
suspicions are confirmed later when a spirochete is isolated from the patient’s blood. Which of the
following is the most likely cause?
A. Treponema pallidum
B. *Leptospira interrogans
C. Borrelia burgdorferi
D. Borrelia recurrentis
E. Treponema vincentii
509.
Mycoplasma pneumoniae (Eaton agent) are unique among bacteria because their cell membrane
contains sterols and they do not have which of the following?
A. ?-lactam antibiotic resistance
B. Flagella
C. Endotoxin
D. Capsule
E. *Cell wall
510.
Which of the following is associated with Ureaplasma?
A. *Genitourinary tract infection
B. Atypical pneumonia
C. Tracheobronchitis
D. Influenza-like illness
E. Upper respiratory tract infection
511.
Mycoplasma pneumoniae is a common cause of atypical pneumonia (walking pneumonia) and
chest x-ray often looks worse than symptoms suggest. Which of the following groups of people is the
most commonly affected?
A. Elderly
B. Middle-aged adults
C. *School-age children
D. Neonates
E. Pregnant mothers
512.
Which of the following tests is the most useful currently as an initial laboratory test, has about
65% sensitivity, and has specificity that cross-reacts to other organisms (e.g., Epstein-Barr virus,
cytomegalovirus, adenovirus)?
A. Microscopy
B. Molecular diagnosis
C. Complement fixation
D. Enzyme immunoassays
E. *Cold hemagglutination
513.
Which of the following is an organism that prefers to live inside a host cell but may live outside
a host cell?
A. Extracellular pathogen
B. Intracellular pathogen
C. Obligate intracellular parasite
D. Obligate extracellular parasite
E. *Facultative intracellular parasite
514.
Rickettsia, an aerobic Gram-negative rod, is which of the following?
A. Extracellular pathogen
B. *Obligate intracellular parasite
C. Obligate extracellular parasite
D. Facultative intracellular parasite
E. No correct answer
515.
What disease does Rickettsia rickettsii cause?
A. *Rocky Mountain spotted fever (Western hemisphere)
B. Epidemic typhus (Worldwide)
C. Scrub typhus (Asia, Oceania)
D. Q fever (Worldwide)
E. Relapsing fever
516.
What disease does Rickettsia prowazekii cause?
A. Rocky Mountain spotted fever (Western hemisphere)
B. *Epidemic typhus (Worldwide)
C. Scrub typhus (Asia, Oceania)
D. Q fever (Worldwide)
E. Relapsing fever
517.
What disease does Orientia tsutsugamushi cause?
A. Rocky Mountain spotted fever (Western hemisphere)
B. Epidemic typhus (Worldwide)
518.
519.
520.
521.
522.
523.
524.
525.
526.
C. *Scrub typhus (Asia, Oceania)
D. Q fever (Worldwide)
E. Enteric fever
What disease does Coxiella burnetii cause?
A. Rocky Mountain spotted fever (Western hemisphere)
B. Epidemic typhus (Worldwide)
C. Scrub typhus (Asia, Oceania)
D. *Q fever (Worldwide)
E. Scarlet fever
Match the with Rickettsia: Rocky Mountain spotted fever (Western hemisphere)
A. Orientia tsutsugamushi
B. Coxiella burnetii
C. *Rickettsia rickettsii
D. Rickettsia prowazekii
E. No correct answer
Match the Epidemic typhus (Worldwide) with Rickettsia:
A. Orientia tsutsugamushi
B. Coxiella burnetii
C. Rickettsia rickettsii
D. *Rickettsia prowazekii
E. No correct answer
Match the Scrub typhus (Asia, Oceania) with Rickettsia:
A. *Orientia tsutsugamushi
B. Coxiella burnetii
C. Rickettsia rickettsii
D. Rickettsia prowazekii
E. No correct answer
Match the Q fever (Worldwide) with Rickettsia:
A. Orientia tsutsugamushi
B. Coxiella burnetii
C. Rickettsia rickettsii
D. Rickettsia prowazekii
E. *No correct answer
Match the following vector – cattle, sheep, goats – with Rickettsia
A. Orientia tsutsugamushi
B. Coxiella burnetii
C. Rickettsia rickettsii
D. Rickettsia prowazekii
E. Bartonella quintana
Match the following vector – flying squirrels, louse – with Rickettsia
A. Orientia tsutsugamushi
B. Coxiella burnetii
C. Rickettsia rickettsii
D. *Rickettsia prowazekii
E. Bartonella quintana
Match the following vector – dogs, rodents, wood/dog tick – with Rickettsia
A. Orientia tsutsugamushi
B. Coxiella burnetii
C. *Rickettsia rickettsii
D. Rickettsia prowazekii
E. Bartonella quintana
Match the following vector – chiggers, red mites – with Rickettsia
A. *Orientia tsutsugamushi
B. Coxiella burnetii
C. Rickettsia rickettsii
D. Rickettsia prowazekii
E. Bartonella quintana
527.
Match Orientia tsutsugamushi with the vector:
A. Cattle, sheep, goats
B. Flying squirrels, louse
C. Dogs, rodents, wood/dog tick
D. *Chiggers, red mites
E. No correct answer
528.
Match Coxiella burnetii with the vector:
A. *Cattle, sheep, goats
B. Flying squirrels, louse
C. Dogs, rodents, wood/dog tick
D. Chiggers, red mites
E. No correct answer
529.
Match Rickettsia prowazekii with the vector:
A. Cattle, sheep, goats
B. *Flying squirrels, louse
C. Dogs, rodents, wood/dog tick
D. Chiggers, red mites
E. No correct answer
530.
Match Rickettsia rickettsii with the vector:
A. Cattle, sheep, goats
B. Flying squirrels, louse
C. *Dogs, rodents, wood/dog tick
D. Chiggers, red mites
E. No correct answer
531.
A 10-year-old boy in Virginia presents with a rash, fever, and severe headache that began several
days ago. The rash began on his palms and soles and has now spread to his trunk. His pediatrician also
notes conjunctival redness, and lab studies show proteinuria. The boy’s history is significant for a hike
in the woods a week ago. The child is given tetracycline and his diagnosis is confirmed by a Weil-Felix
test. Which of the following is the most likely cause?
A. Orientia tsutsugamushi
B. Coxiella burnetii
C. *Rickettsia rickettsii
D. Rickettsia prowazekii
E. Rickettsia acari
532.
A cattle farmer goes to the doctor complaining of mild cough and fever. He says that the fever
began abruptly several days ago. His occupation as cattle slaughterer leads the doctor towards a
diagnosis, and tetracycline is administered. The diagnosis is confirmed by serology and a negative WeilFelix test. Which of the following is the most likely cause?
A. Orientia tsutsugamushi
B. *Coxiella burnetii
C. Rickettsia rickettsii
D. Rickettsia prowazekii
E. Rickettsia sibirica
533.
A Kosovo refugee sees a volunteer camp doctor complaining of a rash spreading outward from
his trunk but sparing his palms and soles. Two days ago, he experiences abrupt onset of fever,
headaches, and confusion. On physical exam, the doctor discovers lice in the man’s hair. The doctor
treats with a delousing regimen and tetracycline. Were he at a hospital, he might confirm the diagnosis
with a Weil-Felix test. Which of the following is the most likely cause?
A. Orientia tsutsugamushi
B. Coxiella burnetii
C. Rickettsia rickettsii
D. *Rickettsia prowazekii
E. Bartonella quintana
534.
The Chlamydiaceae life cycle has elemental bodies (EBs) that are ____ and reticulate bodies
(RBs) that are ____.
A. Metabolically active and infection; Metabolically inactive and noninfectious
B. *Metabolically inactive and infection; Metabolically active and noninfectious
C. Metabolically active and noninfection; Metabolically inactive and infectious
D. Metabolically inactive and noninfection; Metabolically active and infectious
E. No correct answer
535.
In the life cycle of Chlamydiaceae, ____ bind to cell receptors triggering endocytosis. ____
inhibit lysosome fusion and form ___, which replicate by binary fission and form ____ that cause the
cell to lyse.
A. *EBs; EBs; RBs; EBs;
B. EBs; RBs; RBs; EBs;
C. RBs; EBs; EBs; RBs;
D. RBs; RBs; EBs; RBs;
E. RBs; RBs; EBs; EBs;
536.
Chlamydia uses ATP for energy in order to construct DNA and proteins as well as encoding their
own ribosomes. This makes Clamydia which of the following?
A. Extracellular pathogen
B. *Obligate intracellular parasite
C. Obligate extracellular parasite
D. Facultative intracellular parasite
E. No correct answer
537.
A woman is brought to the ER complaining of vaginal discharge and RUQ abdominal pain. On
history, the patient reports having many sexual partners. Pelvic exam reveals cervical motion
tenderness, and labs of vaginal discharge detect numerous PMNs but no organisms on Gram stain. The
doctor makes a diagnosis based on these findings and administers doxycycline and ceftriaxone. Later,
surgeons, concerned about the patient’s abdominal pain, rule out cholecystitis by imaging, but
laparoscopy reveals adhesions around the patient’s liver capsule. Which of the following is the most
likely cause?
A. Chlamydia psittaci
B. *Clamydia trachomatis
C. Clamydia pneumoniae
D. All answers are correct
E. No correct answer
538.
A bird shop owner visits his doctor complaining of a headache, fever, and dry cough that has
worsened over the last few days. The patient also complains of a sore throat and muscle aches. A
physical exam reveals bilateral rales upon auscultation and mild splenomegaly. The doctor orders a
CXR that reveals a patchy pneumonitis. Diagnosis is confirmed with serological tests. The patient is
administered tetracycline and the fever diminishes within 2 days. Which of the following is the most
likely cause?
A. *Chlamydia psittaci
B. Clamydia trachomatis
C. Clamydia pneumoniae
D. All answers are correct
E. No correct answer
539.
A 22-year-old student presents with a nonproductive cough, fever, and sore throat. CXR
demonstrates diffuse interstitial infiltrate. Sputum Gram stain shows many PMNs but no organism, and
a Giemsa stain reveals intracytoplasmic inclusions in epithelial cells. Doxycycline treatment is begun.
Which of the following is the most likely cause?
A. Chlamydia psittaci
B. Clamydia trachomatis
C. *Clamydia pneumoniae
D. All answers are correct
E. No correct answer
540.
Which of the following is NOT used for laboratory diagnosis of C. trachomatis?
A. Microscopy of Gram-negative rods with no peptidoglycan cell wall
B. Molecular amplification (e.g. PCR)
C. Cell culture using certain cell lines (e.g. nonciliated columnar, cuboidal)
D. Antigen test (e.g. ELISA, fluorescence)
E. *Vaginal specimen cytology
541.
The main carrier site on the human body for strains of potentially pathogenic Staphylococcus
aureus is the
A. oral cavity
B. *throat posterior nasopharynx)
C. nasal membranes
D. gastrointestinal tract
E. vagina
542.
The carrier site in humans for pathogenic Neisseria meningitidis is the
A. conjunctiva
B. *nasopharynx
C. urogenital tract
D. blood
E. meninges
543.
This bacterium, although usually not considered as normal flora, frequently colonizes the
stomach and is thought to be the cause of gastric and duodenal ulcers.
A. Lactobacillus acidophilus
B. Pseudomonas aeruginosa
C. Escherichia coli
D. Vibrio cholerae
E. *Helicobacter pylori
544.
Silver nitrate or an antibiotic is put into the eyes of newborn infants to prevent infection by
A. Doderlein's bacillus (Lactobacillus acidophilus)
B. Herpes simplex virus
C. *Neisseria gonorrhoeae
D. Chlamydia trachcomatis
E. Staphylococcus aureus
545.
The fimbriae of enterotoxigenic E. coli are essential to the bacterium when it causes disease
because
A. *they are needed for initial attachment of the bacteria to the gastrointestinal epithelium
B. they activate host adenylate cyclase enzymes leading to disruption of cellular permeability
C. they make the bacteria resistant to phagocytic killing and digestion by white blood cells
D. they convert GI tract components (bile) to substances which provoke
E. they allow the bacteria to swim "upstream" against the peristaltic action of the GI tract thereby
remaining established in the GI tract
546.
The fibrin coat that can be formed by coagulase-positive staphylococci and the hyaluronic acid
capsule of Streptococcus pyogenes are pathogenic strategies to
A. A. promote colonization of a host
B. cause direct damage to host cells during pathogenesis
C. hide bacterial antigens from the host immune tissues
D. *survive as intracellular parasites !!!!
E. alter or change their surface antigens within the course of an infection
547.
Leukocidins are
A. enzymes contained in the lysosomes of phagocytes to kill ingested bacteria
B. proteins produced by bacteria that kill closely-related bacteria
C. proteases produced by bacteria which destroy host immunoglobulins
D. enterotoxins produced by Staphylococcus aureus involved in food-borne disease
E. *substances produced by pyogenic bacteria that kill phagocytes
548.
The streptococcal invasin which behaves as a "spreading factor" by breaking down the
framework of connective tissues is called
A. collagenase
B. streptokinase
C. streptolysin
D. erythrogenic toxin (pyogenic exotoxin)
E. *hyaluronidase
549.
A primary determinant of virulence in Streptococcus pyogenes, which is involved in adherence,
resistance to phagocytosis and antigenic variation, is
A. streptokinase
B.
C.
D.
E.
lipopolysaccharide (endotoxin)
*M-protein
Protein A
coagulase
550.
The large volume of fluid lost by diarrhea during infection with Vibrio cholerae
A. is a consequence of fluid replacement during treatment of the disease and does not result directly
from activity of the cholera toxin
B. results from electrolytes binding to the intestinal enterocytes which upsets their water retention
capability
C. is caused when the vibrios bind to the intestinal epithelium and physically or mechanically block
the uptake of fluids by the gut epithelial cells
D. *follows activation of adenylate cyclase by cholera toxin and the subsequent effect of cyclic
AMP on water and salt balances of the host cells
E. results from neurotoxic effects of the cholera toxin on the central nervous system
551.
The similarity between the toxic shock syndrome toxin (TSST), the staphylococcal enterotoxins,
and the erythrogenic toxin (pyogenic exotoxin) is
A. they are all produced by Staphylococcus aureus
B. *they stimulate the immune system in a similar manner as superantigens
C. the pathology of the diseases that they cause is identical
D. they are all neurotoxins
E. they are the same (identical) toxin produced by three different organisms
552.
Which tissue in a human is free from colonization by microbes (normal flora) because the
organisms lack normal access to the tissue?
A. *blood (vascular system)
B. colon
C. stomach
D. lower respiratory tract
E. urinary tract (urethra)
553.
Which tissue is normally free from colonization by microorganisms (normal flora) because of the
effectiveness of the host constitutive defenses?
A. upper respiratory tract (throat, pharynx)
B. *lower respiratory tract (lungs)
C. upper gastrointestinal tract
D. lower gastrointestinal tract
E. vagina
554.
The predominant bacteria in the mouth, GI tract (colon), and skin, respectively, are
A. staphylococci, streptococci, and corynebacteria
B. streptococci, E. coli, and staphylococci
C. *lactic acid bacteria, Bacteroides, and staphylococci
D. staphylococci, E. coli, and streptococci
E. neisseriae, enterococci, and clostridia
555.
The most important benefit that the human gastrointestinal flora provide for their host is
A. digestion of dietary cellulose
B. production of endotoxin that produces toxemia
C. production of dietary protein
D. *antagonism against colonization by potential pathogens
E. production of antibodies
556.
The bacterial product that prevents colonization of the vagina by potentially pathogenic yeasts is
A. bacteriocin
B. peroxide
C. TSST toxin
D. lysozyme
E. *lactic acid
557.
The main carrier site on the human body for strains of potentially pathogenic Neisseria
meningitidis is the
A. nasal membranes
B. *throat (posterior nasopharynx)
C. oral cavity
D. gastrointestinal tract
E. vagina
558.
In the pathogenesis of Helicobacter pylori what is the colonization site in the host?
A. nasal sinuses
B. *stomach
C. lower intestine
D. throat
E. respiratory tract
559.
What is the colonization site of Corynebacterium diphtheriae, the agent of diphtheria?
A. skin
B. urethra
C. eye
D. *throat
E. all are false
560.
A determinant of virulence of Streptococcus pneumoniae which allows the bacteria to resist
engulfment by phagocytes is
A. fimbriae
B. *a polysaccharide capsule
C. production of TSST exotoxin
D. coagulase
E. neuraminidase
561.
The fimbriae of pathogenic Neisseria gonorrhoeae are apparently essential to the bacterium when
it produces the disease gonorrhea because
A. *they are responsible for initial attachment of the bacteria to the urethral or cervical epithelium
B. they cause the production of pus which is characteristic of gonorrhea
C. they make the bacteria resistant to phagocytic killing and digestion by white blood cells
D. D. they convert urinary tract components (urine) to substances which provoke symptoms of
disease
E. E. they allow the bacteria to swim "upstream" against the flow of urine and thereby remain
established in the urinary tract
562.
The clostridial invasin that dissolves the framework of muscle is
A. botulinum toxin
B. tetanus toxin
C. *hyaluronic acid
D. neuraminidase
E. collagenase
563.
Both the cholera toxin and the E. coli LT toxin
A. have an A+B subunit arrangement
B. * are identical in their primary structure
C. are ADP-ribosylating toxins
D. have an enzymatic mechanism of action
E. all are true
564.
The main effect of E. coli and Vibrio cholerae enterotoxin on host cells of the gastrointestinal
tract that leads to the pathology of the diseases, is to
A. inhibit protein synthesis
B. *cause fluid and electrolyte imbalance
C. cleave host cell membranes
D. act as superantigens to trigger an overwhelming immunological reaction
E. initiate a localized inflammatory response in the intestine
565.
The portion of the bacterial lipopolysaccharide (LPS) that is responsible for the toxicity of the
molecule is
A. *lipid A
B. lipoteichoic acid
C. O polysaccharide
D. Omp A
E. N-acetylglucosamine (NAG)
566.
The portion of lipopolysaccharide (endotoxin) molecule that is responsible for a bacterium’s
antigenic specificity, as well as the existence of multiple serotypes (serovars) among Gram-negative
pathogens, is
A. lipid A
B. K antigen
C. *O polysaccharide
D. R antigen
E. H antigen
567.
What bacterial structure or substance is primarily associated with antigenic variation in the
Group A streptococci?
A. outer membrane protein (omp)
B. streptokinase
C. hyaluronic acid capsule
D. *Polysaccharide
E. M-protein
568.
A reason not to administer beta lactam antibiotics for a Gram-negative septicemia (blood-borne
infection), unless there is no other alternative, is
A. the antibiotic eliminates the normal flora
B. *beta lactam antibiotics are ineffective against Gram-negative bacteria
C. the lysis of bacterial cells increases the activity of bacterial LPS
D. Complement activation cannot occur in the presence of the antibiotic
E. the antibiotic suppresses the immune response necessary to eliminate the pathogen
569.
Which of the following bacterial toxins behaves as a superantigen through its stimulation of a
very large fraction of the host T-cell population?
A. Streptococcal streptolysin
B. Salmonella LPS (endotoxin)
C. Pseudomonas Exotoxin A
D. *Staphylococcal toxic shock syndrome toxin
E. E. coli O157 H:7 shiga toxin
570.
Haemolytic uraemic syndrome is caused by:
A. enteropathogenic Escherichia coli.
B. enterotoxigenic E. coli.
C. enteroinvasive
D. *verotoxigenic E. coli.
E. enteroaggregative E. coli.
571.
Which of the following bacteria is/are primarily human pathogens?
A. Salmonella Typhi.
B. S. Paratyphi A.
C. S. Paratyphi B.
D. Shigella
E. *All are true.
572.
Which of the following media is/are used for blood culture in cases of enteric fever?
A. *Bile broth.
B. Tetrathionate broth.
C. Selenite-F broth.
D. Sugar broth.
E. All are true.
573.
For determining the serotype of infecting organism, detection of which agglutinins is more
important in Widal test?
A. *O.
B. H.
C. Fimbrial.
D. M.
E. Vi
574.
Bipolar staining is characteristic of:
A. *Yersinia peslis.
B. Proteus mirabilis.
C. Pseudomonas aeruginosa.
D. Vibrio cholerae
E. all are true.
575.
Scalded skin syndrome is due to which toxin of Staphylococcus aureus?
A. *Epidermolytic toxin.
B. Enterotoxin.
C. Leucocidin.
D. Haemolysin
E. Necrotoxin
576.
Isolation of pneumococci from clinical specimens may be attempted by intraperitoneal
inoculation
A. rabbits.
B. rats.
C. cell culture.
D. sheep.
E. *mice
577.
“Medusa head” appearance of the colonies is characteristic of:
A. Proteus mirabilis.
B. Clostridium tetani.
C. *Bacillus anthracis.
D. Pseudomonas aeruginosa.
E. C. botulini
578.
Typical drumstick appearance of bacilli is observed in:
A. Clostridium perfringens.
B. C. tetani.
C. *С. botulinum.
D. C. histolyticum.
E. C. difficilae
579.
Pneumonic plague can be transmitted from man to man by:
A. droplet infection.
B. inoculation.
C. ingestion.
D. flea bite
E. *all of the routes.
580.
Which of the following bacteria can cause infective type of food poisoning?
A. *Salmonella enteritidis.
B. Staphylococcus aureus.
C. Clostridium botulinum.
D. Clostridium perfringens
E. All are true.
581.
Most important complication/s of enteric fever is/are:
A. intestinal perforation.
B. haemorrhage.
C. circulatory collapse.
D. * All are true.
E. All are false
582.
In enteric fever, Salmonella may be isolated from:
A. urine.
B. faeces.
C. blood.
D. bile
E. *All are true.
583.
Which of the following serotypes of Salmonella can cause gastroenteritis?
A. S. Enteritidis.
B. S. Newport.
C. S. Typhimurium.
D. *S. cholerae suis
E. All are true.
584.
Most strains of Staphylococcus aureus show:
A. a golden-yellow pigment.
B. *?-haemolysis on sheep blood agar.
C. phosphatase production.
D. novobicin resistance
E. all are true.
585.
Thin, slender and gram-positive bacilli possessing metachromatic granules and showing Chinese
letter arrangement are characteristic of:
A. Mycobacterium tuberculosis.
B. *Corynebacterium diphtheriae.
C. Bacillus anthracis.
D. Clostridium perfringens.
E. Bordetella pertussis
586.
A positive Schick test implies that the person is:
A. A. immune and non-hypersensitive.
B. *susceptible and non-hypersensitive.
C. immune and hypersensitive.
D. non-immune and hypersensitive.
E. healthy
587.
Cholera toxin resembles which of the following toxins?
A. *Labile toxin of Escherichia coli.
B. Stable toxin of E. coli.
C. Diphtheria toxin.
D. Tetanus toxin.
E. Staphylococcus enterotoxin
588.
Which of the following agents is the commonest cause of infective endocarditis?
A. Staphylococcus epidermidis.
B. Candida spp.
C. *Viridans group of streptococci.
D. Coliforms.
E. Rickettsia
589.
Infective-toxic type of food poisoning is caused by:
A. *Clostridium perfringens.
B. Salmonella Enteritidis.
C. Staphylococcus aureus.
D. Salmonella Dublin.
E. Yeasts
590.
Which of the following bacteria can grow in alkaline pH?
A. Lactobacilli.
B. *Vibrio cholerae.
C. Salmonella.
D. Shigella.
E. Neisseria
591.
The causative agent/s of gas gangrene is/are:
A. Clostridium perfringens.
B. C. novyi.
C. С. septicum.
D. C. histolyticum
E. *all are true.
592.
Dysentery like disease may be caused by
A. enteropathogenic Escherichia colt.
B. enterotoxigenic E. coli.
C. *enteroinvasive E. coli.
D. verotoxigenic E. coli.
E. enteroaggregative E. coli.
593.
Which of the following bacteria is negative for fermentation of mannitol?
A.
B.
C.
D.
E.
*Shigella dysenteriae.
S. flexneri.
S. boydii.
S. sonnei.
All are true.
594.
Which of the following specimens is/are most appropriate for culture of bacteria in first week of
enteric fever?
A. *Blood.
B. Urine.
C. Faeces.
D. CSF.
E. Bile
595.
Which of the following bacteria ferment mannitol anaerobically?
A. *Staphylococcus aureus.
B. S. epidermidis.
C. S. saprophyticus.
D. S. canis
E. All are false.
596.
Which of the following bacteria is/are implicated as causative agent/s of non-gonococcal
urethritis?
A. Chlamydia trachomatis.
B. Ureaplasmau urealyticum.
C. Mycoplasma hominis.
D. Herpes virus 2
E. *All are true.
597.
Which of the following are pyogenic cocci:
A. A. Streptococcus
B. Staphylococcus
C. Pneumococcus
D. Neisseria
E. *all of these
598.
The coagulase test is used to differentiate Staphylococcus aureus from
A. other staphylococci
B. *streptococci
C. micrococci
D. enterococci
E. pneumococci
599.
The symptoms in scarlet fever are due to
A. streptolysin
B. coagulase
C. pyrogenic toxin
D. alpha toxin
E. leucocidin
600.
Penicillin-resistant Staphylococcus can be treated with ______ without sensitivity testing.
A. Ampicillin
B. erythromycin
C. C. methicillin
D. *amoxycillin
E. no antibiotic
601.
Rheumatic fever damages the _______, and glomerulonephritis damages the______
A. skin, heart
B. joints, bone marrow
C. *heart valves, kidney
D. brain, kidney
E. heart, bone marrow
602.
______ hemolysis is the partial lysis of red blood cells due to bacterial hemolysins.
A. *Alpha
B.
C.
D.
E.
Beta
Gamma
Delta
Epsilon
603.
An effective vaccine exists to prevent infections from
A. Staphylococcus aureus
B. Streptococcus pyogenes
C. Neisseria. gonorrhoeae
D. *Streptococcus. pneumoniae
E. Micrococcus luteus
604.
Viridans streptococci commonly cause
A. pneumonia
B. meningitis
C. *subacute endocarditis
D. otitis media
E. arthritis
605.
Which genus of bacteria has pathogens that can cause blindness and deafness?
A. Branhamella
B. Staphylococcus
C. Streptococcus
D. *Neisseria
E. Shigella
606.
An important test for identifying Neisseria is
A. *production of oxidase
B. production of catalase
C. sugar fermentation
D. beta-hemolysis
E. alfa- hemolysis
607.
A complication of genital gonorrhea in both men and women is
A. i*nfertility
B. pelvic inflammatory disease
C. arthritis
D. blindness
E. urethritis
608.
The skin blotches in meningitis are due to
A. blood clots
B. *endotoxins in the blood
C. erysipelas
D. exotoxin in skin
E. E. skin invasion by N. meningitidis
609.
Which infectious agent of those covered in the chapter would most likely be acquired from a
contaminated doorknob?
A. Staphylococcus epidermidis
B. Streptococcus pyogenes
C. Neisseria meningitidis
D. Streptococcus pneumoniae
E. *Staphylococcus aureus
610.
What is the usual habitat of Endopore-forming bacteria that are agents of disease?
A. the intestine of animals
B. *soil
C. water
D. foods
E. dust
611.
Most Bacillus species are
A. true pathogens
B. opportunistic pathogens
C. *nonpathogens
612.
613.
614.
615.
616.
617.
618.
619.
620.
621.
D. commensals
E. saprophyticus
Many clostridial diseases require a/an ______ conditions for their development.
A. *anaerobic
B. aerobic
C. living tissue
D. low-pH
E. alkaline pH
Clostridium perfringens causes
A. angine
B. *enterocolitis, haemorrhagic syndrom
C. antibiotic-induced colitis
D. All are true
E. All are false
An infection peculiar to swine causes when transmitted to humans.
A. anthrax
B. diphtheria
C. *erysipeloid
D. plage
E. tuberculosis
Which infectious agent cause pseudomembranous collitis?
A. Mycobacterium tuberculosis
B. Corynebacterium diphtheriae
C. Mycobacterium leprae
D. *Clostridium difficile
E. Shigella sonnei
Which infectious agents cause food poising?
A. Bacillus anthracis
B. Clostridium tetani
C. *Clostridium perfringens
D. Streptococcus pyogenes
E. all of these
A unique characteristic of many isolates of Pseudomonas useful in identification is
A. drug resistance
B. fecal odor
C. *green pigment
D. gram staining
E. motility
A classic symptom of pertussis is
A. labored breathing
B. convulsions
C. headache
D. *paroxysmal coughing
E. redish of skin
The severe symptoms of pertussis are due to what effect?
A. irritation of the glottis by the microbe
B. pneumonia
C. *damage of function of the respiratory epithelium
D. blocked airways
E. E. heart disease
For Escherichia coli most impotent which antigens?
A. capsular
B. *somatic
C. flagellar
D. Vi
E. all are true
Which of the following bacterium is causative agent of dysenteriae?
A.
B.
C.
D.
E.
E. coli
Klebsiella
Proteus
Vibrio
*Shigella
622.
Which of the following represents a major difference between Salmonella and Shigella
infections?
A. incubation period
B. mode of transmission
C. *place of location in intestine
D. presence/absence of fever and diarrhea
E. the portal of entry
623.
Complications of typhoid fever are:
A. intestinal perforation
B. liver abscesses
C. both a and b
D. *neurological damage
E. sepsis
624.
Shigella is transmitted by
A. *infected food and water
B. flies
C. both a and b
D. air dropled
E. louse
625.
Lyme disease is caused by ______ and spread by ______.
A. Borrelia recurrentis, lice
B. *Borrelia burgdorferi, ticks
C. Borrelia burgdorferi, chiggers
D. Borrelia hermsii, ticks
E. Borrelia recurrentis, ticks
626.
Chlamydia trachomatis can attacks which structure(s)?
A. eye
B. urethra
C. fallopian tubes
D. lungs
E. *all of these
627.
Ornithosis is a _____ infection associated with ______
A. rickettsial, parrots
B. chlamydial, mice
C. *chlamydial, birds
D. rickettsial, flies
E. chlamydial, rats
628.
Mycoplasmas demage next structure of host cells.
A. nucleus
B. cell walls
C. ribosomes
D. *cell membranes
E. mitochondria
629.
A child develops pneumonia. The bacterium Streptococcus pneumoniae is cultured from the
patient’s sputum. Cells of the cultured bacteria have thick polysaccharide capsules. How did the
presence of capsules promote development of serious disease?
A. Prevented binding of antibodies to the bacteria.
B. Prevented initiation of a humoral immune response.
C. Prevented activation of helper T cells.
D. *Prevented phagocytosis by neutrophils.
E. Prevented mast-cell degranulation.
630.
Water to be used for parenteral injection must sterilized to kill living microbes and then further
purified to remove non-living bacterial components. Of those listed below, which is the most toxic?
A. *Lipopolysaccharide.
B. Polysaccharides of capsules.
C. Plasma-membrane lipids.
D. Proteins of the outer membrane.
E. Nucleic acids
631.
A child at-risk for Tetanus is treated with Tetanus immune globulin (human). What is a major
advantage of this method for immunization over the use of Tetanus toxoid?
A. Poses a reduced risk of serum sickness.
B. Provides longer-lasting immunity.
C. *Provides protection more rapidly.
D. Results in higher antibody titer.
E. Also provides secretory IgA for mucosal immunity.
632.
A child under treatment for leukemia is treated with Tetanus immune globulin (human). Which
phrase best describes the immunity that is produced?
A. Innate and specific.
B. Innate and humoral.
C. Innate and cell-mediated.
D. *Acquired and humoral.
E. Acquired and cell-mediated.
633.
An elderly man develops pneumonia and septicemia. Gram stain of sputum contains many
neutrophils and Gram-positive cocci, in pairs. Blood and sputum cultures grow out a Gram-positive
coccus, alpha-hemolytic on sheep blood agar, and catalase-negative. Which organism below is most
likely?
A. Staphylococcus epidermidis.
B. Staphylococcus aureus.
C. *Streptococcus pneumoniae.
D. Streptococcus pyogenes.
E. Streptococcus agalactiae.
634.
Staphylococcus aureus is easily transmitted within the hospital environment. Which feature of
this bacterium is most largely responsible for its ease of spread?
A. *Resistance to heat, cold, and drying.
B. Ability to colonize the digestive tract.
C. Presence of an outer membrane impermeable to most disinfectants.
D. Production of extracellular polysaccharide which allows it to adhere tightly to surfaces.
E. Ability to form spores which are resistant to disinfectants and easily dispersed.
635.
A stool sample is plated on standard Endo-agar plates. After overnight incubation some of the
colonies are dark pink in color, others are pale, nearly colorless. What can you conclude about the
bacteria that produced dark-pink colonies?
A. Gram-positive.
B. *Ferment lactose.
C. Not likely to be ‘normal flora’.
D. Non-motile.
E. Produce capsules.
636.
A 35-year-old woman presents with a history of increasing respiratory distress and cough
productive of sputum. Chest X-ray shows evidence of bilateral pneumonia. Cultures of blood and
sputum on Chocolate agar grow out slender Gram-negative rods; cultures on standard sheep blood agar
are negative. Which bacterium is most likely to be the cause of her infection?
A. Mycoplasma pneumoniae.
B. Chlamydia pneumoniae.
C. *Haemophilus influenzae.
D. Escherichia coli.
E. Streptococcus pneumoniae.
637.
You suspect Chlamydia infection in a sexually-active young woman. Which test would be most
likely to provide results which would confirm this diagnosis?
A. Agglutination test for anti-cardiolipin antibodies.
B.
C.
D.
E.
*PCR test of nucleic acids present in a urine sample.
Test of a blood sample for ‘cold agglutinins”.
Gram-stained smear of discharge from the cervix.
Culture of exudate from the cervix on Thayer-Martin agar.
638.
In the morning mss R. had become ill, with high fever, severe headache, and stiff neck. She was
admitted to the hospital. Later that day she developed rash, at first petechial and then pupuric. Gram
stain of CSF showed many white cells and Gram-negative cocci, many in pairs. Which organism is most
likely to be the cause of her infection?
A. Escherichia coli.
B. Haemophilus influenzae.
C. *Neisseria meningitidis.
D. Streptococcus agalactiae.
E. Streptococcus pneumoniae.
639.
A patient with septicemia goes into septic shock. Blood cultures later showed the pathogen to be
Escherichia coli. Which component of the bacteria was most likely to have produced shock?
A. Capsular polysaccharide.
B. Teichoic acid.
C. A superantigen toxin.
D. *Lipopolysaccharide [LPS].
E. Plasma membrane lipids.
640.
A patient has cellulitis of the left arm, persistent fever, and a heart murmur. He is a habitual user
of illegal drugs, which he self-administers intravenously. An echocardiogram shows a bacterial
vegetation on the aortic valve. Three blood cultures all grow an ?-hemolytic Gram-positive coccus,
catalasenegative. Which organism is most likely to have caused his infection?
A. Staphylococcus aureus.
B. *A Viridans-group Streptococcus.
C. Streptococcus pyogenes [Group A].
D. Streptococcus agalactiae [Group B].
E. Streptococcus bovis [Group D].
641.
Administration of which of the following vaccines would be contra-indicated in an patient with
impaired cell-mediated immunity?
A. Pneumococcal vaccine (pediatric).
B. Pneumococcal vaccine (adult).
C. *BCG vaccine against tuberculosis.
D. Tetanus toxoid.
E. Acellular Pertussis vaccine.
642.
A sexually-active woman develops a urinary tract infection which ascends to the kidneys. Blood
culture yields a ?-hemolytic Gram-negative rod. In this situation, which pathogen is most common?
A. *Escherichia coli.
B. Klebsiella pneumoniae.
C. Pseudomonas aeruginosa.
D. Salmonella enteritidis.
E. Serratia marcescens.
643.
A four-year-old boy was brought to the emergency room with a history of bloody diarrhea over
the preceding two days. A fecal smear contained numerous red cells and neutrophils. Stool culture on
Endo agar produced lactose-negative colonies amid colonies of ‘normal intestinal flora’. Which of the
organisms below is most likely to be the cause of his illness?
A. Enteropathogenic E. coli
B. Balantidium coli.
C. Entamoeba histolytica
D. Giardia lamblia.
E. *Shigella.
644.
A child develops a “cold” which progresses to severe pharyngitis. Pharyngeal exudate forms a
tough ‘membrane’, difficult to remove without causing bleeding. Culture of a throat swab on selective
tellurite agar produces abundant black colonies. Other cultures produce only normal flora. Which
organism is most likely to have caused this infection?
A. Actinomyces israelii.
B.
C.
D.
E.
Bordetella pertussis.
Candida albicans.
*Corynebacterium diphtheriae.
Mycobacterium avium/intracellulare.
645.
A patient has rapidly spreading soft-tissue infection with gas in infected tissue. Fluid from a
blister contains many large Gram-positive rods which grow on sheep blood agar anaerobically but not
aerobically. Which pathogen is most consistent with these findings?
A. Bacillus anthracis.
B. Bacillus cereus.
C. Clostridium difficile.
D. *Clostridium perfringens.
E. Listeria monocytogenes.
646.
Untreated pharyngitis produced by Group A streptococci can result in later development of
Acute rheumatic fever, created by cross-reaction of anti-streptococcal antibodies with heart tissue.
Which streptococcal antigen stimulates formation of these cross-reactive antibodies?
A. Group A carbohydrate.
B. Flagella.
C. *M protein
D. Peptidoglycan.
E. Teichoic acid.
647.
A child is diagnosed with Pertussis. How was this infection most likely to have been acquired?
A. Bite of a dog or cat.
B. Consumption of dairy products made from unpasteurized milk
C. Contact with livestock or animal products such as leather or wool.
D. *Inhalation of respiratory droplets of another human being.
E. Release of oral flora into the bloodstream by dental work
648.
Infections with Salmonella enterica, serotype typhi, spread throughout the body. A key to the
ability of serotype typhi to spread systemically is its ability to multiply intracellularly. Multiplication in
which cell type(s) is principally responsible for systemic spread?
A. *Monocytes/macrophages.
B. Basophils.
C. Enterocytes.
D. Erythrocytes.
E. Neutrophils.
649.
A 25-year-old female presented with a three-day history of fever, headache and a non-productive
cough. X-rays show bilateral diffuse lung infiltrates. Culture of a throat swab (on sheep blood and
chocolate agars) revealed only “normal oral flora”. Penicillin G was prescribed and the patient sent
home. Her illness did not respond to this antibiotic. She was then successfully treated with
erythromycin. Which organism is most likely to have caused her illness?
A. *Mycoplasma pneumoniae.
B. Haemophilus influenzae.
C. Mycobacterium tuberculosis.
D. Streptococcus pyogenes.
E. Streptococcus pneumoniae.
650.
A vacationer has “Traveler’s diarrhea” produced by enterotoxigenic E. coli. His profuse watery
diarrhea is produced by a protein exotoxin secreted by this bacterium. Which statement below best
describes the effect of this exotoxin?
A. Kills enterocytes and produces ulceration and inflammation.
B. Paralyzes phagocytosis by neutrophils.
C. *Stimulates ion transport by enterocytes into the intestinal lumen.
D. Blocks adsorption of nutrients by enterocytes.
E. Causes rearrangement of the enterocyte cytoskeleton and disappearance of the brush border.
651.
The severe diarrhea of cholera is produced by a protein exotoxin that acts on enterocytes. Which
statement below best describes the effect of Cholera toxin?
A. Alters the actin cytoskeleton.
B. Inactivates ribosomes.
C. Proteolytic cleavage of a specific cellular protein.
D. *Stimulates adenyl cyclase.
E. Stimulates guanyl cyclase.
652.
A neonate develops septicemia. Blood cultures produce a ?-hemolytic Gram-positive coccus. It
is catalase negative. Which test would best confirm the identity of the pathogen as a Group B
Streptococcus?
A. *Synergy of hemolysin with the hemolysin of Staphylococcus aureus [CAMP test].
B. Bile-esculin test.
C. Bacitracin sensitivity.
D. Optochin sensitivity.
E. Novobiocin sensitivity.
653.
A individual may have repeated infections with Neisseria gonorrhoeae, despite the fact that each
infection gives rise to an immune response. By which mechanism does the gonococcus evade protective
immunity?
A. Thick capsule prevents binding of antibodies to the cell surface.
B. Pili adhere to epithelial cells despite binding of antibodies.
C. Capsular polysaccharide is identical to polysaccharides of mammalian cells.
D. Outer membrane lacks any antigenic components.
E. *The surface antigens present change continually, as a result of pre-programmed changes in
DNA.
654.
A medical student with a three-week history of respiratory illness is treated with erythromycin [a
macrolide]. Which phrase best describes the process inhibited by this drug?
A. Transcription by bacterial RNA polymerase.
B. Supercoiling of bacterial DNA.
C. Cross-linking of peptidoglycan.
D. Polymerization of peptidoglycan.
E. *Peptide bond formation by bacterial ribosomes.
655.
An elderly resident of a nursing home develops pneumococcal pneumonia. This illness might
have been prevented had the patient been immunized against this organism. Which antigens of S.
pneumoniae are included in the adult vaccine?
A. M-proteins.
B. Intact heat-killed bacteria.
C. Toxoids produced from superantigen toxins.
D. *Capsular polysaccharides.
E. Cell-associated (C) carbohydrates.
656.
Before the advent of immunization, outbreaks of meningococcal disease were frequent in
military camps. A factor in development of such outbreaks is the ability of Neisseria meningitidis to
establish an asymptomatic ‘carrier state’. What is the predominant site of carriage of Neisseria?
A. Urethral epithelium.
B. Gall bladder.
C. Large intestine.
D. *Nasopharynx.
E. Meninges and choroid plexus
657.
Chlamydia trachomatis may be cultured on monolayers of human cells. If infected cells were
examined by staining and light microscopy, what would you be most likely to observe?
A. A membrane-bounded inclusion body, within the nucleus.
B. *A membrane-bounded inclusion body, within the cytoplasm.
C. Rod shaped Gram-positive bacilli, free within the cytoplasm.
D. Gram-negative cocci, within the lumen of the endoplasmic reticulum.
E. Cyst forms inside lysosomes.
658.
An infant is brought to the emergency room, cyanotic and with poor muscle tone.
659.
Which condition is most likely given these findings?
A. Antibiotic-associated colitis.
B. Diphtheria.
C. Anthrax.
D. *Botulism.
E. Tetanus.
660.
In what way do Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae
most closely resemble each other?
A. *Polysaccharide capsules.
B. Lipopolysaccharide in their outer membranes.
C. Teichoic acid in their envelopes.
D. Thick peptidoglycan in their cell walls.
E. Motility due to flagella.
661.
A patient becomes infected with Salmonella enterica serotype typhi. Which condition would
most strongly favor development of a “chronic carrier state” with this organism?
A. Age over 70 years.
B. Infection via the respiratory route.
C. *Gallstones.
D. Kidney stones.
E. Chronic pulmonary disease.
662.
A patient has an abscess from which Bacterioides fragilis is isolated. Which condition is most
likely to have facilitated infection by this organism?
A. Treatment with trimethoprim/sulfa.
B. *Tissue ischemia.
C. Presence of neutrophils.
D. Antibiotic treatment for another bacterial infection.
E. Colonization of the large intestine with spores of this organism.
663.
A patient develops pneumonia caused by Streptococcus pneumoniae. The predominant virulence
factor of this organism is a thick capsule . Which phrase best describes the role of this capsule in
virulence?
A. Aids in acquisition of iron.
B. Toxic to lung epithelial cells
C. Identical to human polysaccharide, so is non-immunogenic.
D. *Reduces phagocytosis by neutrophils.
E. Inhibits activation of Complement.
664.
A patient has a peptic ulcer. Which organism is most likely to have created this lesion?
A. Campylobacter jejuni.
B. Enterococcus faecalis.
C. Escherichia coli.
D. *Helicobacter pylori
E. Salmonella enteritidis.
665.
A 50-year-old woman was treated for cystitis [caused by E. coli] with an oral broad-spectrum
antibiotic. Three weeks later she developed abdominal pain and diarrhea. A stained smear of stool
contained many neutrophils. Cultures for bacterial pathogens were negative. A serological test of stool
for Clostridium difficile toxin was positive. Which of the following is most likely to have been the
immediately predisposing cause of this patient’s
F. difficile infection?
A. Colonization of her large intestine by antibiotic-resistant E. coli.
B. *Alteration of her intestinal flora by antibiotic treatment.
C. An allergic response to her antibiotic treatment.
D. Acquisition of an antibiotic-resistance plasmid (R-Factor) by C. difficile.
E. All are true
666.
Chancroid is caused by
A. Treponema pallidum
B. *Hemophilus ducreyi
C. Treponema pallidum
D. Clostridium sp.
E. All answers are true
667.
Which of the following statements best describes Streptococcus pneumoniae?
A. *bile soluble, optochin sensitive, capsulated
B. bile soluble, catalase negative, noncapsulated
C. bile soluble, gramnegative, optochin resistant
D. bile soluble, catalase positive, optochin sensitive
E. bile soluble, catalase negative, motily
668.
Which of the following is a pathogen of the oropharynx?
A. Streptococcus pneumoniae
B. *Streptococcus pyogenes
C. Streptococcus bovis
D. Streptococcus viridans
669.
What do endotoxins and exotoxins have in common?
A. secreted into the medium
B. *cause damage to the host
C. heat stable
D. heat resistent
E. contain polysaccharide
670.
Which virulence factor results in the symptoms of Staphylococcal food poisoning?
A. exfoliative exotoxin
B. hyaluronidase
C. endotoxin
D. *enterotoxin
E. neurotoxin
671.
Which of the following best describes the pathogenesis of acute rheumatic fever?
A. *characterized by inflammation of the heart and/or the joints
B. due to an immunologic cross reaction between heart muscle and Staphylococcus aureus
C. involves B-hemolytic Streptococci growing in the heart
D. is a complication of Group A Streptococcal skin disease as well as pharyngitis
E. tonsilitis is first stage of development of rheumatic fever
672.
Which test result would rule out an Enterococcus isolate?
A. growth in 6.5% NaCl
B. *oxidase positive
C. catalase negative
D. PYR positive
E. motility
673.
Which of the following tests may be used to differentiate Salmonella typhi from Shigella
species?
A. glucose fermentation
B. gas production from glucose
C. *motility
D. citrate utilization
E. color of colonies on Endo medium
674.
Which of the following descriptions best fits a typical strain of Escherichia coli?
A. non-motile, aerogenic, lactose fermenting mucoid colony
B. motile, anaerogenic, non-lactose fermenting, indole positive
C. *motile, aerogenic, lactose fermenting, indole positive
D. motile, aerogenic, non-lactose fermenting, citrate negative
E. non-motile, ferments lactose slowly, gramnegative
675.
Hemolytic uremic syndrome is caused by which of the following bacterium?
A. Campylobacter jejuni
B. *Escherichia coli 0157
C. Helicobacter pylori
D. Salmonella typhi
E. Ureaplasma
676.
What is the most common cause of urinary tract infections?
A. Staphylococcus saprophyticus
B. Escherichia coli
C. *Enterococcus fecalis
D. Streptococcus bovis
E. Staphylococcus epidermidis
677.
Which of the following result(s) best describe(s) the listed organism?
A. Campylobacter jejuni - gram positive gull wings
Shigella Sonneii – mannitol negative H2S (wk)
*E coli 0157 – lactose positive, indole positive
Yersinia enterocolitica –sporulated, colony sick yellow
Clostridium perfringens – aerobes, sporulated
678.
Which of the following tests may be used to differentiate Salmonella paratyphi from Shigella
species?
A. Fermentation of glucose
B. gas production from glucose
C. gram staining
D. citrate utilization of Simmons’ citrate agar
E. shape
679.
Which of the following descriptions best fits a typical strain of Escherichia coli?
A. motile, aerogenic, non-lactose fermenting, citrate negative
B. non-motile, aerogenic, lactose fermenting mucoid colony
C. motile, anaerogenic, non-lactose fermenting, indole positive
D. *motile, aerogenic, lactose fermenting, indole positive
E. motile, anaerogenic, lactose fermenting, sporulated
680.
Syphilis is caused by which of the following?
A. Helicobacter pylori
B. Proteus mirabilis
C. *Treponema pallidum
D. Serratia marcesans
E. Treponema Vincentii
681.
Borellia burgdorferi causes which disease?
A. *Lyme Disease
B. Rocky Mountain Spotted Fever
C. Hanta
D. Rabies
E. Relapsing fever
682.
How is leptospirosis, caused by Leptospira interrogans, transmitted?
A. Tick bite
B. *Contaminated urine in food or water
C. Undercooked meat
D. Inhaled aerosol
E. louse feces
683.
What is the most common human pathogen/opportunist?
A. Staphylococcus aureus
B. Steptococcus pneumoniae
C. *Pseudomonas aeruginosa
D. Escherichia coli
E. Enterococcus
684.
Which of the following is NOT true about Bordetella pertussis?
A. Causes Whooping Cough
B. Attaches to ciliated cells with capsules
C. Complications can include pneumonia, brain damage and death
D. *Gram negative anaerobe
E. Form pelicle on liquid (20 % blood broth) nutrient medium
685.
Which of the following is NOT true of Neisseria meningitidis?
A. Crosses the blood brain barrier
B. *Has 3 serotypes - A, B, Y
C. Colonizes nasopharynx
D. Predisposed groups include diabetics
E. Utilize glucose and mannitol
686.
Helicobacter pylori, a cause of peptic ulcers and gastric carcinoma, is diagnosed by which of the
following methods?
A. Serology (serum) test
B. Biopsy (invasive)
B.
C.
D.
E.
C. *Radioactive isotope C14 test
D. Bacteriological
E. All are true
687.
Which of the following does not occur when an individual is infected with Salmonella
enteriditis?
A. Endotoxins cause inflammation and fever
B. Enterotoxins cause diarrhea
C. Cytotoxins lyse endothelial cells lining the intestinal tract
D. *Proteolytic enzymes cause necrosis
E. Salmonellosis
688.
What is the primary cause of death from Salmonella typhi (Typhoid fever)?
A. *Hemorrhaging necrosis
B. DIC (disseminating intravascular coagulation)
C. Toxemia
D. High fever
E. Vomiting
689.
Which of the following members of the Clostridium family causes pseudomembranous colitis?
A. Clostridium tetani
B. *Clostridium difficile
C. Clostridium botulinum
D. Clostridium perfringens
E. Clostridium septicum
690.
Which of the following is NOT a major symptom of Corynebacterium diphtheriae?
A. Formation of a leathery pseudomembrane
B. Lesions on tonsils
C. *Flat, pink rash on abdomen
D. Inflammation of heart and nervous system
E. Toxic complication
691.
Which of the following methods is used to help clear an anaerobic infection?
A. Removal of dead tissue
B. Drainage of infected area
C. Oxidizing agents/hyperbaric chambers
D. Use of antibiotics
E. *All are true
692.
What causes gas gangrene?
A. *Clostridium perfringens
B. Leptospira interrogans
C. Staphylococcus aureus
D. Escherichia coli
E. Clostridium tetani
693.
An outbreak of sepsis caused by Staphylococcus aureus has occurred in the newborn nursery.
You are called upon to investigate. According to your knowledge of the normal flora, what is the MOST
likely source of the organism?
A. Colon
B. *Nose
C. Throat
D. Vagina
E. All are true
694.
Each of the statements about the classification of streptococci is correct EXCEPT:
A. Pneumococci {Streptococcus pneumoniae) are alpha-hemolytic and can be serotyped on the
basis of their polysaccharide capsules
B. Enterococci are group D streptococci and can be classified by their ability to grow in 6.5%
sodium chloride
C. Although pneumococci and the viridans streptococci are alpha-hemolytic, they can be
differentiated by the bile solubility test and their susceptibility to optochin
D. *Viridans streptococci are identified by Lance-field grouping, which is based on the C
carbohydrate in the cell wall
E. All are true
695.
Each of the following agents is a recognized cause of diarrhea EXCEPT:
A. Clostridium perfringens
B. *Enterococcus faecalis
C. Escherichia coli
D. Vibrio cholerae
E. All are true
696.
Each of the following organisms is an important cause of urinary tract infections EXCEPT:
A. Escherichia coli
B. Proteus mirabilis
C. Klebsiella pneumoniae
D. *Bacteroides fragilis
E. All are true
697.
Your patient is a 30-year-old woman with nonbloody diarrhea for the past 14 hours. Which one
of the following organisms is LEAST likely to cause this illness?
A. Clostridium difficile
B. *Streptococcus pyogenes
C. Shigella dysenteriae
D. Salmonella enteritidis
E. All are true
698.
Each of the following statements concerning Mycobacterium tuberculosis is correct EXCEPT:
A. After being stained with carbolfuchsin, M. tuberculosis resists decolorization with acid alcohol
B. M. tuberculosis has a large amount of mycolic acid in its cell wall
C. *M. tuberculosis appears as a red rod in Gram-stained specimens
D. M. tuberculosis appears as a red rod in acid-fast stained specimens
E. All are true
699.
Your patient has subacute bacterial endocarditis caused by a member of the viridans group of
streptococci. Which one of the following sites is MOST likely to be the source of the organism?
A. Skin
B. Colon
C. *Oropharynx
D. Urethra '
E. All are true
700.
A culture of skin lesions from a patient with pyoderma (impetigo) shows numerous colonies
surrounded by a zone of beta hemolysis on a blood agar plate. A Gram-stained smear shows grampositive cocci. If you found the catalase test to be negative, which one of the following organisms would
you MOST probably have isolated?
A. *Streptococcus pyogenes
B. Staphylococcus aureus
C. Staphylococcus epidermidis
D. Streptococcus pneumoniae
E. All are true
701.
The coagulase test, in which the bacteria cause plasma to clot, is used to distinguish
A. Streptococcus pyogenes from Enterococcus faecalis
B. Streptococcus pyogenes from Staphylococcus aureus
C. *Staphylococcus aureus from Staphylococcus epidermidis
D. Staphylococcus epidermidis from Neisseria meningitidis
E. All are true
702.
Which one of the following is considered a virulence factor for Staphylococcus aureus?
A. A heat-labile toxin that inhibits glycine release at the internuncial neuron
B. An oxygen-labile hemolysin
C. Resistance to novobiocin
D. *Protein A that binds to the Fc portion of IgG
E. All are true
703.
Five hours after eating fried rice at a restaurant, a 24-year-old woman and her husband both
developed nausea, vomiting, and diarrhea. Which of the following organisms is the MOST likely to be
involved?
A.
B.
C.
D.
E.
Clostridium perfringens
Enterotoxigenic Escherichia coli
*Bacillus cereus
Salmonella typhi
All are true
704.
For which one of the following enteric illnesses is a chronic carrier state MOST likely to
develop?
A. Campylobacter enterocolitis
B. Shigella enterocolitis
C. Cholera
D. *Typhoid fever
E. All are true
705.
Each of the following statements concerning chlamydiae is correct EXCEPT:
A. Chlamydiae are strict intracellular parasites because they cannot synthesize sufficient ATP
B. Chlamydiae possess both DNA and RNA and are bounded by a cell wall
C. trachomatis has multiple serotypes, but C psittaci has only one serotype
D. *Most chlamydiae are transmitted by arthropods
E. All are true
706.
Each of the following statements concerning Staphylococcus aureus is correct EXCEPT:
A. Gram-positive cocci in grapelike clusters are seen on Gram-stained smear
B. The coagulase test is positive
C. Treatment should include a (3-lactamase-resistant penicillin
D. *Endotoxin is an important pathogenetic factor
E. All are true
707.
Your patient is a 70-year-old man who underwent bowel surgery for colon cancer 3 days ago. He
now has a fever and abdominal pain. You are concerned that he may have peritonitis. Which one of the
following pairs of organisms is MOST likely to be the cause?
A. *Bacteroides fragilis and Klebsiella pneumoniae
B. Bordetella pertussis and Salmonella enteritidis
C. Actinomyces israelii and Campylobacter jejuni
D. Clostridium botulinum and Shigella dysente-riae
E. All are true
708.
A 65-year-old man develops dysuria and hematuria. A Gram stain of a urine sample shows
gram-negative rods. Culture of the urine on EMB agar reveals lactose-negative colonies without
evidence of swarming motility. Which one of the following organisms is MOST likely to be the cause of
his urinary tract infection?
A. Enterococcusfaecalis
B. *Pseudomonas aeruginosa
C. Proteus vulgaris
D. Escherichia coli
E. All are true
709.
A 25-year-old man complains of a urethral discharge. You perform a Gram stain on a specimen
of the discharge and see neutrophils but no bacteria. Of the organisms listed, the one MOST likely to
cause the discharge is
A. Treponema pallidum
B. *Chlamydia trachomatis
C. Candida albicans
D. Coxiella burnetii
E. All are true
710.
Two hours after a delicious Thanksgiving dinner of barley soup, roast turkey, stuffing, sweet
potato, green beans, cranberry sauce, and pumpkin pie topped with whipped cream, the Smith family of
four experience vomiting and diarrhea. Which one of the following organisms is MOST likely to cause
these symptoms?
A. Shigella flexneri
B. Campylobacter jejuni
C. *Staphylococcus aureus
D. Salmonella enteritidis
E. All are true
711.
The MOST important contribution of the capsule of Streptococcus pneumoniae to virulence is
A. To prevent dehydration of the organisms on mucosal surfaces
B. *To retard phagocytosis by polymorphonuclear leukocytes
C. To inhibit polymorphonuclear leukocyte chemo taxis
D. To accelerate tissue invasion by its collage-naselike activity
E. All are true
712.
The MOST important way the host circumvents the function of the pneumococcal
polysaccharide capsule is via
A. T lymphocytes sensitized to polysaccharide antigens
B. Polysaccharide-degrading enzymes
C. *Anticapsular antibody
D. Activated macrophages
E. All are true
713.
The pathogenesis of which one of the following organisms is MOST likely to involve invasion of
the intestinal mucosa?
A. Vibrio cholerae
B. *Shigella sonnei
C. Enterotoxigenic Escherichia coli
D. Clostridium botulinum
E. All are true
714.
Which one of the following organisms that infects the gastrointestinal tract is the MOST frequent
cause of bacteremia?
A. Shigella flexneri
B. Campylobacter jejuni
C. Vibrio cholerae
D. *Salmonella typhi
E. All are true
715.
Each of the following statements concerning Bacteroides fragilis is correct EXCEPT:
A. fragilis is a gram-negative rod that is part of the normal flora of the colon
B. *ragilis forms Endopores, which allow it to survive in the soil
C. The capsule of B. fragilis is an important virulence factor
D. fragilis infections are characterized by foul-smelling pus
E. All are true
716.
Each of the following statements concerning staphylococci is correct EXCEPT:
A. S. aureus is differentiated from S. epidermidis by the production of coagulase
B. S. aureus infections are often associated with abscess formation
C. The majority of clinical isolates of S. aureus elaborate penicillinase; therefore, presumpD. tive antibiotic therapy for S. aureus infections should not consist of penicillin G
E. *Scalded skin syndrome caused by S. aureus is due to enzymatic degradation of epidermal
desmosomes by catalase
717.
Each of the following statements concerning gram-negative rods is correct EXCEPT:
A. *Escherichia coli is part of the normal flora of the colon; therefore, it does not cause diarrhea
B. coli ferments lactose, whereas the enteric pathogens Shigella and Salmonella do not
C. Klebsiella pneumoniae, although a cause of pneumonia, is part of the normal flora of the colon
D. Proteus species are highly motile organisms that are found in the human colon and cause urinary
tract infections
E. All are true
718.
Five days ago a 65-year-old woman with a lower urinary tract infection began taking ampicillin.
She now has a fever and severe diarrhea. Of the organisms listed, which one is MOST likely to be the
cause of the diarrhea?
A. *Clostridium difficile
B. Bacteroides fragilis
C. Proteus mirabilis
D. Bordetella pertussis
E. All are true
719.
The pathogenesis of which one of the following diseases does NOT involve an exotoxin?
A.
B.
C.
D.
E.
Scarlet fever
*Typhoid fever
Toxic shock syndrome
Botulism
All are true
720.
Regarding the effect of benzylpenicillin (penicillin G) on bacteria, which one of the following
organisms is LEAST likely to be resistant?
A. Staphylococcus aureus
B. *Enterococcus faecalis
C. Streptococcus pyogenes
D. Neisseria gonorrhoeae
E. All are true
721.
Each of the following statements concerning chlamydial genital tract infections is correct
EXCEPT:
A. *Infection can be diagnosed by finding anti-chlamydial antibody in a serum specimen
B. Infection can persist after administration of penicillin
C. Symptomatic infections can be associated with urethral or cervical discharge containing many
polymorphonuclear leukocytes
D. There is no vaccine against these infections
E. All are true
722.
Which one of the following is NOT an important characteristic of either Neisseria gonorrhoeae
or Neisseria meningitidis?
A. Polysaccharide capsule
B. IgA protease
C. *M protein
D. Pili
E. All are true
723.
Which one of the following is NOT an important characteristic of Streptococcus pyogenes?
A. *Protein A
B. M protein
C. Beta-hemolysin
D. Polysaccharide group-specific substance
E. All are true
724.
Three organisms, Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus
influenzae. cause the vast majority of cases of bacterial meningitis. What is the MOST important
pathogenic component they share?
A. Protein A
B. *Capsule
C. Endotoxin
D. p-Lactamase
E. All are true
725.
Each of the following statements concerning Chlamydia trachomatis is correct EXCEPT:
A. It is an important cause of nongonococcal urethritis
B. It is the cause of lymphogranuloma venereum
C. *t is an important cause of subacute bacterial endocarditis
D. It is an important cause of conjunctivitis
E. All are true
726.
Which one of the following types of organisms is NOT an obligate intracellular parasite and
therefore can replicate on bacteriologic media?
A. Chlamydia
B. *Mycoplasma
C. Adenovirus
D. Rickettsia
E. All are true
727.
Tissue-degrading enzymes play an important role in the pathogenesis of several bacteria. Which
one of the following is NOT involved in tissue or cell damage?
A. Lecithinase of Clostridium perfringens
B.
C.
D.
E.
Hyaluronidase of Streptococcus pyogenes
*M protein of Streptococcus pneumoniae
Leukocidinof Staphylococcus aureus
All are true
728.
The soil is the natural habitat for certain microorganisms of medical importance. Which one of
the following is LEAST likely to reside there?
A. Clostridium tetani
B. Mycobacterium intracellular
C. Bacillus anthracis
D. *Chlamydia trachomatis
E. All are true
729.
Of the organisms listed below, which one is the MOST frequent bacterial cause of pharyngitis?
A. Staphylococcus aureus
B. Streptococcus pneumoniae
C. *Streptococcus pyogenes
D. Neisseria meningitidis
E. All are true
730.
Which one of the following organisms causes diarrhea by producing an enterotoxin that activates
adenylate cyclase?
A. *Escherichia coli
B. Bacteroides fragilis
C. Staphylococcus aureus
D. Enterococcus faecalis
E. All are true
731.
Each of the following statements concerning Clostridium perfringens is correct EXCEPT:
A. It causes gas gangrene
B. It causes food poisoning
C. It produces an exotoxin that degrades lecithin and causes necrosis and hemolysis
D. *It is a gram-negative rod that does not ferment lactose
E. All are true
732.
Which one of the following organisms causes diarrhea by producing an enterotoxin that activates
adenylate cyclase?
A. *Escherichia coli
B. Bacteroides fragilis
C. Staphylococcus aureus
D. Enterococcus faecalis
E. All are true
733.
Each of the following statements concerning Clostridium perfringens is correct EXCEPT:
A. It causes gas gangrene
B. It causes food poisoning
C. It produces an exotoxin that degrades lecithin and causes necrosis and hemolysis
D. *It is a gram-negative rod that does not ferment lactose
E. All are true
734.
Each of the following statements concerning Neisseria meningitidis is correct EXCEPT:
A. It is an oxidase-positive, gram-negative diplo-coccus
B. It contains endotoxin in its cell wall
C. *It produces an exotoxin that stimulates adenylate cyclase
D. It has a polysaccharide capsule that is antiphagocytic
E. All are true
735.
Resident flora can be found in all of the following locations in the human body EXCEPT the:
A. eye
B. skin
C. *blood
D. mouth
E. large intestine
736.
In which of the following anatomical locations would you expect to find the largest microbial
population?
A.
B.
C.
D.
E.
mouth
skin
kidneys
*large intestine
upper respiratory tract
737.
Bacteremia is
A. disease associated with bacterial infections of the cerebrospinal fluid.
B. disease associated with bacterial infections of the lower respiratory tract.
C. *disease associated with bacterial infections of the bloodstream.
D. disease caused by ingestion of a bacterial toxin.
E. disease caused by Clostridium difficile and Candida albicans in the intestinal tract.
738.
A 35-year-old woman presents with a history of increasing respiratory distress and cough
productive of sputum. Chest X-ray shows evidence of bilateral pneumonia. Cultures of blood and
sputum on Chocolate agar grow out slender Gram-negative rods; cultures on standard sheep blood agar
are negative. Which bacterium is most likely to be the cause of her infection?
A. Mycoplasma pneumoniae.
B. Chlamydia pneumoniae.
C. *Haemophilus influenzae.
D. Escherichia coli.
E. Streptococcus pneumonia
739.
A lactose-fermenting Gram-negative rod is isolated from the bloody stool of a young child.
Which pathogen is most likely?
A. Salmonella enterica.
B. *Escherichia coli.
C. Vibrio cholerae.
D. Shigella dysenteriae.
E. Clostridium difficile.
740.
A 15-year-old female presented with a three-day history of fever, headache and a non-productive
cough. Penicillin was prescribed and the patient was sent home. Her illness did not respond to this
antibiotic. Gram stain and culture of the patient's sputum and a throat swab revealed only 'normal oral
flora'. She was then successfully treated with erythromycin. Which organism below is most likely to
have caused her illness?
A. *Mycoplasma pneumoniae.
B. Haemophilus influenzae.
C. Mycobacterium tuberculosis.
D. Corynebacterium diphtheriae.
E. Streptococcus pneumoniae.
741.
Which organism below, if present in only one of three blood cultures from a single patient, is
most likely to represent contamination caused by poor antiseptic technique, rather than genuine
infection?
A. *Staphylococcus epidermidis.
B. Streptococcus pneumoniae.
C. Escherichia coli.
D. Pseudomonas aeruginosa.
E. Haemophilus influenzae.
742.
Which of the following bacteria can be successfully cultured on cell-free medium?
A. Chlamydia trachomatis.
B. Coxiella burnetii.
C. Mycobacterium leprae.
D. *Mycoplasma pneumoniae.
E. Rickettsia prowazekii.
743.
An 81-year-old man with chronic emphysemea and hypertension develops fever, chills, and
respiratory distress. X-rays show lobar pneumonia. Sputum smear contains numerous Gram-positive
cocci, many of which are in pairs. Sputum culture on Sheep blood agar produces many colonies of an
alpha-hemolytic Gram-positive coccus. It is catalase-negative, Bile-esculin negative, and optochinsensitive. Which of the organisms below is most likely?
A. Streptococcus pyogenes (Group A)
B.
C.
D.
E.
Streptococcus agalactiae (Group B)
Streptococcus mitis
Streptococcus bovis (Group D)
*Streptococcus pneumoniae
744.
A post-surgical patient develops redness around the incision and a day later pus begins to ooze
from the wound. Culture of a swab of pus produces beta-hemolytic colonies on Sheep blood agar. Gram
stain shows that the bacteria are Gram-positive cocci. Catalase and coagulase tests are positive. Which
of the following organisms is most likely?
A. Streptococcus pyogenes
B. Streptococcus agalactiae
C. Streptococcus mitis
D. *Staphylococcus aureus
E. Staphylococcus epidermidis
745.
A young woman develops urgency, frequency, and dysuria. Two days later she develops fever,
chills, and costovertebral angle tenderness. Tests of urine for leukocyte esterase and nitrate reductase are
positive. Urine culture yields a beta-hemolytic Gram-negative rod which forms dark-pink colonies on
MacConkey agar. Which of the following organisms is most likely?
A. Pseudomonas aeruginosa
B. Klebsiellla pneumoniae
C. *Escherichia coli
D. Staphylococcus saprophyticus
E. Enterobacter, sp.
746.
A vacationer develops watery diarrhea but not chills or fever. In this setting which of the
following pathogens is the most common?
A. Salmonella enterica
B. *Escherichia coli
C. Staphylococcus aureus
D. Campylobacter jejuni
E. Helicobacter pylori
747.
A child develops a "cold" which progresses to severe pharyngitis. Pharyngeal exudate forms a
tough 'membrane', difficult to remove without causing bleeding. Culture of a throat swab on selective
tellurite agar produces abundant black colonies. Other cultures produce only normal flora. Which
organism below is most likely to have caused this infection?
A. Streptococcus pneumoniae.
B. Haemophilus influenzae.
C. *Corynebacterium diphtheriae.
D. Bordetella pertussis.
E. Mycobacterium avium/intracellulare.
748.
A burn patient develops infection of the burn wound. Culture of exudate on Brain-Heart Infusion
agar produces numerous green-pigmented colonies of a Gram-negative rod. The organism grows well
aerobically on standard media but shows no evidence of acid production on differential media such as
MacConkey, Hektoen Enteric, or Triple-Sugar-Iron agars.
749.
What is the most likely organism?
A. Bacteroides fragilis
B. Campylobacter fetus
C. Francisella tularensis
D. *Pseudomonas aeruginosa
E. Escherichia coli
750.
A 19-year-old man comes to your clinic because of thick purulent discharge from the urethral
opening of his penis. On Gram-stain of the discharge huge numbers of neutrophils are seen, a few of
which contain intracellular Gram-negative cocci. Many of the cocci are in pairs. What is the most likely
organism?
A. Neisseria meningitidis.
B. *Neisseria gonorrhoeae.
C. Haemophilus ducreyi.
D. Mycoplasma hominis.
E. Treponema pallidum
751.
An elderly man develops pneumonia and septicemia. Gram stain of sputum contains many
neutrophils and Gram-positive cocci, in pairs. Blood and sputum cultures grow out a Gram-positive
coccus, alpha-hemolytic on sheep blood agar, and catalase-negative. Which organism below is most
likely?
A. Staphylococcus epidermidis
B. Staphylococcus aureus
C. *Streptococcus pneumoniae
D. Streptococcus pyogenes
E. Streptococcus agalactiae
752.
Infections with Staphylococcus aureus are on average more severe than infections with other
Staphylococci. What test result distinguishes S. aureus from other members of this genus?
A. Blackening of a bile-esculin slant.
B. *Coagulation of citrate-treated plasma.
C. Beta-hemolysis on sheep blood agar.
D. Blackening of an oxidase-test disc placed on a colony.
E. Resistance to bacitracin.
753.
Staphylococcus aureus is easily transmitted within the hospital environment. Which feature of
this bacterium is most largely responsible for its ease of spread?
A. *Resistance to heat, cold, and drying.
B. Ability to colonize the digestive tract.
C. Presence of an outer membrane impermeable to most disinfectants.
D. Production of extracellular polysaccharide which allows bacteria to adhere tightly to surfaces.
E. Formation of spores which are resistant to disinfectants and easily dispersed.
754.
A beta-hemolytic streptococcus is isolated from an infected neonate. Such isolates are often
members of Lancefield Group B. The antigenic structure of which bacterial component defines
Lancefield Groups?
A. Capsule polysaccharide.
B. *Cell-associated or C-carbohydrate.
C. Wall and membrane teichoic acids.
D. Beta-hemolysins.
E. Filamentous proteins of the cell envelope.
755.
A post-surgical patient develops fever and there is redness and swelling around the surgical
incision. A day later pus begins to flow from the incision; Gram stain of pus shows large numbers of
neutrophils and many Gram-positive cocci, some in clusters. The organism is beta-hemolytic on blood
agar, and is coagulase- and catalase-positive. Which organism is most likely?
A. *Staphylococcus aureus
B. Staphylococcus epidermidis
C. Streptococcus pyogenes (Group A)
D. Streptococcus agalactiae (Group B)
E. Streptococcus pneumoniae
756.
A patient presented with upper back pain. MRI imaging demonstrated inflammation of the T8T9 vertebral bodies consistent with osteomyelitis. A bone marrow biopsy, when cultured, produced
colonies of Gram-positive cocci.Colonies on Sheep blood agar were 3-4 mm in diameter, off-white and
beta-hemolytic. Colonies on Brain-heart infusion (BHI) agar were 2-3 mm in diameter and goldenyellow. Catalase and coagulase tests were positive. What was the most likely pathogen?
A. *Staphylococcus aureus
B. Staphylococcus epidermidis
C. Streptococcus pyogenes
D. Streptococcus pneumoniae
E. Streptococcus mitis
757.
A 20-year-old women presents at a local clinic with fever and abdominal tenderness. She reports
having had unprotected sexual intercourse a few weeks earlier. Gram-negative diplococci are seen in a
Gram stain of vaginal secretions; many of the bacteria are inside polymorphonuclear leukocytes. Which
virulence factor is most important in aiding this bacterium to initiate infection?
A. Ability to invade cells.
B. *Adhesive pili.
C. Anti-phagocytic capsule.
D. Endotoxin.
E. Flagella.
758.
Heavily-encapsulated strains of Neisseria meningitidis are far more virulent than nonencapsulated isolates. How does a capsule enhance virulence?
A. Binds to the Fc region of some subclasses of human IgG.
B. Prevents activation of complement by the classical pathway.
C. Enables bacteria to adhere tightly to mammalian cells.
D. Reduces access of antibiotics to the bacterial membrane.
E. *Inhibits phagocytosis by neutrophils
759.
Before the advent of immunization, outbreaks of meningococcal disease were frequent in
military camps. A factor in development of such outbreaks is the ability of Neisseria meningitidis to
establish an asymptomatic 'carrier state'. What is the predominant site of carriage of meningococci?
A. Urethral epithelium.
B. Gall bladder.
C. *Nasopharynx.
D. Large intestine.
E. Meninges and choroid plexus.
760.
A 23-year-old medical student had headache and fever one evening. By the next morning she had
become very ill, with high fever, severe headache, and stiff neck. She was admitted to the hospital. Later
that day she developed rash, first petechial and then pupuric. Her white count was 26,000/ull, with 80%
neutrophils and 10% 'bands'. Gram stain ofCSF showed many white cells and numerous bacteria. If the
pathogen is Neisseria meningitidis, how would you expect it to appear on Gram stain?
A. Gram-positive cocci, many in pairs.
B. Gram-positive cocci, many in clusters.
C. Isolated Gram-positive cocci.
D. *Gram-negative cocci, many in pairs.
E. Gram-negative cocci, many in clusters.
761.
A stool sample is plated on standard MacConkey-agar plates. After overnight incubation some of
the colonies are dark pink in color, others are pale, nearly colorless. What can you conclude about the
bacteria that produced dark- pink colonies?
A. Gram-positive.
B. *Ferment lactose.
C. Not likely to be 'normal flora'.
D. Non-motile.
E. Produce capsules.
762.
A strain of bacteria produced colorless colonies when cultured on standard MacConkey agar. It
was then used to inoculate a Sugar-Iron Agar slant. After overnight incubation, the tube was entirely
yellow and there were numerous bubbles inside the agar. There is no black precipitate. Which of the
following descriptions most accurately describes the metabolic reasons for these observations?
A. Produces H2S and gas
B. Ferments lactose and produces gas
C. *Ferments sucrose and produces gas.
D. Ferments neither lactose nor sucrose
E. Ferments glucose only
763.
A vacationing couple both develop severe watery diarrhea which lasts three days. Which
organism is the most common etiologic agent of such infections?
A. Shigella sonnei.
B. Pseudomonas aeruginosa.
C. Salmonella typhi.
D. Campylobacter jejuni.
E. *Escherichia coli.
764.
Several medical students go to Cancun over spring break. One evening, at a local bar, they drink
several pitchers of Margaritas made with crushed ice. They spend the next two days in their hotel room
with severe watery diarrhea, but no chills or fever. By the third day they recover completely. Which
organism is most likely to have been the cause of their illness?
A. Non-typhoidal Salmonella.
B. Helicobacter pylori.
C. Campylobacter jejuni.
D. *Enterotoxigenic E. coli.
E. Non-cholera Vibrio.
765.
A sexually-active woman develops a urinary tract infection which ascends to the kidneys
(pyelonephritis). Blood culture yields a beta-hemolytic Gram-negative rod. In this situation, which
pathogen below is most common?
A. Salmonella enteritidis.
B. Pseudomonas aeruginosa.
C. Serratia marcescens.
D. Klebsiella pneumoniae.
E. *Escherichia coli.
766.
23-year-old woman comes to your office because, for 3 days, she has experienced burning with
urination, increased frequency of urination, and a continual feeling that she needs to urinate. She does
not have vaginal discharge, fever, or flank pain. Rapid 'dipstick' urine tests are consistent with
uncomplicated cystitis. Culture of urine on standard media produces a lactose-fermenting Gramnegative rod. In situations such as this, what is the most likely pathogen?
A. Enterobacter faecium
B. *Escherichia coli
C. Klebsiella pneumoniae
D. Proteus vulgaris
E. Pseudomonas aeruginosa
767.
Which phrase best describes typical infections by Campylobacter jejuni?
A. Non-inflammatory enteritis
B. *Inflammatory enteritis
C. Systemic infection
D. Urinary tract infection
E. Meningitis
768.
A patient has chronic gastritis. Which of the following organisms is most likely?
A. Campylobacter fetus.
B. Campylobacter jejuni.
C. *Helicobacter pylori.
D. Escherichia coli.
E. A non-cholera Vibrio.
769.
Gastroscopy reveals that a patient with stomach pain has a large ulceration of his gastric mucosa.
During the procedure a biopsy of the stomach epithelium is obtained.
770.
Which observation would suggest Helicobacter pylori as the cause of illness?
A. *Curved or spiral bacteria are seen in the biopsy after silver staining.
B. Biopsy shows infiltration of gastric epithelium by lymphocytes.
C. pH of stomach fluid is equal to 1 (normal), rather than decreased.
D. Ingested isotope-labeled nitrate is converted to nitrite in the stomach.
E. Bacteria are found in stomach fluid, but not in contact with the gastric epithelium
771.
A child has Pertussis. How was this infection most likely to have been acquired?
A. Release of oral flora into the bloodstream by dental work.
B. Bite of a dog or cat.
C. Contact with livestock, or animal products such as leather or wool.
D. Consumption of dairy products made from unpasteurized milk
E. *Inhalation of respiratory droplets from another person.
772.
A patient is diagnosed with Clostridium difficile colitis. Which item would represent a known
risk factor for such infections?
A. *Been treated with antibiotics.
B. Consumed unpurified water.
C. Visited the southwestern United States.
D. Eaten undercooked fried rice.
E. Been in contact with livestock
773.
A 22-year-old develops an abscess in his peritoneum following rupture of his appendix. Gram
stain of exudate from his foul-smelling abscess reveals numerous polymorphonuclear leukocytes, Grampositive cocci, Gram-positive rods, and Gram-negative rods. Aerobic culture of the exudate at 37oC on
blood and MacConkey agar yields only Enterococci.Which of the bacteria below is most likely to be the
Gram-negative rods seen in the stained smear?
A. Pseudomonas aeruginosa.
B. Proteus mirabilis.
C. Klebsiella pneumoniae.
D. Prevotella melaninogenica.
E. *Bacteroides fragilis.
774.
The young man was injuring in car accident. The affected area of the leg is painful, red, and
swollen. During the next 12 hours the swelling increases markedly, the skin of the leg becomes
discolored, and fluid-filled blisters appear on the skin. Gram stain of fluid aspirated from a blister
reveals large Gram-positive rods. Which organism below is most likely to have caused this infection?
A. Clostridium botulinum.
B. *Clostridium perfringens.
C. Clostridium difficile.
D. Clostridium tetani.
E. Listeria monocytogenes.
775.
A patient has endocarditis produced by an alpha-hemolytic Streptococcus. This usually reflects
spread of normal flora to the bloodstream. From which site is this isolate most likely to have spread?
A. Anterior nares.
B. Facial skin.
C. Lower respiratory tract.
D. Distal urethra.
E. *Oropharynx
776.
A five-day-old child develops high fever and stiff neck. A spinal tap is performed. A Gramstained smear of cerebrospinal fluid reveals many neutrophils and short, thick, Gram-negative rods of
uniform length. This microbes can ferment lactose.Which organism below is most likely to have caused
this infection?
A. *Escherichia coli
B. Haemophilus influenzae
C. Streptococcus pneumoniae
D. Neisseria meningitidis
E. Streptococcus agalactiae
777.
A nine years-old child develops high fever and stiff neck. A spinal tap is performed. A Gramstained smear of cerebrospinal fluid reveals many neutrophils and Gram-negative cocci that resemble
paired kidney beans within leucocytes. Which organism below is most likely to have caused this
infection?
A. Escherichia coli
B. Haemophilus influenzae
C. Listeria monocytogenes
D. *Neisseria meningitidis
E. Streptococcus agalactiae
778.
Gram stain of CSF sediment from a patient with meningitis contains Gram-negative cocci, many
in pairs. Which organism below is most likely?
A. Streptococcus pneumoniae
B. Haemophilus influenzae
C. *Neisseria meningitidis
D. Pseudomonas aeruginosa
E. Escherichia coli
779.
Which test below would best distinguish S. aureus from one of the less-virulent staphylococci?
A. Production of catalase.
B. Colony color when grown on BHI agar.
C. Ability to grow on MacConkey agar.
D. *Production of coagulase.
E. Type of hemolysis on sheep blood agar.
780.
The laboratory informs you that an isolate of Staphylococcus aureus is ‘methicillin-resistant’.
Which phrase below best describes such isolates?
A. Although resistant to methicillin, nearly all are sensitive to cephalosporins.
*They are resistant to both ‘anti-staph’ penicillins and cephalosporins.
They are seldom resistant to antibiotics other than ?-lactams.
They produce a ?-lactamase active on both cephalosporins and penicillins.
The ‘methicillin-resistance’ gene also confers resistance to vancomycin.
781.
A young man has a large pus-filled abscess on his upper arm but does not go to a doctor. Several
days later he is brought to the Emergency Room with fever, hypotension, and multiple organ failure.
Which of the following is most likely to be responsible?
A. Streptococcus pyogenes Erythrogenic toxin.
B. Clostridium perfringens ?-toxin.
C. *Staphylococcus aureus Toxic Shock Syndrome Toxin-1.
D. Shigella dysenteriae Shiga Toxin.
E. Escherichia coli Heat-labile Toxin (ST).
782.
Members of a family suffer acute attacks of nausea and vomiting a few hours after returning
from a daylong picnic, at which they ate hamburgers, potato salad, and custard pie. By morning all are
feeling better. Which bacterial toxin is most likely to have caused their symptoms?
A. Clostridium difficile Cytotoxin.
B. Escherichia coli Labile Toxin
C. Escherichia coli Stable Toxin.
D. *Staphylococcus aureus Enterotoxin.
E. Helicobacteri pylori Cytotoxin.
783.
A patient with Cystic fibrosis develops pneumonia. A Gram-negative rod is cultured from her
respiratory tract. On nutrient-poor media it grows well and secretes large amounts of bright green
pigment. It produces acid from none of the sugars on which it was tested (including lactose and
sucrose). Which organism below is most likely?
A. Shigella sonnei
B. Salmonella typhi
C. *Pseudomonas aeruginosa
D. Escherichia coli
E. Klebsiella pneumoniae
784.
Bacteroides fragilis is isolated from an abdominal abscess. Which phrase below best describes
infections like this one?
A. *Other species of bacteria are also often present.
B. Initiated by ingestion of spores.
C. Can be successfully treated with aminoglycosides alone.
D. Contracted by the respiratory route.
E. Sexually-transmitted
785.
A young woman has a urinary tract infection caused by E. coli. By what route are such infections
most commonly acquired?
A. Respiratory route, followed by spread from the anterior nares.
B. Respiratory route, followed by spread from the oro-pharyngeal region.
C. *Fecal-oral route, followed by colonization of the intestine and then the perineum.
D. Intestinal infection, followed by spread of bacteria to the urethra via the bloodstream.
E. Direct contact route
786.
What is the most common outcome of infection with Helicobacter pylori?
A. Severe diarrhea
B. No clinical manifestations
C. Bacteremia
D. Hepatitis
E. *Peptic ulcers or gastric cancer
787.
A 35-year old patient got fever, nausea, vomiting and bloody diarrhea, all of the following
bacteria should be considered in the diffrential diagnosis, except one:
A. Salmonella
B. ETEC
C. Shigella
D. Yersinia
E. *Campylobacter
788.
A 38 years old patient has chronic gastritis. Which of the following organisms is most likely?
B.
C.
D.
E.
A.
B.
C.
D.
E.
Campylobacter fetus.
Escherichia coli.
A non-cholera Vibrio.
Campylobacter jejuni.
*Helicobacter pylori.
A 40-years-old patient has a peptic ulcer. Which organism is most likely to have created this
789.
lesion?
A. Campylobacter jejuni.
B. Enterococcus faecalis.
C. Escherichia coli.
D. Salmonella enteritidis
E. *Helicobacter pylori
790.
A 5-years-old girl develops bloody diarrhea, produced by Shigella infection. From which source
was this infection most likely to have been contracted?
A. Rare hamburger.
B. Dog or cat.
C. Spores present in soil.
D. Cow, horse, or sheep.
E. *Another child.
791.
A 6-year-old boy was brought to the emergency room with a history of bloody diarrhea over the
preceding two days. A fecal smear contained numerous red cells and neutrophils. Stool culture on Endo
agar produced lactose-negative colonies amid colonies of ‘normal intestinal flora’. Which of the
organisms below is most likely to be the cause of his illness?
A. Enteropathogenic E. coli
B. Balantidium coli.
C. Entamoeba histolytica
D. Giardia lamblia.
E. *Shigella.
792.
A few healthy adult travelers visiting Peru are cautioned against eating uncooked vegetables and
unpeeled fruits, and against drinking unbottled water. However, they are already resistant to cholera
because of:
A. the gamma globulin shots they received before their trip.
B. their ability to avoid contaminated food due to its acidic smell.
C. they were vaccinated
D. their consumption of large prophylactic amounts of bicarbonates.
E. *a gastric barrier, due to stomach acids.
793.
A four-year-old boy was brought to the emergency room with a history of bloody diarrhea over
the preceding two days. A fecal smear contained numerous red cells and neutrophils. Stool culture on
Endo agar produced lactose-negative colonies amid colonies of ‘normal intestinal flora’. Which of the
organisms below is most likely to be the cause of his illness?
A. Enteropathogenic E. coli
B. Balantidium coli.
C. Entamoeba histolytica
D. D.Giardia lamblia.
E. *Shigella.
794.
A four-year-old boy was brought to the emergency room with a history of bloody diarrhea over
the preceding two days. A fecal smear contained numerous red cells and neutrophils. Stool culture on
Endo agar produced lactose-negative colonies amid colonies of ‘normal intestinal flora’. Which of the
organisms below is most likely to be the cause of his illness?
A. Enteropathogenic E. coli
B. Balantidium coli.
C. Entamoeba histolytica
D. Giardia lamblia.
E. *Shigella.
795.
A laboratory got a sample from a patient with cholera. Which of the following tests would not
differentiate Vibrio cholera non O1 from Vibrio parahaemolyticus?
A. oxidase activity.
B.
C.
D.
E.
Growth on special blood agar
Production of enterotoxin
Growth on salt-free and salt-containing agar.
*Growth on TCBS agar
796.
A laboratory got a sample from a patient with cholera. Which of the following is not true about
the bacterium classified as Vibrio cholerae (V. cholerae О1):
A. causes disease only through the production of an enterotoxin
B. reacts with group 1 antiserum against the lipopolysaccharide (О) antigens
C. arabinose is not fermented
D. invades the small intestine
E. *is often associated with marine environments
797.
A laboratory got a sample from a patient with diarrhoea. Which of the following media is an
enrichment medium for the isolation of Shigella?
A. Tetrathionate broth.
B. Alkaline peptone water.
C. Taurocholate peptone transport and enrichment medium.
D. Endo medium
E. *Selenite F broth.
798.
A laboratory got a sample from a patient with diarrhoea. Cholera toxin resembles which of the
following toxins?
A. Stable toxin of E. coli.
B. Diphtheria toxin.
C. Tetanus toxin.
D. Staphylococcus enterotoxin
E. *Labile toxin of Escherichia coli.
799.
A laboratory got a sample from a patient with diarrhoea. To test a stool specimen for
Campylobacter, all of the following measures would be used except:
A. Plating on agar containing glucose or sucrose
B. Plating on Campy blood agar containing 5 antibiotics
C. Incubating the plates in an atmosphere of 5% O2, 10% CO2
D. Incubating the plates at 42° C
E. *Passing the samples through 0.45 micron filters
800.
A laboratory got a sample from a patient with diarrhoea. Shigella is transmitted by
A. ticks
B. direct contact
C. air dropled
D. louse
E. *infected food and water
801.
A laboratory got a sample from a patient with diarrhea. The severe diarrhea of cholera is
produced by a protein exotoxin that acts on enterocytes. Which statement below best describes the effect
of Cholera toxin?
A. Alters the actin cytoskeleton.
B. Inactivates ribosomes.
C. Stimulates guanyl cyclase.
D. Proteolytic cleavage of a specific cellular protein.
E. *Stimulates adenyl cyclase.
802.
A laboratory got a specimen from a patient with cholera. The following occurs during the course
of disease due to Vibrio cholerae infection, except one:
A. Patients experience nausea, vomiting, abdominal cramping, and diarrhea.
B. Patients sometimes lose between 10 to 20 liters of fluid/day.
C. “Rice-water” stool presents
D. Patients show signs of disease at 8 to 72 hrs after ingestion of contaminated food or water.
E. *Patients sustain considerable damage to their intestines.
803.
A man, 38 y.o. has gastritis. The pathogenic mechanisms that make Helicobacter pylori the
causative agent of gastritis include the following except:
A. urease production
B. catalase production
C. microaerophilism
D. motility
E. *invasive abilities
804.
A microbiologist got a sample from a patient with cholera. Which of the following statements is
true about the toxin produced by Vibrio cholera?
A. The B subunit directly stimulates the host adenylate cyclase.
B. The toxin blocks the host adenylate cyclase.
C. The toxin is lypopolisaccharide
D. It has its own adenylate cyclase activity.
E. *The A1 subunit indirectly stimulates the host adenylate cyclase.
805.
A microbiologist got a specimen from a patient with cholera. To determine to which species of
vibrios infectious agent belongs, the microbiologist performs some tests on colonies cultured from stool
samples. These tests include the following EXCEPT:
A. growth on thiosulfate-citrate-bile-sucrose (TCBS) agar
B. fermentation of sucrose
C. phagotyping
D. growth at different NaCl concentrations
E. *serotyping based on H antigens
806.
A middle aged man recently returned from visiting his family in India develops severe diarrhea.
He in fact has cholera. His diarrhea is produced by a protein exotoxin secreted by Vibrio cholerae. How
does this toxin act?
A. ADP-ribosylates a chloride transporter.
B. Stimulates guanyl cyclase.
C. Inhibits guanyl cyclase.
D. Inhibits a G protein that inhibits adenyl cyclase.
E. *Stimulates a G protein that activates adenyl cyclase.
807.
A motive not to administer beta lactam antibiotics for a Gram-negative septicemia, unless there
is no other alternative, is
A. the lysis of bacterial cells increases the activity of bacterial LPS
B. Complement activation cannot occur in the presence of the antibiotic
C. the antibiotic suppresses the immune response necessary to eliminate the pathogen
D. the antibiotic eliminates the normal flora
E. *beta lactam antibiotics are ineffective against Gram-negative bacteria
808.
A patient got diarrhoea. The pathogenesis of which one of the following organisms is MOST
likely to involve invasion of the intestinal mucosa?
A. Enterotoxigenic Escherichia coli
B. Clostridium botulinum
C. Enteropathogenic Escherichia coli
D. Vibrio cholerae
E. *Shigella sonnei
809.
A patient got severe diarrhoea. If this patient had Shigellosis, the stool culture on MacConkey
agar will grow:
A. glucose fermenting colonies
B. pink colonies
C. black colonies
D. lactose fermenting colonies
E. *non-lactose fermenting colonies
810.
A patient has a peptic ulcer. Which organism is most likely to have created this lesion?
A. Campylobacter jejuni.
B. Enterococcus faecalis.
C. Salmonella enteritidis
D. Escherichia coli.
E. *Helicobacter pylori
811.
A patient has been diagnosed with a gastric ulcer. A test of the patient's serum shows reactivity
with Helicobacter pylori antigens. Which of the following is true?
A. The patient's gastrin-hydrochloric homeostasis has been maintained.
B. Damage to the patient's gastric mucosa has been primarily caused by the patient's own immune
response.
C. All are true
D. The Helicobacter pylori infection most likely has nothing to do with the patient's condition.
E. *The patient will be treated with amoxicillin to eradicate H. pylori colonization and eliminate its
recurrence.
812.
A patient has chronic gastritis. Which of the following organisms is most likely?
A. Escherichia coli.
B. A non-cholera Vibrio.
C. Campylobacter fetus.
D. Campylobacter jejuni.
E. *Helicobacter pylori.
813.
A person got cholera. The best treatment for cholera is
A. tetracycline
B. toxoid
C. vaccine
D. antiserum injection
E. *rehydration therapy
814.
A person got cholera. The large volume of fluid lost by diarrhea during infection with Vibrio
cholerae
A. is a consequence of fluid replacement during treatment of the disease and does not result directly
from activity of the cholera toxin
B. results from electrolytes binding to the intestinal enterocytes which upsets their water retention
capability
C. results from neurotoxic effects of the cholera toxin on the central nervous system
D. is caused when the vibrios bind to the intestinal epithelium and physically or mechanically block
the uptake of fluids by the gut epithelial cells
E. *follows activation of adenylate cyclase by cholera toxin and the subsequent effect of cyclic
AMP on water and salt balances of the host cells
815.
A person got cholera. What is the incubation period for cholerae?
A. 6 to 8 hours
B. 2 to 4 days
C. 1 to 2 weeks
D. 12 to 24 hours
E. *48 to 72 hours
816.
A stool sample is plated on standard Endo-agar plates. After overnight incubation some of the
colonies are dark pink in color, others are pale, nearly colorless. What can you conclude about the
bacteria that produced dark-pink colonies?
A. Not likely to be ‘normal flora’.
B. Non-motile.
C. Produce capsules
D. Gram-positive.
E. *Ferment lactose.
817.
A test of the patient's serum shows reactivity with Helicobacter pylori antigens. Which of the
following is true?
A. The patient's gastrin-hydrochloric homeostasis has been maintained.
B. Damage to the patient's gastric mucosa has been primarily caused by the patient's own immune
response.
C. All are true
D. The Helicobacter pylori infection most likely has nothing to do with the patient's condition.
E. *The patient will be treated with amoxicillin to eradicate H. pylori colonization and eliminate its
recurrence.
818.
A urease-positive, spiral-shaped gram-negative rod is found in gastric washings from a 29-yearold stressed-out medical student with gastritis. Which of the following is most likely tobe this organism?
A. Proteus mirabilis
B. Providencia rettgeri
C. Vibrio cholerae
D. Campylobacter jejuni
E. *Helicobacter pylori
819.
A young child develops bloody diarrhea, produced by Shigella infection. From which source
was this infection most likely to have been contracted?
A. Rare hamburger.
B. Spores present in soil.
C. Dog or cat.
D. Cow, horse, or sheep.
E. *Another child.
820.
A young man got a dysentery. Which Escherichia coli type is most like Shigella in its virulence
plasmid and mode of infection:
A. EHEC
B. EPEC
C. EAggEC
D. ETEC
E. *EIEC
821.
A young man got a dysentery. Which of the following is not true about Shigella?
A. Causes bacillary dysentery
B. Most strains are lactose nonfermenters
C. Virulence is plasmid mediated
D. The organism multiplies directly in the host cell
E. *Serotyping is based on O and H antigens
822.
A young woman got a dysentery. Humans acquire shigellosis from:
A. dogs
B. cats
C. swine
D. chickens
E. *humans
823.
A young woman got cholera. The hallmark of therapy for severe cases of cholera is:
A. antimicrobial therapy
B. outpatient treatment
C. serotherapy
D. vaccination
E. *replacement of electrolytes
824.
A young woman got cholera. To determine to which species the infectious agent belongs, the
microbiologist performs some tests on colonies cultured from stool samples. These tests include the
following EXCEPT:
A. growth on thiosulfate-citrate-bile-sucrose (TCBS) agar
B. serotyping based on O antigens
C. fermentation of sucrose
D. growth at different NaCl concentrations
E. *serotyping based on H antigens
825.
Among the Sunday night patients at the Smithville emergency room were ten young adults
suffering from severe diarrhea. All of these individuals would normally characterize themselves as
being in good health. All reported eating at a local Dairy fair during the weekend. Of the following
bacterial species the least likely to be responsible is
A. Campylobacter fetus
B. Shigella flexneri
C. Campylobacter jejuni
D. Yersina enterocolitica
E. *Salmonella typhimurium
826.
An engineer recently returned from visiting his family in India develops severe diarrhea. He in
fact has cholera. His diarrhea is produced by a protein exotoxin secreted by Vibrio cholerae. How does
this toxin act?
A. Stimulates guanyl cyclase.
B. Inhibits guanyl cyclase.
C. ADP-ribosylates a chloride transporter.
D. Inhibits a G protein that inhibits adenyl cyclase.
E. *Stimulates a G protein that activates adenyl cyclase.
827.
Both the E. coli LT toxin and the cholera toxin
A. have an A+B subunit arrangement
B. are identical in their primary structure
C. are ADP-ribosylating toxins
D. have an enzymatic mechanism of action
E. *all answers are correct
828.
By which of the following methods Helicobacter pylori, a cause of peptic ulcers and gastric
carcinoma, is diagnosed?
A. Serology (serum) test
B. Biopsy (invasive)
C. Radioactive isotope C14 test
D. All answers are correct
E. *Bacteriological method
829.
During the procedure a biopsy of the stomach epithelium is obtained. Which observation would
suggest Helicobacter pylori as the cause of illness?
A. Biopsy shows infiltration of gastric epithelium by lymphocytes.
B. pH of stomach fluid is equal to 1 (normal), rather than decreased.
C. Ingested isotope-labeled nitrate is converted to nitrite in the stomach.
D. Bacteria are found in stomach fluid, but not in contact with the gastric epithelium
E. *Curved or spiral bacteria are seen in the biopsy after silver staining.
830.
From a 29-year-old stressed-out medical student with gastritis a urease-positive, spiral-shaped
gram-negative rod is found in gastric washings. Which of the following is most likely to be this
organism?
A. Proteus mirabilis
B. Providencia rettgeri
C. Vibrio cholerae
D. Campylobacter jejuni
E. *Helicobacter pylori
831.
Gastroenteritis caused by Campylobacter jejuni is associated with consumption of contaminated
water or foods which include the following EXCEPT:
A. milk
B. poultry
C. chicken
D. clams
E. *hamburger
832.
Gastroscopy reveals that a patient with stomach pain has a large ulceration of his gastric mucosa.
During the procedure a biopsy of the stomach epithelium is obtained. Which observation would suggest
Helicobacter pylori as the cause of illness?
A. Biopsy shows infiltration of gastric epithelium by lymphocytes.
B. pH of stomach fluid is equal to 1 (normal), rather than decreased.
C. Ingested isotope-labeled nitrate is converted to nitrite in the stomach.
D. Bacteria are found in stomach fluid, but not in contact with the gastric epithelium
E. *Curved or spiral bacteria are seen in the biopsy after silver staining.
833.
Healthy adult travelers visiting Peru are cautioned against eating uncooked vegetables and
unpeeled fruits, and against drinking unbottled water. However, they are already resistant to cholera
because of:
A. the gamma globulin shots they received before their trip.
B. their ability to avoid contaminated food due to its acidic smell.
C. their consumption of large prophylactic amounts of bicarbonates.
D. they were vaccinated
E. *a gastric barrier, due to stomach acids.
834.
If this patient had Shigellosis, the stool culture on MacConkey agar will grow:
A. glucose fermenting colonies
B. pink colonies
C. black colonies
D. lactose fermenting colonies
E. *non-lactose fermenting colonies
835.
In a 30-year old patient with fever, nausea, vomiting and bloody diarrhea, all of the following
bacteria should be considered in the diffrential diagnosis, except one:
A. Salmonella
B. Yersinia
C. ETEC
D. Shigella
E. *Campylobacter
836.
Outbreaks of diarrhea caused by species of Shigella are common in day-care centers for children
and other similar settings. What property of Shigella most enhances its spread between children?
A. Frequent presence in the upper respiratory tracts of children who are not ill
B. Ability to ferment lactose and grow in refrigerated milk.
C. Possession of an envelope resistant to disinfectants.
D. Carriage by common classroom pets such as hamsters and gerbils
E. *Resistance to stomach acid and low infectious dose.
837.
Salmonella, Yersinia, Escherichia and Shigella are put together in Bergey's Manual because they
are all
A. gram-positive aerobic cocci
B. fermentative
C. none answers are correct
D. pathogens
E. *gram-negative facultatively anaerobic rods
838.
The microbiologist is aware that the gastroenteritis outbreak is associated with the consumption
of raw seafood at a local restaurant. She considers it may be due to a number of vibrios EXCEPT:
A. V. parahaemolyticus
B. V. alginolyticus
C. V. vulnificus
D. V. cholerae non 01
E. *V. fluvialis
839.
The severe diarrhea of cholera is produced by a protein exotoxin that acts on enterocytes. Which
statement below best describes the effect of Cholera toxin?
A. Alters the actin cytoskeleton.
B. Stimulates guanyl cyclase.
C. Inactivates ribosomes.
D. Proteolytic cleavage of a specific cellular protein.
E. *Stimulates adenyl cyclase.
840.
Which following measures does not prevent Vibrio parahaemolyticus infections?
A. cook seafood for the appropriate time
B. proper refrigeration
C. vaccination
D. never return cooked seafood to the original container
E. *consume alcohol along with raw seafood
841.
Which microbe produce verotoxin?
A. S. dysenterie serotype 2
B. S. dysenterie serotype 4
C. S.dysenterie serotype 8
D. S.dysenterie serotype I0
E. *Shigella dysenterie serotype I
842.
Which one of the following organisms is MOST likely to involve invasion of the intestinal
mucosa?
A. Enterotoxigenic Escherichia coli
B. Clostridium botulinum
C. All answers are correct
D. Vibrio cholerae
E. *Shigella sonnei
843.
Young woman got cholera. Which of the following is the least accurate statement regarding
Vibrio cholerae?
A. Cholera toxin is closely related to E. coli LT (heat labile toxin).
B. Infected patients suffer from electrolyte deficiency and metabolic acidosis.
C. Fimbrial adhesions produced by the organism facilitate adherence to the brush border of
intestinal epithelial cells.
D. Can grow on alkalaine media
E. *Dark-field microscopic observation of stool from infected patients reveals large nonmotile rods.
844.
Your patient is a 30-year-old woman who was part of a tour group visiting a N. country. The day
before leaving, several members of the group developed fever, abdominal cramps, and bloody diarrhea.
Of the following, which one is the LEAST likely organism to cause this infection?
A. Salmonella enteritidis
B. Vibrio cholerae
C. Campylobacter jejuni
D. Staphylococcus aureus
E. *Shigella dysenteriae
845.
Your patient is a 30-year-old woman who was part of a tour group visiting a N. country. The day
before leaving, several members of the group developed fever, abdominal cramps, and bloody diarrhea.
Which of the following bacterium is causative agent of dysenteriae?
A. E. coli
B. Klebsiella
C. Proteus
D. Vibrio
E. *Shigella
846.
______ hemolysis is the partial lysis of red blood cells due to bacterial hemolysins.
A. Beta
B. Gamma
C. Delta
D. Epsilon
E. *Alpha
847.
The ___________ test is employed in chronic and complicated cases of gonorrhea:
A. Agglutination test
B. Precipitation test
C. Neutralisation test
D. RIHAT
E. *Bordeux-Gengou complement-fixation test
848.
_____ are surface appendages that allow a bacterium to stick to a surface.
A. Cell walls
B. Flagella
C. Ribosomes
D. Mitochondria
E. *Pili
849.
A characteristic of Streptococcus mutans that allows it to initiate dental plaque and dental caries
is:
A. the ability to attach specifically to the pellicle of the tooth
B. the ability to utilize sucrose as a source of carbon and energy
C. the ability to produce a dextran capsule
D. all are right
E. *the ability to produce lactic acid
850.
A complication of genital gonorrhea in both men and women is
A. pelvic inflammatory disease
B. arthritis
C. blindness
D. urethritis
E. *infertility
851.
A condition characterized by the multiplication of bacteria in blood.
A. bacteremia
B.
C.
D.
E.
bulimia
anemia
septicopiemia
*septicemia
852.
A genus of bacteria that are gram - positive organisms occurring in pairs. Also called
A. streptococcus.
B. diplobacilli
C. streptobacilli
D. coccus
E. *diplococcus
853.
A gram-positive cocci that occurs in chains.
A. staphylococcus
B. rickettsia
C. streptobacilli
D. Neisseria
E. *streptococci
854.
A positive Schick test implies that the person is:
A. immune and non-hypersensitive.
B. immune and hypersensitive.
C. non-immune and hypersensitive.
D. healthy
E. *susceptible and non-hypersensitive.
855.
A substance that destroys microorganisms has name
A. viricide
B. fungicide
C. germicide
D. multicide
E. *bactericide
856.
A type of bacteria that is spherical or ovoid in form.
A. bacillus
B. spirillum
C. spirochete
D. vibrio
E. *coccus
857.
What of the statements about the classification of streptococci is correct EXCEPT:
A. Pneumococci Streptococcus pneumoniae) are alpha-hemolytic and can be serotyped on the basis
of their polysaccharide capsules
B. Enterococci are group D streptococci and can be classified by their ability to grow in 6.5%
sodium chloride
C. Although pneumococci and the viridans streptococci are alpha-hemolytic, they can be
differentiated by the bile solubility test and their susceptibility to optochin
D. *Viridans streptococci are identified by Lance-field grouping, which is based on the C
carbohydrate in the cell wall
E. All are right
858.
Alpha-haemotoxin-producing streptococci are characterized by the appearance of _______
zones around the colonies:
A. Red
B. Brown
C. Colorless
D. No correct answer
E. *Green
859.
An effective vaccine exists to prevent infections from
A. Staphylococcus aureus
B. Streptococcus pyogenes
C. Neisseria gonorrhoeae
D. Streptococcus epidermidis
E. *Streptococcus pneumoniae
860.
An important test for identifying Neisseria is
A. production of catalase
B. sugar fermentation
C. beta-hemolysis
D. alfa- hemolysis
E. *production of oxidase
861.
Bacitracin sensitivity is used to distinguish
A. Streptococcus pneumoniae from other alpha-hemolytic streptococci.
B. Staphylococcus aureus from Staphylococcus epidermidis.
C. Staphylococcus from Micrococcus.
D. Group A Streptococcus. from Streptococcus pneumoniae.
E. *Group A Streptococcus from other beta-hemolytic streptococci.
862.
Beta-haemotoxin-producing streptococci are characterized by the appearance of _______ zones
around the colonies:
A. Red
B. Brown
C. Green
D. No correct answer
E. *Colorless
863.
Biochemical properties of Streptococci:
A. non-proteolytic
B. do not liquefy gelatin
C. do not reduce nitrates to nitrites
D. No correct answer
E. *All answers are correct
864.
Characteristics of Streptococcus mutans which allow it to initiate dental caries include
A. the ability to attach specifically to the pellicle of the tooth
B. the ability to form and grow in a biofilm on the enamel of the tooth
C. all are right
D. none of the above
E. *the ability to produce lactic acid from sucrose, glucose and fructose
865.
Choose faithful composition of yolk salt agar
A. MPA, sheep , 9 % of sodium chloride
B. MPA, rabbit red cells, 9 % of sodium chloride
C. MPA, horse red cells , 9 % of sodium chloride
D. MPA, glucose, 9 % chloride of sodium
E. *MPA, yolk, 9 % of sodium chloride
866.
Components of Bordeux – Gengou complement fixation test for diagnosis of gonorrhea:
A. Isotonic sodium chloride solution, discharges from urethra, gonococcal diagnosticum,
complement, hemolytic system (hemolytic serum and 3 % sheep erythrocytes suspension)
B. Isotonic sodium chloride solution, patient’s serum, gonococcal diagnosticum, complement,
hemolytic system (hemolytic serum)
C. Isotonic sodium chloride solution, patient’s serum, gonococcal diagnosticum, complement, and
3 % sheep erythrocytes suspension)
D. Isotonic sodium chloride solution, patient’s serum, complement, hemolytic system (hemolytic
serum and 3 % sheep erythrocytes suspension)
E. *Isotonic sodium chloride solution, patient’s serum, gonococcal diagnosticum, complement,
hemolytic system (hemolytic serum and 3 % sheep erythrocytes suspension)
867.
Condition of Meningococci cultivation for diagnosis of epidemic meningitis:
A. The inoculated culture is incubated at 22 °C and in conditions of elevated CO2 contents
B. The inoculated culture is incubated at 22 °C and in conditions of elevated O2 contents
C. The inoculated culture is incubated at 37 °C and in conditions of elevated O2 contents
D. The inoculated culture is incubated at 37 °C
E. *The inoculated culture is incubated at 37 °C and in conditions of elevated CO2 contents
868.
Each of the following agents is a recognized cause of diarrhea EXCEPT:
A. Clostridium perfringens
B. Escherichia coli
869.
870.
871.
872.
873.
874.
875.
876.
C. Vibrio cholerae
D. Rotavirus
E. *Enterococcus faecalis
Each of the following statements concerning gonorrhea is correct EXCEPT:
A. Infection in men is more frequently symptomatic tYan in women
B. A presumptive diagnosis can be made by finding gram-negative kidney-bean-shaped diplococci
within neutrophils in a urethral discharge
C. Gonococcal conjunctivitis of the newborn rarely occurs in the United States, because silver
nitrate or erythromycin is commonly used as prophylaxis
D. All are right
E. *The definitive diagnosis can be made by detecting at least a 4-fold rise in antibody to Neisseria
gonorrhoeae
Each of the following statements concerning neisseriae is correct EXCEPT:
A. They are gram-negative diplococci
B. They produce IgA protease as a virulence factor
C. They are oxidase-positive
D. All answers are right
E. *They grow best under anaerobic conditions
Each of the following statements concerning Neisseria meningitidis is correct EXCEPT:
A. It is an oxidase-positive, gram-negative diplo-coccus
B. It contains endotoxin in its cell wall
C. It has a polysaccharide capsule that is antiphagocytic
D. All are right
E. *It produces an exotoxin that stimulates adenylate cyclase
Each of the following statements concerning Staphylococcus aureus is correct EXCEPT:
A. Gram-positive cocci in grapelike clusters are seen on Gram-stained smear
B. The coagulase test is positive
C. Treatment should include a (3-lactamase-resistant penicillin
D. All answers are right
E. *Endotoxin is an important pathogenetic factor
Each of the following statements concerning staphylococci is correct EXCEPT:
A. S. aureus is differentiated from S. epidermidis by the production of coagulase
B. S. aureus infections are often associated with abscess formation
C. The majority of clinical isolates of S. aureus elaborate penicillinase; therefore, presumptive
antibiotic therapy for S. aureus infections should not consist of penicillin G
D. All answers are right
E. *Scalded skin syndrome caused by S. aureus is due to enzymatic degradation of epidermal
desmosomes by catalase
Each of the statements about the classification of streptococci is correct EXCEPT:
A. Pneumococci Streptococcus pneumoniae) are alpha-hemolytic and can be serotyped on the basis
of their polysaccharide capsules
B. Enterococci are group D streptococci and can be classified by their ability to grow in 6.5%
sodium chloride
C. Although pneumococci and the viridans streptococci are alpha-hemolytic, they can be
differentiated by the bile solubility test and their susceptibility to optochin
D. No correct answer
E. *Viridans streptococci are identified by Lance-field grouping, which is based on the C
carbohydrate in the cell wall
For staining the smear from liquor such method may be used:
A. Ziehl-Neelsen
B. Loeffler
C. Burry
D. Roux
E. *Gram
From which site is a-hemolytic Streptococcus isolate most likely to have spread in blood?
A. Anterior nares.
B. Lower respiratory tract.
877.
878.
879.
880.
881.
882.
883.
884.
885.
C. Distal urethra.
D. Facial skin.
E. *Oropharynx.
Gonococci are pathogenic for:
A. Rabbit
B. Mice
C. Sheep
D. Rat
E. *Human
Gonococcus is pathogenic for:
A. Rabbits
B. Mice
C. Sheep
D. Rats
E. *No correct answer
How does Protein A aid in virulence?
A. Hydrolyzes secretory IgA.
B. Binds Factor H, prevents activation of complement.
C. Extracts iron from plasma proteins.
D. Promotes tight binding of bacteria to extracellular matrix.
E. *Binds the Fc region of IgG, decreases opsonization.
How we can distinguish S. aureus from staphylococci epidermidis?
A. Production of catalase.
B. Colony color when grown on BHI agar.
C. Ability to grow on MacConkey agar.
D. Type of hemolysis on sheep blood agar.
E. *Production of coagulase.
In a bacterium, where are proteins synthesized?
A. nucleus
B. peroxisome
C. nucleoid region
D. capsule
E. *ribosomes
In serum broth Meningococci produce:
A. No visible changes
B. Sedimentation
C. All answers are correct
D. There is no correct answer
E. *Turbidity and a sediment at the bottom of the test tube
Indicate biological properties of Staphylococci:
A. produce urease
B. produce catalase
C. produce phosphatase and hydrogen sulphide
D. No correct answer
E. *All answers are correct
Indicate properties of Group A streptococci
A. Catalase “–“
B. Beta-hemolysis
C. Bacitracin sensitive
D. There is no correct answer
E. *All answers are correct
What microbes do look like irregular grapelike clusters?
A. streptobacilli
B. diplobacilli
C. coccus
D. Sarcina
E. *staphylococcus
886.
A.
B.
C.
D.
E.
887.
A.
B.
C.
D.
E.
888.
A.
B.
C.
D.
E.
889.
A.
B.
C.
D.
E.
890.
A.
B.
C.
D.
E.
891.
A.
B.
C.
D.
E.
892.
A.
B.
C.
D.
E.
893.
A.
B.
C.
D.
E.
894.
A.
B.
C.
D.
E.
895.
A.
B.
Leucocidin, a substance which destroys:
Leucocytes
Haematoblasts of the bone marrow
Nerve cells
No correct answer
*All answers are correct
Leukocidins are
enzymes contained in the lysosomes of phagocytes to kill ingested bacteria
proteins produced by bacteria that kill closely-related bacteria
proteases produced by bacteria which destroy host immunoglobulins
enterotoxins produced by Staphylococcus aureus involved in food-borne disease
*substances produced by pyogenic bacteria that kill phagocytes
Meningococci were described by:
Pasteur
Koch
Bilroth
Loeffler
*Weichselbaum
Most strains of Staphylococcus aureus show:
?-haemolysis on sheep blood agar.
phosphatase production.
novobicin resistance
all are right.
*a golden-yellow pigment.
Neisseria gonorrhoeae is classified with _____.
proteobacteria
chlamydias
spirochetes
cyanobacteria
*gram-negative bacteria
Neisseria meningitidis is classified with _____.
proteobacteria
chlamydias
spirochetes
cyanobacteria
*gram-negative bacteria
Pathogens that are usually beta-hemolytic include
*Staphylococcus aureus.
Streptococcus Group D
Streptococcus pneumoniae.
Staphylococcus epidermidis
all answers are correct
Patient has streptococcal pneumonia. What tested material is used for inoculation?
Pus
Cerebrospinal fluid
Blood
Post-mortem organs
*Sputum
Penicillin-resistant Staphylococcus can be treated with ______ without sensitivity testing.
ampicillin
erythromycin
methicillin
amoxycillin
*no antibiotic
Pili increase the virulence in which of the following?
Treponema pallidum
Mycobacterium tuberculosis
896.
897.
898.
899.
900.
901.
902.
903.
904.
C. Clostridium welchii
D. Neisseria meningitidis
E. *Neisseria gonorrhea
Rheumatic fever damages the _______, and glomerulonephritis damages the______
A. skin, heart
B. joints, bone marrow
C. brain, kidney
D. heart, bone marrow
E. *heart valves, kidney
Rheumatic Fever has such etiology:
A. Neisserial
B. Staphylococcal
C. Moraxella
D. Peptostreptococcal
E. *Streptococcal
Scalded skin syndrome is due to which toxin of Staphylococcus aureus?
A. Enterotoxin.
B. Leucocidin.
C. Haemolysin
D. Necrotoxin
E. *Epidermolytic toxin.
Scarlet fever has such etiology:
A. Neisserial
B. Staphylococcal
C. Moraxella
D. Peptostreptococcal
E. *Streptococcal
Sensitivity to bacitracin would best be determined by growing the test organism on
A. eosin methylene blue agar.
B. carbohydrate fermentation broth.
C. MacConkey agar.
D. All media would be equally suitable.
E. *blood agar.
Show biological properties of Staphylococci:
A. liquefy gelatin
B. coagulate milk and occasionally serum
C. reduce nitrates to nitrites
D. No correct answer
E. *All answers are correct
Show enzyme with destructive properties
A. Hyaluronidasa
B. Phosphatasa
C. Lecithinase
D. No correct answer
E. *All answers are correct
Show fermentative properties of Meningococci:
A. do not liquefy gelatin
B. cause no change in milk
C. ferment glucose with acid formation
D. ferment maltose with acid formation
E. *ferment glucose and maltose with acid formation
Specimens for microscopic examination in patients with gonorrhoeae:
A. discharge of the urethra,
B. discharge of the vagina,
C. discharge of the vulva
D. There is no correct answer
E. *All answers are correct
905.
A.
B.
C.
D.
E.
906.
A.
B.
C.
D.
E.
907.
A.
B.
C.
D.
E.
908.
A.
B.
C.
D.
E.
909.
A.
B.
C.
D.
E.
910.
A.
B.
C.
D.
E.
911.
A.
B.
C.
D.
E.
912.
A.
B.
C.
D.
E.
913.
A.
B.
C.
D.
E.
914.
A.
B.
Staphylococcus aureus is classified with _____.
proteobacteria
chlamydias
spirochetes
cyanobacteria
*gram-positive bacteria
Staphylococcus aureus, a major pathogen, is usually
alpha hemolytic.
gamma hemolytic.
delta hemolytic.
incapable of hemolysis.
*beta hemolytic.
Staphylococcus grows on/in the ______________ of warm-blooded animals
teeth
large intestines
No correct answer
All answers are correct
*skin and mucus membranes
Streptococcus pyogenes is classified with _____.
proteobacteria
chlamydias
spirochetes
cyanobacteria
*gram-positive bacteria
The carrier site in humans for pathogenic Neisseria meningitidis is the
conjunctiva
urogenital tract
blood
meninges
*nasopharynx
The causative agent of gonorrhea is
Neisseria meningitidis
Treponema pallidum
gonorrhea mycobacterium
Neisseria meningitidis
*Neisseria gonorrhea
The causative agent of otitis media
Streptococcus pneumoniae (pneumococcus)
Corynebacterium diphtheriae
Borrelia burgdorferi
Neisseria meningitidis
*Streptococcus pyogenes
The causative agent of rheumatic fever
Neisseria meningitidis
Staphylococcus aureus
Francisella tularensis
Staphylococcus epidermidis
*Streptococcus pyogenes
The causative agent of toxic shock syndrome
Neisseria gonorrhea
Salmonella typhi
Treponema pallidum
Staphylococcus epidermidis
*Staphylococcus aureus
The coagulase test is used to differentiate Staphylococcus aureus from
other staphylococci
micrococci
C. enterococci
D. pneumococci
E. *streptococci
915.
The coagulase test, in which the bacteria cause plasma to clot, is used to distinguish
A. Streptococcus pyogenes from Enterococcus faecalis
B. Streptococcus pyogenes from Staphylococcus aureus
C. Staphylococcus epidermidis from Neisseria meningitides
D. All are right
E. *Staphylococcus aureus from Staphylococcus epidermidis
916.
The Gonococci do not grow on common media. They grow readily at pH 7.2-7.4 on media to
which _________ has been added.
A. Glucose
B. Bile
C. Urine
D. No correct answer
E. *Serum
917.
The gonococcus possesses low biochemical activity and no proteolytic activity. It ferments only
_____________ with acid formation
A. Maltose
B. Mannitol
C. Saccharose
D. All answers are correct
E. *Glucose
918.
The Kirby-Bauer test is used to determine
A. which carbohydrates a bacteria can ferment.
B. if the bacteria can produce gelatinase.
C. if the organism can produce catalase.
D. the type of hemolysis a bacteria is capable of producing.
E. *which antibiotics a bacterium is susceptible to.
919.
The laboratory informs you that an isolate of Staphylococcus aureus is ‘methicillin-resistant’.
Which phrase below best describes such isolates?
A. Although resistant to methicillin, nearly all are sensitive to cephalosporins.
B. They are seldom resistant to antibiotics other than ?-lactams.
C. They produce a ?-lactamase active on both cephalosporins and penicillins.
D. The ‘methicillin-resistance’ gene also confers resistance to vancomycin.
E. *They are resistant to both ‘anti-staph’ penicillins and cephalosporins.
920.
The main carrier site on the human body for strains of potentially pathogenic Staphylococcus
aureus is the
A. oral cavity
B. nasal membranes
C. gastrointestinal tract
D. vagina
E. *throat (posterior nasopharynx)
921.
The main carrier site on the human body for strains of potentially pathogenic Neisseria
meningitidis is the
A. nasal membranes
B. oral cavity
C. gastrointestinal tract
D. vagina
E. *throat (posterior nasopharynx)
922.
The meningococcus is an aerobe or facultative anaerobe and does not grow on common media. It
grows readily at pH 7.2-7.4 on media to which _________ has been added.
A. Glucose
B. Bile
C. Urine
D. No correct answer
E. *Serum
923.
The MOST important contribution of the capsule of Streptococcus pneumoniae to virulence is
A. To prevent dehydration of the organisms on mucosal surfaces
B. To inhibit polymorphonuclear leukocyte chemo taxis
C. To accelerate tissue invasion by its collage-naselike activity
D. All are right
E. *To retard phagocytosis by polymorphonuclear leukocytes
924.
The MOST important way the host circumvents the function of the pneumococcal
polysaccharide capsule is via
A. T lymphocytes sensitized to polysaccharide antigens
B. Polysaccharide-degrading enzymes
C. Activated macrophages
D. All are right
E. *Anticapsular antibody
925.
The most severe streptococcal diseases are caused by
A. group B streptococci
B. group C streptococci
C. pneumococci
D. enterococci
E. *group A streptococci
926.
The Neisseria gonorrhoeae does not grow on common media. It grows readily on media to which
_________ has been added.
A. Glucose
B. Mannitol
C. Bile
D. Yolk
E. *Ascitic fluid
927.
The organism that produced the plasmocoagulase is most likely
A. Staphylococcus epidermidis
B. Streptococcus pyogenes.
C. Streptococcus pneumoniae.
D. Streptococcus mitis.
E. *Staphylococcus aureus.
928.
The presence of viable bacteria in the blood stream:
A. serum poisoning
B. antisepsis
C. mixed infection
D. anemia
E. *bacteremia
929.
The similarity between the toxic shock syndrome toxin (TSST), the staph enterotoxins, and the
erythrogenic toxin (pyogenic exotoxin) is
A. they are all produced by Staphylococcus aureus
B. the pathology of the diseases that they cause is identical
C. they are all neurotoxins
D. they are the same (identical) toxin produced by three different organisms
E. *they stimulate the immune system in a similar manner as superantigens
930.
The skin blotches in meningitis are due to
A. blood clots
B. erysipelas
C. exotoxin in skin
D. E.skin invasion by N. meningitidis
E. *endotoxins in the blood
931.
The streptococcal invasin which behaves as a "spreading factor" by breaking down the
framework of connective tissues is called
A. collagenase
B. streptokinase
C. streptolysin
D. erythrogenic toxin (pyogenic exotoxin)
E. *hyaluronidase
932.
The symptoms in scarlet fever are due to
A. streptolysin
B. coagulase
C. alpha toxin
D. leucocidin
E. *pyrogenic toxin
933.
Tissue-degrading enzymes play an important role in the pathogenesis of several bacteria. Which
one of the following is NOT involved in tissue or cell damage?
A. Lecithinase of Clostridium perfringens
B. Hyaluronidase of Streptococcus pyogenes
C. Leukocidinof Staphylococcus aureus
D. All are right
E. *M protein of Streptococcus pneumoniae
934.
Under anaerobic conditions pathogenic staphylococci break _________to acid:
A. blood
B. yolk
C. urine
D. tregalose
E. *mannitol
935.
Viridans streptococci commonly cause
A. pneumonia
B. meningitis
C. otitis media
D. arthritis
E. *subacute endocarditis
936.
What are features of Pneumococci?
A. Their cells are arranged in pairs
B. Their cells are elongated, resembling a candle flame
C. Their cells and are surrounded with a capsule
D. There is no correct answer
E. *All answers are correct
937.
What bacterial structure or substance is primarily associated with antigenic variation in the
Group A streptococci?
A. outer membrane protein (omp)
B. streptokinase
C. hyaluronic acid capsule
D. M-protein
E. *Polysaccharide
938.
What do endotoxins and exotoxins have in common?
A. secreted into the medium
B. heat stable
C. heat resistent
D. contain polysaccharide
E. *cause damage to the host
939.
What do we use for specific prophylaxis of meningococcal infection?
A. Antibiotics
B. Sulfonamides
C. Toxoid
D. Immunoglobulin
E. *Vaccine
940.
What drug is used for specific prophylaxis of staphylococcal infection?
A. antitoxic serum
B. antibiotics
C. sulphonamides
D. No correct answer
E. *staphylococcal toxoid
941.
What drug is used for specific treatment of staphylococcal infection?
A. staphylococcal anatoxin
B. antibiotics
C. sulphonamides
D. No correct answer
E. *antitoxic serum
942.
What enzyme does possess destructive properties?
A. Coagulase
B. Fibrinolysin
C. Lecithinase
D. No correct answer
E. *All answers are correct
943.
What erythrocytes are the most sensitive to the staphylococcal haemotoxin?
A. pig’s, cat’s
B. chicken’s, duck’s
C. all are correct
D. No correct answer
E. *rabbit’s, sheep’s
944.
What group-specific polysaccharide do Streptococci produce?
A. A
B. B
C. D
D. E
E. *C
945.
What is optimal ph for staphylococci?
A. 3.2-3.4
B. 4.2-4.4
C. 5.2-5.4
D. 6.2-6.4
E. *7.2-7.4
946.
What is the G+C content in DNA
A. 20.0-32.0
B. 40.5-51.0
C. 52.0-61.4
D. 63/0-70.0
E. *30.7-39.0
947.
What is the most common cause of urinary tract inf::What is the most common cause of urinary
tract infections?
A. Staphylococcus saprophyticus
B. Escherichia coli
C. Streptococcus bovis
D. Staphylococcus epidermidis
E. *Enterococcus fecalis
948.
What is the optimal temperature for Streptococci growth?
A. 17 1C
B. 27 2C
C. 47 4C
D. 57 5C
E. *37 3C*
949.
What name is given to the rigid structure, found outside the plasma membrane that surrounds
and supports the bacterial cell?
A. capsule
B. pili
C. flagella
D. nucleoid region
E. *cell wall
950.
What nucleoprotein substance do Streptococci produce?
A.
B.
C.
D.
E.
951.
A.
B.
C.
D.
E.
952.
A.
B.
C.
D.
E.
953.
A.
B.
C.
D.
E.
954.
A.
B.
C.
D.
E.
955.
A.
B.
C.
D.
E.
956.
A.
B.
C.
D.
E.
957.
A.
B.
C.
D.
E.
958.
A.
B.
C.
D.
E.
959.
A.
B.
C.
A
C
N
O
*P
What nutrient medium is used for inoculation of blood in patient with bacteremia?
Glucouse agar
Yolk salt agar
Yolk salt broth
1 % alkaline peptone water
*Glucose broth
What nutrient medium is used for inoculation of blood for diagnosis of Streptococcal sepsis?
Yolk salt agar
Yolk salt broth
1 % alkaline peptone water
Glucouse agar
*Glucose broth
What nutrient medium is used for inoculation of blood for diagnosis of Pneumococcal sepsis?
Endo’s medium
Yolk salt broth
Blood broth
Glucose agar
*Serum broth
What nutrient medium may be used for primary isolation of staphylococci from tested material?
Endo’s medium
Levin’s medium
Loeffler’s medium
Koch’s medium
*Blood agar
What nutrient medium may be used for primary isolation of staphylococci from tested material?
Loeffler’s medium
Koch’s medium
Ploskirev’s medium
TCBS
*Yolk salt agar
What pigment do staphylococci produce?
Golden
White
Lemon-yellow
No correct answer
*All answers are correct
What plasma is used for detection of plasmocoagulase activity?
citrated horse plasma
citrated human plasma
citrated chicken plasma
No correct answer
*citrated rabbit plasma
What streptolysins do Streptococci produce?
A and B-streptolysin
P and S-streptolysin
M- and N-streptolysin
W- and S-streptolysin
S-streptolysin
What type of haemolysin do staphylococci produce?
ABC-
D. DE. *All answers are correct
960.
What type-specific protein do Streptococci produce::What type-specific protein do Streptococci
produce?
A. R- and T-substances
B. P- and T-substances
C. and T-substances
D. P- and A-substances
E. *M- and T-substances
961.
Where is a bacterial cell's DNA found?
A. ribosomes
B. nucleus
C. peroxisome
D. capsule
E. *nucleoid region
962.
Which bacterial invasin is mismatched with its activity in the host?
A. staphylokinase: degrades fibrin
B. coagulase: clots fibrin
C. streptolysin: lyses neutrophil membranes
D. none of the above
E. *hyaluronidase: degrades the ground substance of connective tissue
963.
Which genus of bacteria has pathogens that can cause blindness and deafness?
A. Branhamella
B. Staphylococcus
C. Streptococcus
D. Shigella
E. *Neisseria
964.
Which infectious agent of those covered in the chapter would most likely be acquired from a
contaminated doorknob?
A. Staphylococcus epidermidis
B. Streptococcus pyogenes
C. Neisseria meningitidis
D. Streptococcus pneumoniae
E. *Staphylococcus aureus
965.
Which of the following agents is the commonest cause of infective endocarditis?
A. Staphylococcus epidermidis.
B. Candida spp.
C. Coliforms.
D. Rickettsia
E. *Viridans group of streptococci.
966.
Which of the following are pyogenic cocci:
A. Streptococcus
B. Staphylococcus
C. Pneumococcus
D. Neisseria
E. *all of these
967.
Which of the following bacteria ferment mannitol anaerobically?
A. S. epidermidis.
B. S. saprophyticus.
C. S. canis
D. all are false.
E. *Staphylococcus aureus.
968.
Which of the following best describes the pathogenesis of acute rheumatic fever?
A. due to an immunologic cross reaction between heart muscle and Staphylococcus aureus
B. involves B-hemolytic Streptococci growing in the heart
C. is a complication of Group A Streptococcal skin disease as well as pharyngitis
D. tonsilitis is first stage of development of rheumatic fever
969.
970.
971.
972.
973.
974.
975.
976.
977.
978.
E. *characterized by inflammation of the heart and/or the joints
Which of the following causes epidemic meningitis?
A. Streptococcus pneumoniae
B. Francisella tularensis
C. Staphylococcus aureus
D. Moraxella catarrhalis
E. *Neisseria meningitidis
Which of the following is a normal skin resident?
A. Staphylococcus aureus
B. Thermoactinomyces vulgaris
C. Streptococcus pyogenes
D. Streptococcus cremosis
E. *Staphylococcus epidermidis
Which of the following is a pathogen of the oropharynx?
A. Streptococcus pneumoniae
B. Streptococcus bovis
C. Streptococcus viridans
D. Enterococcus faecalis
E. *Streptococcus pyogenes
Which of the following is associated with dental caries?
A. Streptococcus pneumoniae
B. Lactococcus lactis
C. Staphylococcus aureus
D. Moraxella catarrhalis
E. *Streptococcus mutans
Which of the following is NOT true of Neisseria gonorrhea?
A. Is a mucosal pathogen
B. Can disseminate in the immunosuppressed
C. Complications include ectopic pregnancy, PID and sterility
D. Gram-negative diplococci
E. *Requires a vaginal pH of 5 or more to grow
Which of the following is NOT true of Neisseria meningitidis?
A. Crosses the blood brain barrier
B. Colonizes nasopharynx
C. Predisposed groups include diabetics
D. Has peptidoglycan
E. *Has 3 serotypes - A, B, Y
Which of the following organisms may lead to pseudomembrane formation in the throat?
A. Corynebaclerium diphtheriae
B. Treponema Vinsentii
C. Streptococcus pyogenes.
D. Candida albicans.
E. *All are correct
Which of the following statements about gonorrhea is true?
A. Men are frequently asymptomatic carriers.
B. Bacteremia is common.
C. Serologic diagnosis is more reliable than culture.
D. Penicillins are no longer recommended for treatment.
E. *Gonococci are within leucocytes in a sample
Which of the following statements best describes Streptococcus pneumoniae?
A. bile soluble, catalase negative, noncapsulated
B. bile soluble, gramnegative, optochin resistant
C. bile soluble, catalase positive, optochin sensitive
D. bile soluble, catalase negative, motily
E. *bile soluble, optochin sensitive, capsulated
Each of the following agents is a recognized cause of diarrhea EXCEPT:
A. Clostridium perfringens
B.
C.
D.
E.
Escherichia coli
Vibrio cholerae
All are right
*Enterococcus faecalis
979.
Which one of the following is considered a virulence factor for Staphylococcus aureus?
A. A heat-labile toxin that inhibits glycine release at the internuncial neuron
B. An oxygen-labile hemolysin
C. Resistance to novobiocin
D. All are correct
E. *Protein A that binds to the Fc portion of IgG
980.
Which one of the following is NOT an important characteristic of either Neisseria gonorrhoeae
or Neisseria meningitidis?
A. Polysaccharide capsule
B. IgA protease
C. Pili
D. All are right
E. *M protein
981.
Which one of the following is NOT an important characteristic of Streptococcus pyogenes?
A. M protein
B. Beta-hemolysin
C. Polysaccharide group-specific substance
D. All are right
E. *Protein A
982.
Which organism below is most likely?
A. Pseudomonas aeruginosa
B. Klebsiella pneumoniae
C. Haemophilus influenzae
D. Neisseria gonorrhoeae
E. *Neisseria meningitidis
983.
Which statement below most accurately describes the role of M protein in virulence of Group A
Streptococci [Streptococcus pyogenes]?
A. Shows no antigenic variation, so is not a target for antibodies.
B. Is a ‘superantigen toxin’ which stimulates Th cells.
C. Binds Fc regions of Immunoglobulin G molecules.
D. Inhibit phagocytosis
E. *Stimulates synthesis of antibodies that cross-reacts with heart tissue.
984.
Which test below would best distinguish S. aureus from one of the less-virulent staphylococci?
A. Production of catalase.
B. Colony color when grown on BHI agar.
C. Ability to grow on MacConkey agar.
D. Type of hemolysis on sheep blood agar.
E. *Production of coagulase.
985.
Which test result would rule out an Enterococcus isolate?
A. growth in 6.5% NaCl
B. catalase negative
C. PYR positive
D. motility
E. *oxidase positive
986.
Which virulence factor results in the symptoms of Staphylococcal food poisoning?
A. exfoliative exotoxin
B. hyaluronidase
C. endotoxin
D. neurotoxin
E. *enterotoxin
987.
Who did discover gonococci first?
A. Pasteur
B. Koch
C. Weichselbaum
D. Loeffler
E. *Neisser
988.
Who did discover Staphylococci?
A. Pasteur
B. Ivanovsky
C. Loeffler
D. Mueller
E. *Koch
989.
Who did discover streptococci first?
A. Pasteur
B. Koch
C. *Billroth
D. Loeffler
E. Rosenbach
990.
Who did study Staphylococci in details?
A. Pasteur
B. Koch
C. Ivanovsky
D. Rosenbach
E. *Loeffler
991.
23-year-old woman comes to your office because, for 3 days, she has experienced burning with
urination, increased frequency of urination, and a continual feeling that she needs to urinate. She does
not have vaginal discharge, fever, or flank pain. Rapid 'dipstick' urine tests are consistent with
uncomplicated cystitis. Culture of urine on standard media produces a lactose-fermenting Gramnegative rod. In situations such as this, what is the most likely pathogen?
A. Enterobacter faecium
B. Klebsiella pneumoniae
C. Proteus vulgaris
D. Pseudomonas aeruginosa
E. *Escherichia coli
992.
A 20-year-old college student goes to the student health center because of dysuna, frequency,
and urgency on urination for 24 hours. She has recently become sexually active. On urmalysis, many
polymorphonuclear cells are seen. The most likely organism responsible for these symptoms and signs
is
A. Staphylococcus aureus
B. Streptococcus agalactiae
C. Gardnerella vaginalis
D. Lactobacillus species
E. *Escherichia coli
993.
A 23-year-old woman has a history of recurrent urinary tract infections, including at least one
episode of pyelonephritis. Blood typing shows the P blood group antigen. Which of the following is
likely to be the primary cause of her infections7
A. Escherichia coli that produce heat-stable toxin
B. Escherichia coli with K1 (capsular type 1) antigen
C. Escherichia coli O139 (lipopolysaccharide O antigen 139)
D. Escherichia coli O157 H7 (lipopolysaccharide O antigen 157, flagellar antigen
E. *Escherichia coli with P-pili (fimbriae)
994.
A 27 year-old woman is admitted to the hospital because of fever, with increasing anorexia,
headache, weakness, and altered mental status of 2 days'duration. She works for an airline as a cabin
attendant, flying between the Indian subconti nent and other places in Southeast Asia and the West
Coast of the USA. Ten days prior to admission she had a diarrheal illness that lasted for about 36 hours.
She has been constipated forthe last 3 days. Her temperature is 39 °C, heart rate 68/min, blood pressure
120/80 mm Hg, and respirations 18/mm. She knows who she is and where she is but does not know the
date. She is picking at the bed clothes. Rose spots are seen on the trunk. The remainder of the physical
examination is normal. Blood cultures are done and an intravenous line is placed. The most likely cause
of her illness is
A.
B.
C.
D.
E.
Enterotoxigenic Escherichia coli (ETEC)
Shigella sonnei
Salmonella enterica subspecies enterica serotype Typhimunum (Salmonella Typhimurium)
Enteroinvasive Escherichia coli (EIEC)
*Salmonella enterica subspecies enterica serotypeTyphi (SalmonellfaTyphi)
995.
A 60-year old man was admitted to the hospital 2 weeks previously because of head trauma and
other injuries that resulted from an automobile accident. A urinary tract catheter was inserted at
admission and remains in place. The man develops a urinary tract infection with a gram negative
bacillus. The probable cause of this patients infection is
A. Pseudomonas aeruginosa
B. Providenaa rettgeri
C. Escherichia coli
D. Morganella morgana
E. *Indeterminable without culture and identification testing
996.
A common serotype of enterohemorrhagic E. coli is ::A common serotype of enterohemorrhagic
E. coli is O157:H7. To which bacterial structure does the "H7" correspond?
A. Pili.
B. Capsule.
C. LPS core polysaccharide.
D. Porins.
E. *Flagella.
997.
A five-day-old child develops high fever and stiff neck. A spinal tap is performed. A Gramstained smear of cerebrospinal fluid reveals many neutrophils and short, thick, Gram-negative rods of
uniform length. This microbes can ferment lactose.Which organism below is most likely to have caused
this infection?
A. Haemophilus influenzae
B. Streptococcus pneumoniae
C. Neisseria meningitidis
D. Streptococcus agalactiae
E. *Escherichia coli
998.
A lactose-fermenting Gram-negative rod is isolated from the bloody stool of a young child.
Which pathogen is most likely?
A. Salmonella enterica.
B. Vibrio cholerae.
C. Shigella dysenteriae.
D. Clostridium difficile.
E. *Escherichia coli.
999.
A patient becomes infected with Salmonella enterica serotype typhi. Which condition would
most strongly favor development of a “chronic carrier state” with this organism?
A. Age over 70 years.
B. Infection via the respiratory route.
C. Kidney stones.
D. Chronic pulmonary disease.
E. *Gallstones.
1000.
A patient with septicemia goes into septic shock. Blood cultures later showed the pathogen to be
Escherichia coli. Which component of the bacteria was most likely to have produced shock?
A. Capsular polysaccharide.
B. Teichoic acid.
C. A superantigen toxin.
D. Plasma membrane lipids.
E. *Lipopolysaccharide [LPS].
1001.
A reason not to administer beta lactam antibiotics for a Gram-negative septicemia (blood-borne
infection), unless there is no other alternative, is
A. the antibiotic eliminates the normal flora
B. the lysis of bacterial cells increases the activity of bacterial LPS
C. Complement activation cannot occur in the presence of the antibiotic
D. the antibiotic suppresses the immune response necessary to eliminate the pathogen
E. *beta lactam antibiotics are ineffective against Gram-negative bacteria
1002.
A seven-day-old child develops high fever and stiff neck. A spinal tap is performed. A Gramstained smear of cerebrospinal fluid reveals many neutrophils and short, thick, Gram-negative rods of
uniform length. This microbes can ferment lactose.Which organism below is most likely to have caused
this infection?
A. Haemophilus influenzae
B. Streptococcus pneumoniae
C. Neisseria meningitidis
D. Streptococcus agalactiae
E. *Escherichia coli
1003.
A sexually-active woman develops a urinary tract infection which ascends to the kidneys. Blood
culture yields a ?-hemolytic Gram-negative rod. In this situation, which pathogen is most common?
A. Klebsiella pneumoniae.
B. Pseudomonas aeruginosa.
C. Salmonella enteritidis.
D. Serratia marcescens
E. *Escherichia coli.
1004.
A specimen of thick, bloody sputum from a hospitalized 80-year-old patient with chronic
obstructive pulmonary disease is sent for laboratory analyses. The tests yield heavy growth of a lactosepositive, nonmotile, gram-negative rod with a large gelatinous capsule. Which of the following is this
bacterium most likely to be?
B. coli
A. Enterobacter aerogenes
B. P. aeroginosa
C. Y. pseudotuberoulosis
D. *K. pneumoniae
1005.
A stool sample is plated on standard Endo -agar plates. After overnight incubation some of the
colonies are dark pink in color, others are pale, nearly colorless. What can you conclude about the
bacteria that produced dark-pink colonies?
A. Gram-positive.
B. Not likely to be ‘normal flora’.
C. Non-motile.
D. Produce capsules
E. *Ferment lactose.
1006.
A strain of bacteria produced colorless colonies when cultured on standard MacConkey agar. It
was then used to inoculate a Sugar-Iron Agar slant. After overnight incubation, the tube was entirely
yellow and there were numerous bubbles inside the agar. There is no black precipitate. Which of the
following descriptions most accurately describes the metabolic reasons for these observations?
A. Produces H2S and gas
B. *Ferments lactose and produces gas
C. Ferments sucrose and produces gas.
D. Ferments neither lactose nor sucrose
E. Ferments glucose only
1007.
A vacationer develops watery diarrhea but not chills or fever. In this setting which of the
following pathogens is the most common?
A. Salmonella enterica
B. Staphylococcus aureus
C. Campylobacter jejuni
D. Helicobacter pylori
E. *Escherichia coli
1008.
A vacationer has “Traveler’s diarrhea” produced by enterotoxigenic E. coli. His profuse watery
diarrhea is produced by a protein exotoxin secreted by this bacterium. Which statement below best
describes the effect of this exotoxin?
A. Kills enterocytes and produces ulceration and inflammation.
B. Paralyzes phagocytosis by neutrophils.
C. Blocks adsorption of nutrients by enterocytes.
D. Causes rearrangement of the enterocyte cytoskeleton and disappearance of the brush border.
E. *Stimulates ion transport by enterocytes into the intestinal lumen.
1009.
A vacationing couple both develop severe watery diarrhea which lasts three days. Which
organism is the most common etiologic agent of such infections?
A. Shigella sonnei.
B. Pseudomonas aeruginosa
C. Salmonella typhi.
D. Campylobacter jejuni.
E. *Escherichia coli.
1010.
A young woman develops urgency, frequency, and dysuria. Two days later she develops fever,
chills, and costovertebral angle tenderness. Tests of urine for leukocyte esterase and nitrate reductase are
positive. Urine culture yields a beta-hemolytic Gram-negative rod which forms dark-pink colonies on
MacConkey agar. Which of the following organisms is most likely?
A. Pseudomonas aeruginosa
B. Klebsiellla pneumoniae
C. Staphylococcus saprophyticus
D. Enterobacter, sp
E. *Escherichia coli
1011.
A young woman has a urinary tract infection caused by E. coli. By what route are such infections
most commonly acquired?
A. Respiratory route, followed by spread from the anterior nares.
B. Respiratory route, followed by spread from the oro-pharyngeal region.
C. Intestinal infection, followed by spread of bacteria to the urethra via the bloodstream.
D. Direct contact route
E. *Fecal-oral route, followed by colonization of the intestine and then the perineum.
1012.
A young woman has a urinary tract infection caused by E. coli. By what route are such infections
most commonly acquired?
A. Respiratory route, followed by spread from the anterior nares.
B. Respiratory route, followed by spread from the oro-pharyngeal region.
C. Intestinal infection, followed by spread of bacteria to the urethra via the bloodstream.
D. Direct contact route
E. *Fecal-oral route, followed by colonization of the intestine and then the perineum.
1013.
After inoculation of Escherichia coli on Ploskirev medium the growth of bacteria is inhibited.
What chemical does predetermine this phenomenon?
A. oxalic acid
B. sodium sulphite
C. Bismuth salts
D. fuchsin
E. *brilliant green
1014.
After inoculation of faces of the patient Escherichia coli on Ploskirev medium the growth of
bacteria is inhibited. What chemical does predetermine this phenomenon?
A. oxalic acid
B. sodium sulphite
C. Bismuth salts
D. Fuchsin
E. brilliant green
1015.
After inoculation of the patient’s faces on Endo medium there were grown to types of colonies:
one – red with metallic hue, other - colorless. To what group of nutrient media does Endo medium
belong to?
A. Elective
B. Enriching media
C. Universal
D. Selective
E. Differential diagnostic
1016.
After inoculation of the patient’s faces on Endo medium there were grown to types of colonies:
one red with metallic hue, other - colorless. To what group of nutrient media does Endo medium belong
to?
A. Elective
B.
C.
D.
E.
Enriching media
Universal
Selective
*Differential diagnostic
1017.
What changes will seen in Olkenitsky medium when Salmonella typhi was inoculated in it?
A. To fix the hydrogen sulphide production in this medium is impossible
B. appearance of greenish precipitate in the column of agar
C. appearance of bright red precipitate in the column of agar
D. all medium will be black
E. *appearance of black precipitate in the column of agar
1018.
An old man has a urinary tract infection caused by E. coli. By what route are such infections
most commonly acquired?
A. Respiratory route, followed by spread from the oro-pharyngeal region.
B. Respiratory route, followed by spread from the anterior nares.
C. Intestinal infection, followed by spread of bacteria to the urethra via the bloodstream.
D. coli spreads from skin
E. *Fecal-oral route, followed by colonization of the intestine and then the perineum.
1019.
An uncommon serotype of Salmonella enterica subspecies enterica was found by laboratories in
the health departments of adjacent states. The isolates were all from a small geographic area on either
side of the border between the states, suggesting a common source for the isolates (All the isolates were
from otherwise healthy young adults who smoked marijuana the same salmo nella was isolated from a
specimen of the marijuana). By what method did the laboratories determine that these isolates were the
same?
A. Capsular (K antigen) typing
B. DNA sequencing
C. Sugar fermentation pattern determination
D. Decarboxylase reaction pattern determination
E. *O antigen and H antigen typing
1020.
Bacteriologists (using the Kauffman-White classifi::Bacteriologists (using the Kauffman-White
classification) made conclusion that outbreak has been caused by Salmonella enterica, serotype
Anatum. Structure of which pair of antigens determined the serotype as Anatum?
A. Heat-labile and heat-stable enterotoxins.
B. Peptidoglycan and teichoic acid.
C. Pili and capsular polysaccharide.
D. Hemolysin and cell-wall-associated carbohydrate.
E. *Flagella and O-antigen.
1021.
Blood cultures from the patient in Question 2 grow a non lactose fermenting gram negative
bacillus. Which of the following is likely to be a constituent of this organism?
A. antigen 157, H antigen 7 (0157 H7)
B. antigen 139(0139)
C. Urease
D. K1 (capsular type l)
E. *Vi antigen (capsule, virulence antigen)
1022.
During a vacation at a Caribbean resort, a 26-year-old executive develops profuse watery
diarrhea. If his illness is produced by E. coli, which virulence factor of this organism is most likely to be
responsible for the diarrhea?
A. A conjugative plasmid that contains antibiotic-resistance transposons.
B. A pathogenicity island which enables E. coli to invade mammalian cells.
C. An iron-transport system more efficient than that present in non-pathogenic E. coli.
D. A toxin that cleaves ribosomal RNA's.
E. *A plasmid-borne gene which encodes a heat-stable peptide toxin that stimulates guanyl cyclase.
1023.
Epidemiologists (using the Kauffman-White classification) report that an outbreak has been
caused by Salmonella enterica, serotype Newport. Structure of which pair of antigens determined the
serotype as Newport?
A. Heat-labile and heat-stable enterotoxins.
B. Pili and capsular polysaccharide.
C. Peptidoglycan and teichoic acid.
D. Hemolysin and cell-wall-associated carbohydrate
E. *Flagella and O-antigen.
1024.
Escherichia coli and Neisseria meningitidis isolated from blood cultures often have transport
systems (for acquiring metal ions from the environment) lacking in their less-virulent relatives. Which
metal is acquired by the majority of these systems?
A. Copper
B. Sodium
C. Potassium
D. Magnesium
E. *Iron
1025.
Escherichia coli was inoculated in Ressel’s medium. What changes will be observed in nutrient
medium, which verify utilization of glucose and lactose?
A. Changes of the color from a pinky to dark blue in the column of agar
B. Changes of the color from pinky to dark blue of the slant surface of agar
C. Changes of the color from a pinky to red of the slant surface of agar
D. Changes of the color from a pinky to red of the column of agar
E. *Changes of the color from a pinky to dark blue in the column of agar and slant surface of agar
1026.
For verifying the peptolytic properties of bacteria what substances are examined in nutrient
medium?
A. carbon acid and water
B. glucose and lactose
C. carbon acid and nitrogen
D. mannitol and methanol
E. indole and hydrogen sulphide
1027.
In Olkenitsky’s medium Escherichia coli was inoculated. What changes will be observed in a
medium, which will confirm utilization of glucose and lactose?
A. The changes of the color from a pinky to yellow in the column of agar
B. The changes of the color from a pinky to yellow of slant surface of agar
C. The changes of the color from a pinky to red of slant surface of agar
D. The changes of the color from a pinky to red of the column of agar
E. *The changes of the color from a pinky to yellow of the column of agar and slant surface of agar
1028.
Olkenitsky’s medium microorganism which products an urea was inoculated. What changes here
will be observed in a medium?
A. appearance of red precipitate in the column of agar
B. appearance of greenish precipitate in the column of agar
C. to fix the urease production in this medium is impossible
D. appearance of brightly-violet precipitate in the column of agar
E. *all will become red
1029.
In Olkenitsky’s medium Salmonella typhi, which decomposes glucose to acid was inoculated.
What changes will be observed in a medium, which certify utilization of glucose?
A. The changes of the color from a pinky to yellow the slant surface of agar
B. The changes of the color from a pinky to red the slant surface of agar
C. The changes of the color from a pinky to yellow of the column of agar and the slant surface of
agar
D. The changes of the color from a pinky to red of the column of agar
E. *The changes of the color from a pinky to yellow of the column of agar
1030.
In Olkenitsky’s medium Salmonella typhi, which forms the hydrogen supplied was inoculated.
What changes will be in a medium in this case?
A. To fix the hydrogen sulphide production in this medium is impossible
B. appearance of greenish precipitate in the column of agar
C. appearance of bright red precipitate in the column of agar
D. all medium will be black
E. *appearance of black precipitate in the column of agar
1031.
Infections with Salmonella enterica, serotype typhi, spread throughout the body. A key to the
ability of serotype typhi to spread systemically is its ability to multiply intracellularly. Multiplication in
which cell type(s) is principally responsible for systemic spread?
A. Basophils.
B.
C.
D.
E.
Enterocytes.
Erythrocytes.
Neutrophils
*Monocytes/macrophages.
1032.
It is necessary to check the quality of antibacterial filters. What microorganism is it possible to
choose as a test-object?
A. Salmonella schottmuelleri
B. Staphylococcus aureus
C. Bordetella pertussis
D. Mycobacterium kansassii
E. *Pseudomonas aeruginosa
1033.
It is necessary to make biochemical identification and examine saccharolytic properties of
bacteria. What media could you offer?
A. Veynberg medium
B. Zeissler medium
C. Kitt-Tarozzi medium
D. Milk
E. *Hiss media
1034.
It is necessary to study ability of microbes to utilize glucose, saccharose, lactose, production of
hydrogen sulphide and utilization of urea. What nutrient media will you recommend?
A. Ru medium
B. Leffler medium
C. Endo medium
D. Ploskirev medium
E. *Olkenitsky medium
1035.
Many isolates of E. coli are now ampicillin-resistant because they produce ?-lactamases. Which
sentence below most accurately describes these enzymes?
A. They inactivate all ?-lactam antibiotics.
B. Although they are produced by many isolates of E. coli, such ?-lactamases are not produced by
other Gram-negative rods.
C. They cause resistance to aminoglycosides as well as b-lactams.
D. They have spread from Gram-negatives like E. coli to Gram-positive pathogens like
E. *Genes which encode them are often present on conjugative plasmids.
1036.
Material from a patient with suspicion on an intestinal infection was inoculated on the Ploskirev
medium. What color do colonies of Escherichia coli have?
A. dark blue
B. colorless
C. brown
D. green
E. *red
1037.
Material from a patient with suspicion on typhoid fever was inoculated on Endo medium. What
color do colony of lactose-negative Salmonella typhi have?
A. dark blue
B. red with metallic hue
C. brown
D. green
E. *colorless
1038.
Microbiologists (using the Kauffman-White classification) report that an outbreak has been
caused by Salmonella enterica, serotype Newport. Structure of which pair of antigens determined the
serotype as Newport?
A. Heat-labile and heat-stable enterotoxins.
B. *Flagella and O-antigen.
C. Pili and capsular polysaccharide.
D. Peptidoglycan and teichoic acid.
E. Hemolysin and cell-wall-associated carbohydrate.
1039.
On the Endo medium colonies of Escherichia and Salmonella were isolated. According to what
signs is it possible to make differentiation between them?
A.
B.
C.
D.
E.
sizes
character of the edges
character of surfaces
consistency
*color
1040.
Salmonella typhi, which utilizes glucose to acid was inoculated in Ressel medium. What changes
will be observed in nutrient medium, which verify utilization of glucose?
A. Changes of the color from a pinky to dark blue of the slant surface of agar
B. Changes of the color from a pinky to red of the slant surface of agar
C. Changes of the color from a pinky to dark blue in the column of agar and slant part of agar
D. Changes of the color from a pinky to red in the column of agar
E. *Changes of the color from a pinky to dark blue in the column of agar
1041.
Several medical students go to Cancun over spring break. One evening, at a local bar, they drink
several pitchers of Margaritas made with crushed ice. They spend the next two days in their hotel room
with severe watery diarrhea, but no chills or fever. By the third day they recover completely. Which
organism is most likely to have been the cause of their illness?
A. Non-typhoidal Salmonella
B. Helicobacter pylori.
C. Campylobacter jejuni.
D. Non-cholera Vibrio.
E. *Enterotoxigenic E. coli.
1042.
The main effect of E. coli and Vibrio cholerae enterotoxin on host cells of the gastrointestinal
tract that leads to the pathology of the diseases, is to
A. inhibit protein synthesis
B. cleave host cell membranes
C. act as superantigens to trigger an overwhelming immunological reaction
D. initiate a localized inflammatory response in the intestine
E. *cause fluid and electrolyte imbalance
1043.
The portion of lipopolysaccharide (endotoxin) molecule that is responsible for a bacterial
antigenic specificity, as well as the existence of multiple serotypes (serovars) among Gram-negative
pathogens, is
A. lipid A
B. KDO
C. R antigen
D. H antigen
E. *O antigen
1044.
Water to be used for parenteral injection must sterilized to kill living microbes and then further
purified to remove non-living bacterial components. Of those listed below, which is the most toxic?
A. Polysaccharides of capsules.
B. Plasma-membrane lipids.
C. Proteins of the outer membrane.
D. Nucleic acids
E. *Lipopolysaccharide.
1045.
What color does acquire the semi-solid Hiss media with the rosolic acid as indicator when
bacteria utilize sugar?
A. *red
B. green
C. brown
D. a color does not change
E. dark blue
1046.
What end products do appear in the liquid Hiss media after fermentation of sugars by E. coli?
A. acid
B. alkali
C. gas
D. fixing the finished goods is not succeeded
E. *acid and gas
1047.
What end products does appear in the semi-solid Hiss media after sugar utilization by
Salmonella?
A. alkali
B. gas
C. acid and gas
D. fixing the finished products is not succeeded
E. *acid
1048.
What nutrient medium is it possible to use for examination of bacterial proteolytic properties?
A. Endo medium
B. Olkenitsky medium
C. MPB
D. Levenshtein-Yensen medium
E. *Milk
1049.
What virulence factor of E. coli is associated with adhesion in the urinary and gastrointestinal
tracts and also binds to a blood group antigen?
A. Colonizing factor antigens
B. Aggregative adherence fimbriae
C. Intimin
D. Ipa protein
E. *pili
1050.
When ampicillin was first introduced, most E. coli isolates were clinically sensitive. Many
isolates are now ampicillin-resistant because they produce ?-lactamases. Which phrase below most
accurately describes these enzymes?
A. Although they are produced by many isolates of E. coli, such ?-lactamases are not produced by
other Gram-negative rods.
B. They inactivate all ?-lactam antibiotics.
C. They cause resistance to aminoglycosides as well as b-lactams.
D. They have spread from Gram-negatives like E. coli to Gram-positive pathogens like
E. *Genes which encode them are often present on conjugative plasmids.
1051.
Which bacteria can produce on Endo medium dark pink colonies?
A. Salmonella enterica
B. Listeria monocytogenes
C. Shigella sonnei
D. Shigella dysenteriae
E. *Escherichia coli
1052.
Which of the following bacteria belong/s to the family Enterobacteriaceae?
A. Shigella.
B. Salmonella.
C. Yersinia.
D. Proteus
E. *All answers are true
1053.
Which of the following descriptions best fits a typical strain of Escherichia coli?
A. motile, aerogenic, non-lactose fermenting, citrate negative
B. non-motile, aerogenic, lactose fermenting mucoid colony
C. motile, anaerogenic, non-lactose fermenting, indole positive
D. motile, anaerogenic, lactose fermenting, sporulated
E. *motile, aerogenic, lactose fermenting, indole positive
1054.
Which of the following does not occur when an individual is infected with Salmonella
enteriditis?
A. Endo toxins cause inflammation and fever
B. Enterotoxins cause diarrhea
C. Cytotoxins lyse Endo thelial cells lining the intestinal tract
D. All answers are true
E. *Proteolytic enzymes cause necrosis
1055.
Which of the following expresses a Shiga toxin which disrupts protein synthesis, leading to
destruction of intestinal villus and decreased absorption with an increase in fluid secretion?
A. Vibrio cholerae
B.
C.
D.
E.
Shigella dysenteriae
ETEC
EIEC
*EHEC
1056.
Which of the following Gram-negative rods ferment glucose, are oxidase negative, ferment
lactose, and are indole positive (tryptophan metabolizing)?
A. Shigella
B. K. pneumoniae
C. Salmonella
D. P. vulgaris
E. *E.coli
1057.
Which of the following Gram-negative rods would indicate a positive MacConkey test in the
lactose fermentation?
A. Shigella
C. pneumoniae
B. Salmonella
C. P. vulgaris
D. *E.coli
1058.
Which of the following has pathogenesis mediated by cytotoxic Shiga toxins as opposed to
plasmid-mediated?
A. Enteropathogenic E. coli (EPEC)
B. Enterotoxigenic E. coli (ETEC)
C. Enteroinvasive E. coli (EIEC)
D. Enteroaggregative E. coli (EAEC)
E. *Enterohemorrhagic E. coli (EHEC)
1059.
Which of the following interacts with G proteins that control adenylate cyclase, leading to the
catabolic conversion of adenosine triphosphate (ATP) to cyclic adenosine monophosphate (cAMP),
resulting in a hypersecretion of water and electrolytes?
A. Vibrio cholerae
B. Shigella dysenteriae
C. ETEC
D. EHEC
E. *EIEC
1060.
Which of the following is an important cause of hemorrhagic colitis (HC) and hemolytic uremic
syndrome (HUS) in the United States?
A. Enteropathogenic E. coli (EPEC)
B. Enterotoxigenic E. coli (ETEC)
C. Enteroinvasive E. coli (EIEC)
D. Enteroaggregative E. coli (EAEC)
E. *Enterohemorrhagic E. coli (EHEC)
1061.
Which of the following is most associated with infant diarrhea in underdeveloped countries;
watery diarrhea and vomiting, and non-bloody stools?
A. Enterotoxigenic E. Coli (ETEC)
B. Enterohemorrhagic E. coli (EHEC)
C. Enteroinvasive E. coli (EIEC)
D. Enteroaggregative E. coli (EAEC)
E. *Enteropathogenic E. coli (EPEC)
1062.
Which of the following is most associated with Traveler diarrhea; infant diarrhea in developing
countries; watery diarrhea, vomiting, cramps, nausea, and low-grade fever?
A. Enteropathogenic E. coli (EPEC)
B. Enterohemorrhagic E. coli (EHEC)
C. Enteroinvasive E. coli (EIEC)
D. Enteroaggregative E. coli (EAEC)
E. *Enterotoxigenic E. coli (ETEC)
1063.
Which of the following produces heat-labile (LT-I and LT-II) and heat-stabile (STa and STb)
enterotoxins that stimulate hypersecretion of fluids and electrolytes?
A. Vibrio cholerae
B.
C.
D.
E.
EHEC
Shigella dysenteriae
EIEC
*ETEC
1064.
Which of the following serotypes of Salmonella can cause gastroenteritis?
A. S. enteritidis.
B. S. Newport.
C. S. typhimurium.
D. S. cholerae suis
E. *All answers are true.
1065.
Which of the following tests may be used to differentiate Salmonella typhi from Shigella
species?
A. glucose fermentation
B. gas production from glucose
C. citrate utilization
D. color of colonies on Endo medium
E. *motility
1066.
Which one of the following organisms causes diarrhea by producing an enterotoxin that activates
adenylate cyclase?
A. Bacteroides fragilis
B. Staphylococcus aureus
C. Enterococcus faecalis
D. All answers are true
E. *Escherichia coli
1067.
Which one of the following organisms that in fects the gastrointestinal tract is the MOST
frequent cause of bacteremia?
A. Shigella flexneri
B. Campylobacter jejuni
C. Vibrio cholerae
D. Salmonella typhi
E. *All answers are true
1068.
What molecule (endotoxin of Gram-negative pathogens) are responsible for a bacterial antigenic
specificity, as well as the existence of multiple serotypes (serovars)?
A. lipid A
B. K antigen
C. R antigen
D. H antigen
E. *O polysaccharide
1069.
Your patient is a 70-year-old man who under went bowel surgery for colon cancer 3 days ago.
He now has a fever and abdominal pain. You are concerned that he may have peritonitis. Which one of
the following pairs of organisms is MOST likely to be the cause?
A. Bordetella pertussis and Salmonella enteritidis
B. Actinomyces israelii and Campylobacter jejuni
C. Clostridium botulinum and Shigella dysente-riae
D. All answers are true
E. *Bacteroides fragilis and Klebsiella pneumoniae
1070.
What is the main effect of E. coli and Vibrio cholerae enterotoxin on host cells of the
gastrointestinal tract that leads to the pathology?
A. inhibit protein synthesis
B. cleave host cell membranes
C. act as superantigens to trigger an overwhelming immunological reaction
D. initiate a localized inflammatory response in the intestine
E. *cause fluid and electrolyte imbalance
Situation tasks
1. An outbreak of sepsis caused by Staphylococcus aureus has occurred in the newborn nursery. You are
called upon to investigate. According to your knowledge of the normal flora, what is the MOST likely
source of the organism?
2.
3.
4.
5.
6.
7.
8.
A. Colon
B. *Nose
C. Throat
D. Vagina
E. Smalll intestine
Residents of an assisted-living facility are immunized against Streptococcus pneumoniae. What is the
antigenic component of the vaccine?
A. A protein toxoid.
B. Killed whole bacteria.
C. Live bacteria of attenuated virulence
D. Purified toxin.
E. *Purified capsular polysaccharides.
A patient with septicemia goes into septic shock. Blood cultures later show the pathogen to be Neisseria
meningitidis. Which component of the bacteria was most likely to be responsible for producing shock?
A. *Lipopolysaccharide [LPS].
B. Teichoic acid.
C. A superantigen toxin.
D. Capsular polysaccharide.
E. Plasma membrane lipids.
A child develops ‘strep throat’ (pharyngitis caused by Streptococcus pyogenes). The pediatrician
explains to the child’s mother that the pharyngitis normally resolves spontaneously but nevertheless it is
important the patient take a full course of Penicillin G. Why is this antibiotic treatment recommended in
this situation?
A. Shortens the course of the infection.
B. Prevents spread of the infection to adjacent sites.
C. *Prevents sequellae such as acute rheumatic fever.
D. Stimulates development of protective immunity.
E. Prevents spread of the infection to others.
A patient has endocarditis produced by an aд-hemolytic Streptococcus. This usually reflects spread of
normal flora to the bloodstream. From which site is this isolate most likely to have spread?
A. Anterior nares.
B. Facial skin.
C. Lower respiratory tract.
D. Distal urethra.
E. *Oropharynx.
A nine years-old child develops high fever and stiff neck. A spinal tap is performed. A Gram-stained
smear of cerebrospinal fluid reveals many neutrophils and Gram-negative cocci that resemble paired
kidney beans within leucocytes. Which organism below is most likely to have caused this infection?
A. Escherichia coli
B. Haemophilus influenzae
C. Listeria monocytogenes
D. *Neisseria meningitidis
E. Streptococcus agalactiae
A patient presented with upper back pain. MRI imaging demonstrated inflammation of the T8-T9
vertebral bodies consistent with osteomyelitis. A bone marrow biopsy, when cultured, produced
colonies of Gram-positive cocci.Colonies on Sheep blood agar were 3-4 mm in diameter, off-white and
beta-hemolytic. Colonies on Brain-heart infusion (BHI) agar were 2-3 mm in diameter and goldenyellow. Catalase and coagulase tests were positive. What was the most likely pathogen?
A. *Staphylococcus aureus
B. Staphylococcus epidermidis
C. Streptococcus pyogenes
D. Streptococcus pneumoniae
E. Streptococcus mitis
A 20-year-old women presents at a local clinic with fever and abdominal tenderness. She reports having
had unprotected sexual intercourse a few weeks earlier. Gram-negative diplococci are seen in a Gram
stain of vaginal secretions; many of the bacteria are inside polymorphonuclear leukocytes. Which
virulence factor is most important in aiding this bacterium to initiate infection?
A. Ability to invade cells.
B. *Adhesive pili.
C. Anti-phagocytic capsule.
D. Endotoxin.
E. Flagella
9. After Gram stain of spinal fluid sample from a patient with meningitis Medical personal during
microscopy examination detected Gram-negative cocci, many in pairs. Which organism below is most
likely?
A. *Neisseria meningitidis
B. Haemophilus influenzae
C. Streptococcus pneumoniae
D. Pseudomonas aeruginosa
E. Escherichia coli
10. A young man has a large pus-filled abscess on his upper arm but does not go to a doctor. Several days
later he is brought to the Emergency Room with fever, hypotension, and multiple organ failure. Which
of the following is most likely to be responsible?
A. Streptococcus pyogenes Erythrogenic toxin.
B. Clostridium perfringens ?-toxin.
C. *Staphylococcus aureus Toxic Shock Syndrome Toxin-1.
D. Shigella dysenteriae Shiga Toxin.
E. Escherichia coli Heat-labile Toxin (ST).
11. Members of a family suffer acute attacks of nausea and vomiting a few hours after returning from a
daylong picnic, at which they ate hamburgers, potato salad, and custard pie. By morning all are feeling
better. Which bacterial toxin is most likely to have caused their symptoms?
A. Clostridium difficile Cytotoxin.
B. Escherichia coli Labile Toxin
C. Escherichia coli Stable Toxin.
D. *Staphylococcus aureus Enterotoxin.
E. Helicobacteri pylori Cytotoxin.
12. Five young men suffer acute attacks of nausea and vomiting a few hours after returning from a student’s
party, at which they ate hamburgers, potato salad, and custard pie. By morning all are feeling better.
Which bacterial toxin is most likely to have caused their symptoms?
A. *Staphylococcus aureus Enterotoxin.
B. Escherichia coli Labile Toxin
C. Escherichia coli Stable Toxin.
D. Clostridium difficile Cytotoxin.
E. Helicobacteri pylori Cytotoxin.
13. E. coli and Neisseria meningitidis isolated from blood cultures often have transport systems (for
acquiring metal ions from the environment) lacking in their less-virulent relatives. Which metal is
acquired by the majority of these systems?
G. Copper
H. Sodium
I. Potassium
J. Magnesium
K. *Iron
14. A 25-year-old woman presents with a swollen, warm, painful knee. Aspirated joint fluid is cloudy and
when cultured on chocolate agar gives rise to oxidase-positive colonies of Gram-negative diplococci.
Which bacterium is most likely to be the cause of this infection?
A. Haemophilus influenzae
B. Staphylococcus aureus
C. Streptococcus pneumoniae
D. *Neisseria gonorrhoeae
E. Nocardia asteroides
15. In cervical specimens of 21-year-old woman presents gram-negative diplococci within leucocytes.
Which bacterium is most likely to be the cause of this infection?
A. Haemophilus influenzae
B. *Neisseria gonorrhoeae
C. Streptococcus pneumoniae
D. Staphylococcus aureus
E. Nocardia asteroides
16. A workman has a large pus-filled lesion on the left forearm, tender, red, and swollen. It is incised. A
smear of the pus is Gram-stained. Many neutrophils are seen, also many Gram-positive cocci, most in
large clusters. The organism is b-hemolytic on sheep blood agar. Colonies are pale-yellow, opaque, and
shiny, with neat round outlines. Of the bacteria listed below, which is most likely to have produced the
abscess?
A. Streptococcus bovis
B. Streptococcus pneumoniae
C. Streptococcus mitis
D. Enterococcus faecalis
E. *Staphylococcus aureus
17. A young man complaines on pain on urination and profuse purulent discharge from his urethra. Gram
stain of the discharge revealed large numbers Gram-negative cocci, mostly in pairs within neutrophils.
Which bacterium is most likely to have caused his infection?
A. Mycoplasma hominis
B. Chlamydia trachomatis
C. *Neisseria gonorrhoeae
D. Ureaplasma urealyticum
E. Treponema pallidum
18. A 17-year-old sexually-active male presents with a four-day history of pain on urination and profuse
purulent discharge from his urethral opening. Gram stain of the discharge revealed large numbers of
neutrophils. A small fraction of neutrophils contained Gram-negative cocci, mostly in pairs. Which
bacterium is most likely to have caused his infection?
A. Mycoplasma hominis
B. Chlamydia trachomatis
C. Treponema pallidum
D. Ureaplasma urealyticum
E. *Neisseria gonorrhoeae
19. An 18-year-old high school student has a large pus-filled lesion on the left forearm, tender, red, and
swollen. It is incised, drained, washed, and bandaged. A smear of the pus is Gram-stained. Many
neutrophils are seen, also many Gram-positive cocci, most in large clusters. The organism is bhemolytic on sheep blood agar. Colonies are pale-yellow, opaque, and shiny, with neat round outlines.
Of the bacteria listed below, which is most likely to have produced the abscess?
A. *Staphylococcus aureus
B. Streptococcus pneumoniae
C. Streptococcus mitis
D. Enterococcus faecalis
E. Streptococcus bovis
20. A post-surgical patient develops fever and there is redness and swelling around the surgical incision. A
day later pus begins to flow from the incision; Gram stain of pus shows large numbers of neutrophils
and many Gram-positive cocci, some in clusters. The organism is beta-hemolytic on blood agar, and is
coagulase- and catalase-positive. Which organism is most likely?
A. *Staphylococcus aureus
B. Staphylococcus epidermidis
C. Streptococcus pyogenes (Group A)
D. Streptococcus agalactiae (Group B)
E. Streptococcus pneumoniae
21. A child develops pneumonia. The bacterium Streptococcus pneumoniae is cultured from the patient’s
sputum. Cells of the cultured bacteria have thick polysaccharide capsules. How did the presence of
capsules promote development of serious disease?
A. Prevented binding of antibodies to the bacteria.
B. Prevented initiation of a humoral immune response.
C. Prevented activation of helper T cells.
D. *Prevented phagocytosis by neutrophils.
E. Prevented mast-cell degranulation.
22. An elderly man develops pneumonia and septicemia. Gram stain of sputum contains many neutrophils
and Gram-positive cocci, in pairs. Blood and sputum cultures grow out a Gram-positive coccus, ?hemolytic on sheep blood agar, and catalase-negative. Which organism below is most likely?
A. Staphylococcus epidermidis.
B. Staphylococcus aureus.
C. *Streptococcus pneumoniae.
D. Streptococcus pyogenes.
E. Streptococcus agalactiae.
23. Staphylococcus aureus is easily transmitted within the hospital environment. Which feature of this
bacterium is most largely responsible for its ease of spread?
A. *Resistance to heat, cold, and drying.
B. Ability to colonize the digestive tract.
C. Presence of an outer membrane impermeable to most disinfectants.
D. Production of extracellular polysaccharide which allows it to adhere tightly to surfaces.
E. Ability to form spores which are resistant to disinfectants and easily dispersed.
24. A 23-year-old medical student had headache and fever one evening. By the next morning she had
become very ill, with high fever, severe headache, and stiff neck. She was admitted to the hospital. Later
that day she developed rash, at first petechial and then pupuric. Gram stain of CSF showed many white
cells and Gram-negative cocci, many in pairs. Which organism is most likely to be the cause of her
infection?
A. Escherichia coli.
B. Haemophilus influenzae.
C. *Neisseria meningitidis.
D. Streptococcus agalactiae.
E. Streptococcus pneumoniae.
25. A patient has cellulitis of the left arm, persistent fever, and a heart murmur. He is a habitual user of
illegal drugs, which he self-administers intravenously. An echocardiogram shows a bacterial vegetation
on the aortic valve. Three blood cultures all grow an ?-hemolytic Gram-positive coccus,
catalasenegative. Which organism is most likely to have caused his infection?
A. Staphylococcus aureus.
B. *A Viridans-group Streptococcus.
C. Streptococcus pyogenes [Group A].
D. Streptococcus agalactiae [Group B].
E. Streptococcus bovis [Group D].
26. Untreated pharyngitis produced by Group A streptococci can result in later development of Acute
rheumatic fever, created by cross-reaction of anti-streptococcal antibodies with heart tissue. Which
streptococcal antigen stimulates formation of these cross-reactive antibodies?
A. A.Group A carbohydrate.
B. Flagella.
C. *M protein
D. Peptidoglycan.
E. Teichoic acid.
27. A neonate develops septicemia. Blood cultures produce a ?-hemolytic Gram-positive coccus. It is
catalase negative. Which test would best confirm the identity of the pathogen as a Group B
Streptococcus?
A. *Synergy of hemolysin with the hemolysin of Staphylococcus aureus [CAMP test].
B. Bile-esculin test.
C. Bacitracin sensitivity.
D. Optochin sensitivity.
E. Novobiocin sensitivity.
28. A individual may have repeated infections with Neisseria gonorrhoeae, despite the fact that each
infection gives rise to an immune response. By which mechanism does the gonococcus evade protective
immunity?
A. Thick capsule prevents binding of antibodies to the cell surface.
B. Pili adhere to epithelial cells despite binding of antibodies.
C. Capsular polysaccharide is identical to polysaccharides of mammalian cells.
D. Outer membrane lacks any antigenic components.
E. *The surface antigens present change continually, as a result of pre-programmed changes in
DNA.
29. An elderly resident of a nursing home develops pneumococcal pneumonia. This illness might have been
prevented had the patient been immunized against this organism. Which antigens of S. pneumoniae are
included in the adult vaccine?
A. M-proteins.
B. Intact heat-killed bacteria.
C. Toxoids produced from superantigen toxins.
D. *Capsular polysaccharides.
E. Cell-associated (C) carbohydrates.
30. Before the advent of immunization, outbreaks of meningococcal disease were frequent in military
camps. A factor in development of such outbreaks is the ability of Neisseria meningitidis to establish an
asymptomatic ‘carrier state’. What is the predominant site of carriage of Neisseria?
A. Urethral epithelium.
B. Gall bladder.
C. Large intestine.
D. *Nasopharynx.
E. Meninges and choroid plexus
31. A patient develops pneumonia caused by Streptococcus pneumoniae. The predominant virulence factor
of this organism is a thick capsule . Which phrase best describes the role of this capsule in virulence?
A. Aids in acquisition of iron.
B. Toxic to lung epithelial cells
C. Identical to human polysaccharide, so is non-immunogenic.
D. *Reduces phagocytosis by neutrophils.
E. Inhibits activation of Complement.
32. Two hours after a delicious Thanksgiving dinner of barley soup, roast turkey, stuffing, sweet potato,
green beans, cranberry sauce, and pump kin pie topped with whipped cream, the Smith family of four
experience vomiting and diarrhea. Which one of the following organisms is MOST likely to cause these
symptoms?
A. Shigella flexneri
B. Campylobacter jejuni
C. *Staphylococcus aureus
D. Salmonella enteritidis
E. All are true
33. An 81-year-old man with chronic emphysemea and hypertension develops fever, chills, and respiratory
distress. X-rays show lobar pneumonia. Sputum smear contains numerous Gram-positive cocci, many of
which are in pairs. Sputum culture on Sheep blood agar produces many colonies of an alpha-hemolytic
Gram-positive coccus. It is catalase-negative, Bile-esculin negative, and optochin-sensitive. Which of
the organisms below is most likely?
A. Streptococcus pyogenes (Group A)
B. Streptococcus agalactiae (Group B)
C. Streptococcus mitis
D. Streptococcus bovis (Group D)
E. *Streptococcus pneumoniae
34. A post-surgical patient develops redness around the incision and a day later pus begins to ooze from the
wound. Culture of a swab of pus produces beta-hemolytic colonies on Sheep blood agar. Gram stain
shows that the bacteria are Gram-positive cocci. Catalase and coagulase tests are positive. Which of the
following organisms is most likely?
A. Streptococcus pyogenes
B. Streptococcus agalactiae
C. Streptococcus mitis
D. *Staphylococcus aureus
E. Staphylococcus epidermidis
35. A 75-year-old man reports malaise, headache, and fever. On examination his neck is stiff. Gram stain of
CSF reveals neutrophils and numerous Gram-negative cocci, many in pairs.Which organism below is
most likely?
A. Pseudomonas aeruginosa
B. Klebsiella pneumoniae
C. Haemophilus influenzae
D. Neisseria gonorrhoeae
E. *Neisseria meningitidis
36. A 19-year-old man comes to your clinic because of thick purulent discharge from the urethral opening
of his penis. On Gram-stain of the discharge huge numbers of neutrophils are seen, a few of which
contain intracellular Gram-negative cocci. Many of the cocci are in pairs. What is the most likely
organism?
A. Neisseria meningitidis.
B. *Neisseria gonorrhoeae.
C. Haemophilus ducreyi.
D. Mycoplasma hominis.
E. Treponema pallidum.
37. A 35-year old patient got fever, nausea, vomiting and bloody diarrhea, all of the following bacteria
should be considered in the diffrential diagnosis, except one:
A. Salmonella
B. ETEC
C. Shigella
D. Yersinia
E. *Campylobacter
38. A 38 years old patient has chronic gastritis. Which of the following organisms is most likely?
A. Campylobacter fetus.
B. Escherichia coli.
C. A non-cholera Vibrio.
D. Campylobacter jejuni.
E. *Helicobacter pylori.
39. A 40-years-old patient has a peptic ulcer. Which organism is most likely to have created this lesion?
A. Campylobacter jejuni.
B. Enterococcus faecalis.
C. Escherichia coli.
D. Salmonella enteritidis
E. *Helicobacter pylori
40. A 5-years-old girl develops bloody diarrhea, produced by Shigella infection. From which source was
this infection most likely to have been contracted?
A. Rare hamburger.
B. Dog or cat.
C. Spores present in soil.
D. Cow, horse, or sheep.
E. *Another child.
41. A 6-year-old boy was brought to the emergency room with a history of bloody diarrhea over the
preceding two days. A fecal smear contained numerous red cells and neutrophils. Stool culture on Endo
agar produced lactose-negative colonies amid colonies of ‘normal intestinal flora’. Which of the
organisms below is most likely to be the cause of his illness?
A. Enteropathogenic E. coli
B. Balantidium coli.
C. Entamoeba histolytica
D. Giardia lamblia.
E. *Shigella.
42. A few healthy adult travelers visiting Peru are cautioned against eating uncooked vegetables and
unpeeled fruits, and against drinking unbottled water. However, they are already resistant to cholera
because of:
A. the gamma globulin shots they received before their trip.
B. their ability to avoid contaminated food due to its acidic smell.
C. they were vaccinated
D. their consumption of large prophylactic amounts of bicarbonates.
E. *a gastric barrier, due to stomach acids.
43. A four-year-old boy was brought to the emergency room with a history of bloody diarrhea over the
preceding two days. A fecal smear contained numerous red cells and neutrophils. Stool culture on Endo
agar produced lactose-negative colonies amid colonies of ‘normal intestinal flora’. Which of the
organisms below is most likely to be the cause of his illness?
A. Enteropathogenic E. coli
B. Balantidium coli.
C. Entamoeba histolytica
D. Giardia lamblia.
E. *Shigella.
44. A four-year-old boy was brought to the emergency room with a history of bloody diarrhea over the
preceding two days. A fecal smear contained numerous red cells and neutrophils. Stool culture on Endo
agar produced lactose-negative colonies amid colonies of ‘normal intestinal flora’. Which of the
organisms below is most likely to be the cause of his illness?
A. Enteropathogenic E. coli
B. Balantidium coli.
C. Entamoeba histolytica
D. Giardia lamblia.
E. *Shigella.
45. A microbiologist got a specimen from a patient with cholera. To determine to which species of vibrios
infectious agent belongs, the microbiologist performs some tests on colonies cultured from stool
samples. These tests include the following EXCEPT:
A. growth on thiosulfate-citrate-bile-sucrose (TCBS) agar
B. fermentation of sucrose
C. phagotyping
D. growth at different NaCl concentrations
E. *serotyping based on H antigens
46. A middle aged man recently returned from visiting his family in India develops severe diarrhea. He in
fact has cholera. His diarrhea is produced by a protein exotoxin secreted by Vibrio cholerae. How does
this toxin act?
A. ADP-ribosylates a chloride transporter.
B. Stimulates guanyl cyclase.
C. Inhibits guanyl cyclase.
D. Inhibits a G protein that inhibits adenyl cyclase.
E. *Stimulates a G protein that activates adenyl cyclase.
47. A patient got diarrhoea. The pathogenesis of which one of the following organisms is MOST likely to
involve invasion of the intestinal mucosa?
A. Enterotoxigenic Escherichia coli
B. Clostridium botulinum
C. Enteropathogenic Escherichia coli
D. Vibrio cholerae
E. *Shigella sonnei
48. A patient got severe diarrhoea. If this patient had Shigellosis, the stool culture on MacConkey agar will
grow:
A. glucose fermenting colonies
B. pink colonies
C. black colonies
D. lactose fermenting colonies
E. *non-lactose fermenting colonies
49. A patient has a peptic ulcer. Which organism is most likely to have created this lesion?
A. Campylobacter jejuni.
B. Enterococcus faecalis.
C. Salmonella enteritidis
D. Escherichia coli.
E. *Helicobacter pylori
50. A patient has been diagnosed with a gastric ulcer. A test of the patient's serum shows reactivity with
Helicobacter pylori antigens. Which of the following is true?
A. The patient's gastrin-hydrochloric homeostasis has been maintained.
B. Damage to the patient's gastric mucosa has been primarily caused by the patient's own immune
response.
C. All are true
D. The Helicobacter pylori infection most likely has nothing to do with the patient's condition.
E. *The patient will be treated with amoxicillin to eradicate H. pylori colonization and eliminate its
recurrence.
51. A patient has chronic gastritis. Which of the following organisms is most likely?
A. Escherichia coli.
B. A non-cholera Vibrio.
C. Campylobacter fetus.
D. Campylobacter jejuni.
E. *Helicobacter pylori.
52. A person got cholera. The best treatment for cholera is
A. tetracycline
B. toxoid
C. vaccine
D. antiserum injection
E. *rehydration therapy
53. A person got cholera. The large volume of fluid lost by diarrhea during infection with Vibrio cholerae
A. is a consequence of fluid replacement during treatment of the disease and does not result directly
from activity of the cholera toxin
B. results from electrolytes binding to the intestinal enterocytes which upsets their water retention
capability
C. results from neurotoxic effects of the cholera toxin on the central nervous system
D. is caused when the vibrios bind to the intestinal epithelium and physically or mechanically block
the uptake of fluids by the gut epithelial cells
E. *follows activation of adenylate cyclase by cholera toxin and the subsequent effect of cyclic
AMP on water and salt balances of the host cells
54. A young child develops bloody diarrhea, produced by Shigella infection. From which source was this
infection most likely to have been contracted?
A. Rare hamburger.
B. Spores present in soil.
C. Dog or cat.
D. Cow, horse, or sheep.
E. *Another child.
55. A young woman got cholera. The hallmark of therapy for severe cases of cholera is:
A. antimicrobial therapy
B. outpatient treatment
C. serotherapy
D. vaccination
E. *replacement of electrolytes
56. A young woman got cholera. To determine to which species the infectious agent belongs, the
microbiologist performs some tests on colonies cultured from stool samples. These tests include the
following EXCEPT:
A. growth on thiosulfate-citrate-bile-sucrose (TCBS) agar
B. serotyping based on O antigens
C. fermentation of sucrose
D. growth at different NaCl concentrations
E. *serotyping based on H antigens
57. Among the Sunday night patients at the Smithville emergency room were ten young adults suffering
from severe diarrhea. All are true individuals would normally characterize themselves as being in good
health. All reported eating at a local Dairy fair during the weekend. Of the following bacterial species
the least likely to be responsible is
A. Campylobacter fetus
B. Shigella flexneri
C. Campylobacter jejuni
D. Yersina enterocolitica
E. *Salmonella typhimurium
58. An engineer recently returned from visiting his family in India develops severe diarrhea. He in fact has
cholera. His diarrhea is produced by a protein exotoxin secreted by Vibrio cholerae. How does this toxin
act?
A. Stimulates guanyl cyclase.
B. Inhibits guanyl cyclase.
C. ADP-ribosylates a chloride transporter.
D. Inhibits a G protein that inhibits adenyl cyclase.
E. *Stimulates a G protein that activates adenyl cyclase.
59. From a 29-year-old stressed-out medical student with gastritis a urease-positive, spiral-shaped gramnegative rod is found in gastric washings. Which of the following is most likely to be this organism?
A. Proteus mirabilis
B. Providencia rettgeri
C. Vibrio cholerae
D. Campylobacter jejuni
E. *Helicobacter pylori
60. Gastroenteritis caused by Campylobacter jejuni is associated with consumption of contaminated water
or foods which include the following EXCEPT:
A. milk
B. poultry
C. chicken
D. clams
E. *hamburger
61. Gastroscopy reveals that a patient with stomach pain has a large ulceration of his gastric mucosa. During
the procedure a biopsy of the stomach epithelium is obtained. Which observation would suggest
Helicobacter pylori as the cause of illness?
A. Biopsy shows infiltration of gastric epithelium by lymphocytes.
B. pH of stomach fluid is equal to 1 (normal), rather than decreased.
C. Ingested isotope-labeled nitrate is converted to nitrite in the stomach.
D. Bacteria are found in stomach fluid, but not in contact with the gastric epithelium
E. *Curved or spiral bacteria are seen in the biopsy after silver staining.
62. Healthy adult travelers visiting Peru are cautioned against eating uncooked vegetables and unpeeled
fruits, and against drinking unbottled water. However, they are already resistant to cholera because of:
A. the gamma globulin shots they received before their trip.
B. their ability to avoid contaminated food due to its acidic smell.
C. their consumption of large prophylactic amounts of bicarbonates.
D. they were vaccinated
E. *a gastric barrier, due to stomach acids.
63. If this patient had Shigellosis, the stool culture on MacConkey agar will grow:
A. glucose fermenting colonies
B. pink colonies
C. black colonies
D. lactose fermenting colonies
E. *non-lactose fermenting colonies
64. In a 30-year old patient with fever, nausea, vomiting and bloody diarrhea, all of the following bacteria
should be considered in the diffrential diagnosis, except one:
A. Salmonella
B. Yersinia
C. ETEC
D. Shigella
E. *Campylobacter
65. Outbreaks of diarrhea caused by species of Shigella are common in day-care centers for children and
other similar settings. What property of Shigella most enhances its spread between children?
A. Frequent presence in the upper respiratory tracts of children who are not ill
B. Ability to ferment lactose and grow in refrigerated milk.
C. Possession of an envelope resistant to disinfectants.
D. Carriage by common classroom pets such as hamsters and gerbils
E. *Resistance to stomach acid and low infectious dose.
66. The microbiologist is aware that the gastroenteritis outbreak is associated with the consumption of raw
seafood at a local restaurant. She considers it may be due to a number of vibrios EXCEPT:
A. V. parahaemolyticus
B. V. alginolyticus
C. V. vulnificus
D. V. cholerae non 01
E. *V. fluvialis
F. *Dark-field microscopic observation of stool from infected patients reveals large nonmotile rods.
67. Your patient is a 30-year-old woman who was part of a tour group visiting a N. country. The day before
leaving, several members of the group developed fever, abdominal cramps, and bloody diarrhea. Of the
following, which one is the LEAST likely organism to cause this infection?
A. Salmonella enteritidis
B. Vibrio cholerae
C. Campylobacter jejuni
D. Staphylococcus aureus
E. *Shigella dysenteriae
68. Your patient is a 30-year-old woman who was part of a tour group visiting a N. country. The day before
leaving, several members of the group developed fever, abdominal cramps, and bloody diarrhea. Which
of the following bacterium is causative agent of dysenteriae?
A. Klebsiella
B. Proteus
C. E. coli
D. Vibrio
E. *Shigella
69. cholera. His diarrhea is produced by a protein exotoxin secreted by Vibrio cholerae. How does this toxin
act?
A. ADP-ribosylates a chloride transporter.
B. Inhibits a G protein that inhibits adenyl cyclase.
C. *Stimulates a G protein that activates adenyl cyclase.
D. Stimulates guanyl cyclase.
E. Inhibits guanyl cyclase.
70. A young child develops bloody diarrhea, produced by Shigella infection. From which source was this
infection most likely to have been contracted?
A. Rare hamburger.
B. Dog or cat.
C. Cow, horse, or sheep.
D. *Another child.
E. Spores present in soil.
71. Outbreaks of diarrhea caused by species of Shigella are common in day-care centers for children and
other similar settings. What property of Shigella most enhances its spread between children?
A. Frequent presence in the upper respiratory tracts of children who are not ill.
B. Ability to ferment lactose and grow in refrigerated milk.
C. Possession of an envelope resistant to disinfectants.
D. *Resistance to stomach acid and low infectious dose.
E. Carriage by common classroom pets such as hamsters and gerbils
72. A patient has chronic gastritis. Which of the following organisms is most likely?
A. Campylobacter fetus.
B. Campylobacter jejuni.
C. *Helicobacter pylori.
D. Escherichia coli.
E. A non-cholera Vibrio.
73. Gastroscopy reveals that a patient with stomach pain has a large ulceration of his gastric mucosa. During
the procedure a biopsy of the stomach epithelium is obtained. Which observation would suggest
Helicobacter pylori as the cause of illness?
A. *Curved or spiral bacteria are seen in the biopsy after silver staining.
B. Biopsy shows infiltration of gastric epithelium by lymphocytes.
C. pH of stomach fluid is equal to 1 (normal), rather than decreased.
D. Ingested isotope-labeled nitrate is converted to nitrite in the stomach.
E. Bacteria are found in stomach fluid, but not in contact with the gastric epithelium
74. to remove non-living bacterial components. Of those listed below, which is the most toxic?
A. *Lipopolysaccharide.
B. Polysaccharides of capsules.
C. Plasma-membrane lipids.
D. Proteins of the outer membrane.
E. Nucleic acids
75. A stool sample is plated on standard Endo-agar plates. After overnight incubation some of the colonies
are dark pink in color, others are pale, nearly colorless. What can you conclude about the bacteria that
produced dark-pink colonies?
A. Gram-positive.
B. *Ferment lactose.
C. Not likely to be ‘normal flora’.
D. Non-motile.
E. Produce capsules
76. A four-year-old boy was brought to the emergency room with a history of bloody diarrhea over the
preceding two days. A fecal smear contained numerous red cells and neutrophils. Stool culture on Endo
agar produced lactose-negative colonies amid colonies of ‘normal intestinal flora’. Which of the
organisms below is most likely to be the cause of his illness?
A. Enteropathogenic E. coli
B. Balantidium coli.
C. Entamoeba histolytica
D. Giardia lamblia.
E. *Shigella.
77. The severe diarrhea of cholera is produced by a protein exotoxin that acts on enterocytes. Which
statement below best describes the effect of Cholera toxin?
A. Alters the actin cytoskeleton.
B. Inactivates ribosomes.
C. Proteolytic cleavage of a specific cellular protein.
D. *Stimulates adenyl cyclase.
E. Stimulates guanyl cyclase.
78. A patient has a peptic ulcer. Which organism is most likely to have created this lesion?
A. Campylobacter jejuni.
B. Enterococcus faecalis.
C. Escherichia coli.
D. *Helicobacter pylori
E. Salmonella enteritidis
79. A 6 years old child has paroxysmal cough during 3 days. Whooping cough was diagnosed. What tested
material for examination is it needed to take first to confirm a diagnosis?
A. Patient’s blood
B. *Smear from the posterior wall of the throat
C. Pus
D. Patient’s serum
E. Vomiting masses
80. A baby was born in a maternity hospital. What vaccine is prescribed him before discharge from a
hospital?
A. Vaccine against whooping cough, diphtheria, and tetanus
B. Attenuated poliomyelitis vaccine
C. EV 76 vaccine
D. Attenuated influenza vaccine
E. *BCG
81. A child has a common cold which progresses to severe pharyngitis. Pharyngeal exudate forms a tough
membrane difficult to remove without causing bleeding. Culture of a throat swab on selective tellurite
agar produces abundant black colonies. Other cultures produce only normal flora. Which organism is
most likely to have caused this infection?
A. Actinomyces israelii.
B. Bordetella pertussis.
C. Candida albicans.
D. Mycobacterium avium/intracellulare.
E. *Corynebacterium diphtheriae.
82. A child has severe pharyngitis. Pharyngeal exudate forms a tough 'membrane', difficult to remove
without causing bleeding. Culture of a throat swab on selective tellurite agar produces abundant black
colonies. Other cultures produce only normal flora. Which organism below is most likely to have caused
this infection?
A. Streptococcus pneumoniae.
B. Haemophilus influenzae.
C. Bordetella pertussis.
D. Mycobacterium avium/intracellulare
E. *Corynebacterium diphtheriae.
83. A girl, 7 years of old was admitted to the hospital with the high temperature, throat pain general
weakness. A doctor suspected diphtheria and took material from pharynx for isolation of pure culture of
Corynebacterium. What test can confirm the diagnosis of diphtheria?
A. Examination of volutin granules
B. Examination of cystinase production
C. Examination of hemolytic properties
D. Susceptibility to phages
E. *Examination of bacterial toxigenicity
84. A growth of tuberculosis bacteria on nutrient media takes a place in 3 weeks, sometimes in 2-3 months.
But express technique for there cultivation, Prices and Shkolnikov’s methods may be used. In what time
is it possible to get growth of tuberculosis microcultures?
A. 3-4 days
B. 20-30 days
C. over 40 days
D. over 50 days
E. *7-10 days
85. A man, 40 years old has chronic kidneys infection. During examination of urine acids fast rod-shaped
microbes were revealed. They did not grow on simple nutrient media, but on Loewenstain-Jensen
medium in a few weeks they formed dry yellowish colonies. What group of microorganisms could cause
his disease?
A. Chlamidia
B. Mycoplasma
C. Trichomonas
D. Gardnerella
E. *Mycobacteria
86. A microbiologist put a few drops of 1% Ziehls phenol fuchsine on a paper which covers a smear from
patients sputum, heat it until steam rose. He repeated this procedure three times. Then took off a paper,
put a smear in 5 % sulphuric acid, washed with water and stained by methylene blue. What microbes
can be examined by this technique?
A. S. aureus
B. S. pneumoniae
C. S. viridans
D. K. pneumoniae
E. *M. tuberculosis
87. A mother with a 5 years old girl, who has a cough and flu-like state during 2 weeks, visited the doctor.
Last time a cough increased, paroxysmal cough appeared. A doctor diagnosed whooping-cough. What
factors do determine virulence of Bordetella pertussis?
F. Exotoxin
G. Pili
H. Hyaluronidaze
I. Histamin-sensitizing factor
J. *Thermolabile toxin
88. A patient has cough with discharges of sputum. During microscopic examination after staining this
smear by Ziehl-Neelsens technique dark blue cocci, which form irregular clasters and rod-shaped red
bacteria were revealed. What microorganisms may be a reason of disease?
A. Actinomyces bovis
B. Staphylococcus aureus
C. E.coli
D. Corynebacterium diphtheriae
E. *Mycobacterium tuberculosis
89. A sick child was tested by Mantouxs test. In 24 hours there were tumidity, hyperemia and painfulness in
the place of allergen injection. What basic mechanisms do provide this reaction of a body?
A. Granulocytes, T- lymphocytes, and Ig G.
B. Plasma cells, T-cell, and lymphokines
C. B-lymphocytes, IgM
D. Macrophages, B-lymphocytes, and monocytes
E. *Mononuclear cells, T-cell, and lymphokines
90. After making Mantouxs test in a child of 4 years old in 72 hours a reddening of the skin in the place of
injection of tuberculin is not observed. What does this result testify?
A. A child has tuberculosis
B. A child is vaccinated against tuberculosis
C. A child is a carrier of tuberculosis bacteria
D. A child is infected by tuberculosis bacteria
E. *A child is not vaccinated against tuberculosis
91. After staining of patient’s sputum by Ziehl-Neelsen technique red rod-shaped bacteria were revealed.
The first signs of bacterial growth appeared in 17 days. What bacteria may be there in the smear?
A. Yersinia pseudotuberculosis.
B. Histoplasma dubrosii
C. KlРµbsiella rhinoscleromanis
D. Coxiella burnetii
E. *Mycobacterium tuberculosis
92. After vaccination of babies by BCG vaccine immunity to tuberculosis lasts until there are living
bacteria of vaccine strain in an organism. What is correct name of such type of immunity?
A. Type specific
B. Humoral
C. Species inherited
D. Natural
E. *Non-sterile
93. Bacteriological laboratory urine from a patient with an initial diagnosis of kidneys tuberculosis must be
investigated in bacteriological laboratory. What method of diagnosis is it better to utilize?
A. Bacteriological
B. Bacterioscopy
C. Serological
D. Allergic
E. *Biological
94. 9 years old has diphtheria of pharynx. What was the way of diphtheria transmission?
A. Fecal-oral
B. *Air born
C. Sexual
D. Contact
E. No way
95. Diphtheria was diagnosed in 4 years old child. What preparation is it necessary to inject first of all?
A. TABTe.
B. Diphtherial toxoid
C. Vaccine against whooping cough, diphtheria, and tetanus
D. Vaccine against diphtheria and tetanus
E. *Diphtherial antiserum.
96. During examination of bacterial carriers in the kindergarten one nurse showed the presence of
Corynebacterium in her throat. The production of toxin by Corynebacterium diphtheriae was checked.
It did not produce exotoxin. What test was used for examination of toxigenicity?
A. Agglutination test
B. Ring precipitation test
C. *Precipitation test in gel
D. Complement fixation test
E. Immunofluorescence test
97. During examination of patient’s sputum, which was inoculated by Prices technique, rod-shaped bacteria
appear as plaits. What substance from tuberculosis bacilli does form such pictures?
A. Tuberculin.
B. *Cord-factor
C. Phtionic acid (phosphatide).
D. Fatty acids.
E. PPD.
98. During the examination child 6 years of old a doctor noticed greyish film on the surface of tonsils.
During the attempt of it’s deleting moderate bleeding appeared. During bacterioscopy after Neissers
staining: rods display club-shaped swellings, volutin granules. What symptoms will appear in a child in
the nearest days, if specific treatment will not be prescribed?
A. Oedema of lungs
B. *Toxic lesion of cardiac muscle and kidneys
C. Paroxysmal cough
D. Papular rashes on a skin
E. Disorders of digestion
99. Every year pediatricians use Mantouxs allergic for checking of the children and teenagers. What is the
aim of this test?
A. Treatment of tuberculosis
B. Prophylaxis of tuberculosis
C. Vaccination
D. *A selection of children for revaccination by BCG vaccine
E. No correct answer
100.
Five days old boy has planned immunization with BCG vaccine. In 7 years doctor prescribed
repeated immunization with the same vaccine. What examination was the basis of such doctor’s
decision?
A. Examination of antimycobacterial antibodies
B. *Skin allergic test
C. Medical and genetic examination
D. Bacterioscopy of childs sputum
E. X-ray examination of the lungs
101.
Five years old child was admitted to the hospital with a diagnosis of diphtheria of pharynx.
Material, which was taken from greyish film on tonsils, was inoculated Klaubergs medium. What are
there properties of Corynebacterium colonies on this medium?
A. Colonies are convex, with even edges, colorless
B. Colonies are rounded, concave in a center, white
C. Colonies are protuberant, viscid, remind a shagreen skin, grey
D. Colonies are rosette-like, a surface is knobby, yellow
E. *Colonies are grey, round, rosette-like
102.
In 6 years old child with paroxysmal cough mucous from oropharynx was taken. This material
was inoculated on glycerin-potatoes agar. In 72 hrs of cultivation at 37 C there were small greyish
convex, and glistening, resembling globules of mercury appeared. What causative agent did cause this
disease?
A. Haemophilus influenzae
B. Staphylococcus aureus
C. Neisseria meningitidis
D. *Bordetella pertussis
E. Mycobacteria tuberculosis
103.
In 8 years old child active tuberculosis process was suspected. Diagnostic Mantouxs reaction
was made. In 30 minutes after the injection there was an insignificant erubescence in the place of
injection. In 24 hours the phenomenon of dermahemia disappeared. What does the result of reaction
testify to?
A. Postvaccinal immunity
B. Active tubercular process.
C. *A reaction is negative
D. A tuberculosis process is occult
E. A reaction is positive
104.
In a 6 years old child active tuberculosis process was suspected. Diagnostic Mantouxs reaction
was made. What immunobiological preparation was used?
A. Pertussis-diphtheria-tetanus vaccine.
B. BCG vaccine.
C. *Tuberculin.
D. Tulyarin.
E. No correct answer
105.
In a child with the suspicion of diphtheria a swab from the mucus membrane of pharynx was
taken. After staining by Loeffers method dark-blue granules of volutin were revealed in bacteria. What
value does their examination have?
A. *Diagnostic
B. Treatment
C. Prophylactic
D. None of them
E. All answer are correct
106.
In a maternity hospital it follows newborn to execute an inoculation against tuberculosis. What
preparation must be here utilized?
A. Vaccine of EV.
B. Vaccine of STI
C. *Vaccine of BCZH
D. Vaccine of AKDP
E. Tuberculin
107.
In a smear from a patients tonsils with suspicion of diphtheria blue rod-shaped bacteria display
terminal club-shaped swellings, which stained more intensely at their end were revealed. What method
of staining was utilized?
A. Gram
B. Burry
C. Giemsa
D. *Loeffler
E. Neisser
108.
In an infectious department there is a girl, 10 years of old with a diagnosis diphtheria of
pharynx”. Toxigenic strain of Corynebacterium diphtheriae was isolated. How can you examine the
strain toxigenicity?
A. By agglutination test
B. By complement fixation test
C. *By precipitation test in a gel
D. By indirect haemagglutination test
E. By flocculation test
109.
In kindergarten whooping cough was diagnosed in 3 children. In what clinical periods of
whooping cough they may be most contagious?
A. Latent period
B. Paroxysmal period
C. *Catarrhal period
D. Regenerative period
E. Period of reconvalescence
110.
Patient has initial diagnosis of lung tuberculosis. What nutrient medium may be used for
isolation of mycobacteria:
A. glycerin-potatoes agar
B.
C.
D.
E.
*Loewenstein-Jensen medium
salt-salt agar
blood agar
Ploskirev medium
111.
Patients sputum was sent to a laboratory. What method of staining does it follow to utilize for the
examination of causative agents of tuberculosis?
A. Gram
B. Giemza-Romanovsky
C. Gins-Burry
D. *Ziehl-Neelsen
E. Neissers
112.
Seven years old child has fever and paroxysmal cough. Similar symptoms were observed in a
senior brother month ago. There may be whooping cough. What method is it possible to use for
retrospective diagnosis of this disease?
A. *Serological
B. Bacteriological
C. Biological
D. Morphological
E. Allergic
113.
The child has diagnosis of diphtheria of pharynx. The clinical diagnosis is confirmed by
bacteriologic examinations: toxigenic Corynebacterium diphtheria was isolated. What preparations do
apply for specific treatment?
A. Antibiotics
B. Sulfonamides
C. Toxoid
D. *Antitoxic serum
E. NO correct answer
114.
There is 7 years old child with a diagnosis of diphtheria of pharynx. What tested material must
be taken for isolation of causative agent and confirmation of diagnosis?
A. Patients blood
B. Patients serum
C. *Swab from the pharynx
D. Sputum
E. Pus
115.
There is a bacteriological method for laboratory diagnosis of diphtheria. For cultivation of РЎ.
diphtheriae it is necessary to know the some bacterial properties. What nutrient media it is necessary to
use for cultivation of Corynebacterium diphtheriae?
A. Serum agar
B. *blood agar, blood tellurite agar
C. sugar MPB, sugar MPA
D. yolk-salt agar
E. Endo, Ploskirev
116.
When doctor examined a child of 6 years old he revealed the greyish film on the tonsils. He took
this film, stained by Neisser's technique. What morphological feature was most substantial for
confirmation that these microbes are Corynebacteria?
A. Localization of microbes in macrophages
B. *The presence of volutin granules at the ends of microbes
C. Presence of spores, their diameter is more then diameter of the cell
D. Presence of flagella
E. Presence of capsule
117.
A patient is diagnosed with Clostridium difficile colitis. Which item would represent a known
risk factor for such infections?
A. *Been treated with antibiotics.
B. Consumed unpurified water.
C. Visited the southwestern United States.
D. Eaten undercooked fried rice.
E. Been in contact with livestock
118.
ANSWER:A
119.
A 22-year-old develops an abscess in his peritoneum following rupture of his appendix. Gram
stain of exudate from his foul-smelling abscess reveals numerous polymorphonuclear leukocytes, Grampositive cocci, Gram-positive rods, and Gram-negative rods. Aerobic culture of the exudate at 37oC on
blood and MacConkey agar yields only Enterococci. Which of the bacteria below is most likely to be
the Gram-negative rods seen in the stained smear?
A. Pseudomonas aeruginosa.
B. Proteus mirabilis.
C. Klebsiella pneumoniae.
D. Prevotella melaninogenica.
E. *Bacteroides fragilis.
120.
A 61-year-old diabetic man is admitted to the hospital for severe pain in his right leg; the
diagnosis is obstruction of the femoral artery. The affected area of the leg is painful, red, and swollen.
During the next 12 hours the swelling increases markedly, the skin of the leg becomes discolored, and
fluid-filled blisters appear on the skin. Gram stain of fluid aspirated from a blister reveals large Grampositive rods. Which organism below is most likely to have caused this infection?
A. Clostridium botulinum.
B. Clostridium difficile.
C. *Clostridium perfringens.
D. Clostridium tetani.
E. Listeria monocytogenes.
121.
The young man was injuring in car accident. The affected area of the leg is painful, red, and
swollen. During the next 12 hours the swelling increases markedly, the skin of the leg becomes
discolored, and fluid-filled blisters appear on the skin. Gram stain of fluid aspirated from a blister
reveals large Gram-positive rods. Which organism below is most likely to have caused this infection?
A. Clostridium botulinum.
B. *Clostridium perfringens.
C. Clostridium difficile.
D. Clostridium tetani.
E. Listeria monocytogenes.
122.
A child at-risk for Tetanus is treated with Tetanus immune globulin (human). What is a major
advantage of this method for immunization over the use of Tetanus toxoid?
A. Poses a reduced risk of serum sickness.
B. Provides longer-lasting immunity.
C. *Provides protection more rapidly.
D. Results in higher antibody titer.
E. Also provides secretory IgA for mucosal immunity.
123.
A child under treatment for leukemia is treated with Tetanus immune globulin (human). Which
phrase best describes the immunity that is produced?
A. Innate and specific.
B. Innate and humoral.
C. Innate and cell-mediated.
D. *Acquired and humoral.
E. Acquired and cell-mediated.
124.
A 20-year-old student has a deep laceration. He received the standard four-doses of DiphtheriaPertussis-Tetanus immunizations in infancy, and a booster at age 5, but has had no anti-Tetanus
immunization since. Which of the following would it be most appropriate to administer?
A. Tetanus toxoid.
B. Tetanus anti-toxin (equine).
C. Tetanus immune globulin (human).
D. *Both Tetanus toxoid and Tetanus immune globulin (human).
E. Both Tetanus toxoid Tetanus anti-toxin (equine).
125.
A ten-year-old girl has dirty, crushing, wounds, received when she fell from a motorcycle. She
has never been immunized against Tetanus. Which of the following should you administer?
A. Tetanus immune globulin (human) Tetanus toxoid
B. Tetanus anti-toxin (equine) Tetanus toxoid
C. Tetanus toxoid Tetanus immune globulin (human)
D. Tetanus toxoid plus Tetanus immune globulin (human),
E. *Tetanus toxoid plus Tetanus immune globulin (human
126.
A patient has rapidly spreading soft-tissue infection with gas in infected tissue. Fluid from a
blister contains many large Gram-positive rods which grow on sheep blood agar anaerobically but not
aerobically. Which pathogen is most consistent with these findings?
A. Bacillus anthracis.
B. Bacillus cereus.
C. Clostridium difficile.
D. *Clostridium perfringens.
E. Listeria monocytogenes.
127.
The spastic paralysis of Tetanus is the effect of a protein exotoxin. Which phrase below best
describes the process directly inhibited by Tetanus toxin?
A. Synthesis of neurotransmitter.
B. Transport of neurotransmitter into vesicles.
C. Calcium influx required for neurotransmitter release.
D. *Docking and fusion of neurotransmitter vesicles with the synaptic membrane.
E. Binding of neurotransmitter molecules to their receptors
128.
An infant is brought to the emergency room, cyanotic and with poor muscle tone. Which
condition is most likely given these findings?
A. Antibiotic-associated colitis.
B. Diphtheria.
C. Anthrax.
D. *Botulism.
E. Tetanus.
129.
A patient has an abscess from which Bacterioides fragilis is isolated. Which condition is most
likely to have facilitated infection by this organism?
A. Treatment with trimethoprim/sulfa.
B. *Tissue ischemia.
C. Presence of neutrophils.
D. Antibiotic treatment for another bacterial infection.
E. Colonization of the large intestine with spores of this organism.
B. A 50-year-old woman was treated for cystitis [caused by E. coli] with an oral broad-spectrum antibiotic.
Three weeks later she developed abdominal pain and diarrhea. A stained smear of stool contained many
neutrophils. Cultures for bacterial pathogens were negative. A serological test of stool for Clostridium
difficile toxin was positive. Which of the following is most likely to have been the immediately
predisposing cause of this patient’s C.difficile infection?
F. Colonization of her large intestine by antibiotic-resistant E. coli.
G. *Alteration of her intestinal flora by antibiotic treatment.
H. An allergic response to her antibiotic treatment.
I. Acquisition of an antibiotic-resistance plasmid (R-Factor) by C. difficile.
J. All are true
130.
Your patient is a 70-year-old man who under went bowel surgery for colon cancer 3 days ago.
He now has a fever and abdominal pain. You are concerned that he may have peritonitis. Which one of
the following pairs of organisms is MOST likely to be the cause?
A. *Bacteroides fragilis and Klebsiella pneumoniae
B. Bordetella pertussis and Salmonella enteritidis
C. Actinomyces israelii and Campylobacter jejuni
D. Clostridium botulinum and Shigella dysente-riae
E. All are true
131.
Five days ago a 65-year-old woman with a lower urinary tract infection began taking ampicillin.
She now has a fever and severe diarrhea. Of the organisms listed, which one is MOST likely to be the
cause of the diarrhea?
A. *Clostridium difficile
B. Bacteroides fragilis
C. Proteus mirabilis
D. Bordetella pertussis
E. All are true
132.
Laboratory assistant has to isolate Clostridium tetani, anaerobic sporeforming bacterium, from
wound exudation. What will he do before inoculation of material into appropriate culture medium?
A. he filtrates the material through cellulose filter
B. *he heats the sample to kill asporogenous bacteria at 800C for 20 min
C. wound discharge should be frozen before inoculation to inhibit facultative anaerobes
D. he will not do anything before investigation
E. he heats the sample to kill vegetative forms bacteria at 600C for 5 min
133.
Five days ago a 65-year-old woman with a lower urinary tract infection began taking ampicillin.
She now has a fever and severe diarrhea. Of the organisms listed, which one is MOST likely to be the
cause of the diarrhea?
A. *Clostridium difficile
B. Bacteroides fragilis
C. Proteus mirabilis
D. Bordetella pertussis
E. Clostridium tetani.
134.
A 55-year-old woman develops diplopia, one day after eating home-canned fruit. (Diplopia *
double vision, from inability to coordinate the direction of gaze of the eyes.) A few hours later she
develops difficulty speaking, bilateral weakness of her arms, nausea, vomiting, dizziness, blurred vision,
and dry mouth. However she is alert, oriented, and has no fever. If this is botulism, by what mechanism
did Clostridium botulinum produce her signs and symptoms?
A. Bound to Toll-like receptors and stimulated production of inflammatory cytokines.
B. Injected proteins into neurons via a type III secretion system.
C. *Secreted a protein toxin that enters mammalian neurons and blocks synaptic transmission.
D. Released peptidoglycan and other inflammatory components of the cell envelope.
E. Bacteremic spread followed by infection of multiple tissues: eyes, muscle, stomach, nervous
system, salivary glands.
135.
Home-canned food is a common source of botulism in adults. What property of C. botulinum
facilitates infection by this route?
A. *Produces airborne spores not easily killed by boiling.
B. Vegetative cells grow best at cooking temperatures.
C. Extremely resistant to gastric acid.
D. Thick peptidoglycan renders cells resistant to heat, cold, and drying.
E. Surface proteins inhibit digestive hydrolases.
136.
A patient has an abscess from which Bacterioides fragilis is isolated. Which condition is most
likely to have facilitated infection by this organism?
A. Treatment with trimethoprim/sulfa.
B. *Tissue ischemia.
C. Presence of neutrophils.
D. Antibiotic treatment for another bacterial infection.
E. Colonization of the large intestine with spores of this organism.
137.
A 61-year-old diabetic man is admitted to the hospital for severe pain in his right leg; the
diagnosis is obstruction of the femoral artery. The affected area of the leg is painful, red, and swollen.
During the next 12 hours the swelling increases markedly, the skin of the leg becomes discolored, and
fluid-filled blisters appear on the skin. Gram stain of fluid aspirated from a blister reveals large Grampositive rods. Which organism below is most likely to have caused this infection?
A. Clostridium botulinum.
B. Clostridium difficile.
C. *Clostridium perfringens.
D. Clostridium tetani.
E. Listeria monocytogenes.
138.
Surgeon has suspected anaerobic wound infection. To isolate causative germs collected wound
discharge should be cultivated into the such medium as :
A. Ploskirev agar
B. *Kitt-Tarozzi medium
C. meat peptone broth
D. Endo agar
E. meat peptone agar
139.
Laboratory assistant has to isolate Clostridia tetani, anaerobic sporeforming bacterium, from
wound exudation. What will he do before inoculation of material into appropriate culture medium?
A. he filtrates the material through cellulose filter
B. *he heats the sample to kill asporogenous bacteria at 800C for 20 min
C. wound discharge should be frozen before inoculation to inhibit facultative anaerobes
D. he will not do anything before investigation
E. he heats the sample to kill vegetative forms bacteria at 600C for 5 min
140.
Five days ago a 65-year-old woman with a lower urinary tract infection began taking ampicillin.
She now has a fever and severe diarrhea. Of the organisms listed, which one is MOST likely to be the
cause of the diarrhea?
A. *Clostridium difficile
B. Bacteroides fragilis
C. Proteus mirabilis
D. Bordetella pertussis
141.
A young man develops peritonitis following abdominal trauma. During surgery foul-smelling
purulent material is aspirated from the infected area. Gram stain of this material contains a mixture of
Grampositive cocci, Gram-positive rods, and many Gram-negative rods. Aerobic culture on sheep blood
agar yields many colonies of enterococci and a few colonies of E. coli; culture on MacConkey agar
produces only sparse colonies of E. coli. Anaerobic culture on sheep blood agar produces a few colonies
of beta-hemolytic Gram-positive rods and many colonies of slender Gram-negative rods. Which
organism is most likely to represent the majority of the Gram-negative rods seen when peritoneal
exudate was stained?
A. Yersinia enterocolitica
B. Clostridium perfringens
C. Clostridium tetani
D. Yersinia pseudotuberculosis
E. *Bacteroides fragilis
142.
A diabetic 78-year-old man develops a necrotic ulcer on his right foot. Infection spreads rapidly
and there is gas in soft tissues. His foot is amputated at the ankle. Gram stain of exudate from the
amputation site contains large Gram-positive rods. The bacteria grow well anaerobically, producing
large ?-hemolytic colonies on sheep blood agar, but do not grow aerobically. What organism is most
probable in this setting?
A. Bacillus cereus
B. Corynebacterium diphtheriae
C. Nocardia asteroides
D. Clostridium tetani
E. *Clostridium perfringens
143.
The spastic paralysis of Tetanus is the effect of a protein exotoxin. Which phrase below best
describes the process directly inhibited by Tetanus toxin?
A. Synthesis of neurotransmitter.
B. Transport of neurotransmitter into vesicles.
C. Calcium influx required for neurotransmitter release.
D. *Docking and fusion of neurotransmitter vesicles with the synaptic membrane.
E. Binding of neurotransmitter molecules to their receptors.
144.
A 50-year-old woman was treated for cystitis [caused by E. coli] with an oral broad-spectrum
antibiotic. Three weeks later she developed abdominal pain and diarrhea. A stained smear of stool
contained many neutrophils. Cultures for bacterial pathogens were negative. A serological test of stool
for Clostridium difficile toxin was positive. Which of the following is most likely to have been the
immediately predisposing cause of this patient’s C. difficile infection?
A. Colonization of her large intestine by antibiotic-resistant E. coli.
B. *Alteration of her intestinal flora by antibiotic treatment.
C. An allergic response to her antibiotic treatment.
D. Acquisition of an antibiotic-resistance plasmid (R-Factor) by C. difficile.
E. Binding of neurotransmitter molecules to their receptors
145.
A security guard at a New Jersey Court House comes to your office with a large lesion on his left
arm. It is 10 cm in diameter and ulcerated. Surrounding tissue is red and markedly swollen. The ulcer is
healing to produce a black scab. A swab of the ulcer contains large Gram-positive rods. After aerobic
culture on sheep blood agar these produce large alpha-hemolytic colonies. Which organism is most
likely?
A. *Bacillus anthracis
B. Bacillus cereus
C. Clostridium difficile
D. Clostridium perfingens
E. Clostridium tetani
146.
An infant is brought to the emergency room, cyanotic and with poor muscle tone. Which
condition is most likely given these findings?
A. Antibiotic-associated colitis.
B. Diphtheria.
C. Anthrax.
D. *Botulism.
E. Tetanus.
147.
In the United States human Tetanus is now a rare disease. Which measure below has been most
important in preventing it?
A. Vaccination of livestock, especially cattle, with a killed-organism vaccine.
B. *Immunization of humans with a toxoid-containing vaccine.
C. Eradication of the organism from the environment.
D. Sewage treatment and purification of water supplies.
E. Antibiotic treatment of contacts of patients with C. tetani infections.
148.
Water to be used for parenteral injection must sterilized to kill living microbes and then further
purified to remove non-living bacterial components. Of those listed below, which is the most toxic?
A. *Lipopolysaccharide.
B. Polysaccharides of capsules.
C. Plasma-membrane lipids.
D. Proteins of the outer membrane.
E. Nucleic acids
149.
A 13-year old boy develops pain and marked (10 cm.) swelling in his right inguinal lymph node
accompanied by fever of 104oF. He and his family have just returned from a vacation trip to Arizona
and New Mexico. Aspirate from the node contains Gram-negative rods. A direct immunofluorescent
assay on the aspirate provides a definitive diagnosis. The child is (successfully) treated with
streptomycin, and the aspirate is sent for culture to the CDC. Culture yields pale colonies on
MacConkey agar. What is the most probable pathogen?
A. *Yersinia pestis.
B. Helicobacteri pylori.
C. Franciscella tularensis.
D. Coxiella burnetii.
E. Klebsiella pneumoniae
150.
A 34-year old person has rapidly developing cough, dyspnoea, expectoration ana blood-tinged
sputum, he is febrile, cyanosed and toxic. Chest examination reveals crepitations and rhonchi. The most
likely diagnosis is
A. Legionella pneumonia
B. *Pneumonic plague
C. Septicaemic plague
D. Pulmory tuberculosis
E. No correct answer
151.
A doctor is struggling to diagnose a woman’s flulike illness. She complains of a fever that rises
during the day and peaks after dinner (undulant fever), fatigue, spinal tenderness, and loss of appetite.
Her lymph nodes are enlarged in physical exam. The doctor has trouble narrowing down the possible
etiologies until he hears that the tasted goat cheese at a French village a month before the onset of her
symptoms. Which of the following is the most likely cause?
A. Streptococcus pneumoniae
B. *Pseudomonas aeruginosa
C. Bordetella pertussis
D. Francisella tularensis
E. Brucella species
152.
A teenage girl enters the emergency room suffering painful muscle spasms. Throughout her
examination, she sustains a facial sneer, a stiff arched back, and clamped palms. Her father is anxious
about the fact that she has also experienced difficulty eating, probably due to a stiff jaw. The father
affirms that her daughter is usually quite active and boasts how, a week ago, she continued a soccer
game even after falling on a nail in the field. Which of the following is the most likely cause?
A. C. difficile
B. C. perfingens
C. C. septicum
D. C. botulinum
E. *C. tetani
153.
A woman straggles into the emergency room with a marked paralysis of her upper body. She
describes the paralysis as a weakness that began in her neck and spread to her arms. She also complains
of blurred double vision and requests water to soothe her dry throat. Though she has no fever, she
appears quite dizzy and her eyelids are drooping. The day before, she returned from a camping trip
where she insists she maintained good hygiene, limiting her diet to canned food only. Which of the
following is the most likely cause?
A. C. difficile
B. C. perfingens
C. C. septicum
D. *C. botulinum
E. C. tetani
154.
An old woman comes to the doctor with a fever and loose bowels. Her diarrhea occurs in
tremendous volumes, she complains, though she doesn’t remember seeing blood. She has an
unremarkable recent past medical history, except for an infection a few weeks earlier that was treated
with clindamycin. Sigmoidoscopy of her colon reveals yellow-white plaques which the doctor predicted
after analyzing her stools for toxins. Which of the following is the most likely cause?
A. *C. difficile
B. C. perfingens
C. C. septicum
D. C. botulinum
E. C. tetani
155.
A man enters the emergency room claiming to have been stabbed two days earlier. Muscles in
his arm hurt, and on palpation small air bubbles are felt below the skin. The wound area exudes a
blackish, ill-smelling fluid that generates a crackling sound when touched. The patient has a fever, a low
blood pressure, marked tachycardia, and urina very little since his injury. The doctor decides to
amputate the arm, as well as monitor the patient for shock and renal failure Which of the following is
the most likely cause?
A. C. difficile
B. *C. perfingens
C. C. septicum
D. C. botulinum
E. C. tetani
156.
A mother brings her 12-year-old son to your office because he has a skin lesion on his back. It is
20 cm in diameter, with a red inflamed border and a red center, with a paler ring between the red areas.
The mother says it has expanded rapidly over the last few days. Which of the following would be most
likely to cause such a lesion?
A. Rickettsia rickettsii
B. Treponema pallidum
C. *Borrelia burgdorferi
D. Chlamydia psittaci
E. Streptococcus pyogenes
157.
A 16-year-old boy has a skin lesion on his back. It is 20 cm in diameter, with a red inflamed
border and a red center, with a paler ring between the red areas. He says it has expanded rapidly over the
last few days after tick bite. Which of the following would be most likely to cause such a lesion?
A. Rickettsia rickettsii
B. *Borrelia burgdorferi
C. Treponema pallidum
D. Chlamydia psittaci
E. Streptococcus pyogenes
158.
A patient is diagnosed with pelvic inflammatory disease (PID), you suspect caused by
Chlamydia trachomatis. If you wished to confirm C. trachomatis, which test below should you use?
A. Culture of urine on broth-based agar at 20?C.
B. Culture of cervical exudate on chocolate agar in elevated CO2.
C. Microscopic examination of a stained smear of peripheral blood.
D. *Gram stain of exudate from the cervix.
E. PCR-based nucleic-acid amplification test of a cervical swab.
159.
You suspect Chlamydia infection in a sexually-active young woman. Which test would be most
likely to provide results which would confirm this diagnosis?
A. Agglutination test for anti-cardiolipin antibodies.
B. *PCR test of nucleic acids present in a urine sample.
C. Test of a blood sample for ‘cold agglutinins”.
D. Gram-stained smear of discharge from the cervix.
E. Culture of exudate from the cervix on Thayer-Martin agar.
160.
A mother is worried that the child may have contracted Lyme disease. Which finding would
most strongly suggest that she is correct?
A. A disseminated rash, with small papular erythematous lesions.
B. An ulcer and edema at the site of the tick bite.
C. A lesion at the site of the tick bite that develops a thick, black, crusted, scab.
D. *A “bull’s-eye” lesion with erythematous periphery and central clearing.
E. A sparse red macular rash, on the palms and soles only.
161.
A 25-year-old female presented with a three-day history of fever, headache and a non-productive
cough. X-rays show bilateral diffuse lung infiltrates. Culture of a throat swab (on sheep blood and
chocolate agars) revealed only “normal oral flora”. Penicillin G was prescribed and the patient sent
home. Her illness did not respond to this antibiotic. She was then successfully treated with
erythromycin. Which organism is most likely to have caused her illness?
A. *Mycoplasma pneumoniae.
B. Haemophilus influenzae.
C. Mycobacterium tuberculosis.
D. Streptococcus pyogenes.
E. Streptococcus pneumoniae.
162.
A patient has a positive Rapid Plasma Reagin (RPR) test for ‘non-treponemal antibodies’. A test
for specific anti-treponemal antibodies is positive but the patient has no rash, genital lesions,
inflammation, or discharge. Which conclusion best follows from these findings?
A. The patient does not require antibiotic treatment; absence of symptoms indicates that the positive
RPR is a ‘biological false positive”.
B. The patient has Syphilis, but does not require antibiotic treatment, because infections with
Treponema pallidum normally resolve spontaneously.
C. The patient has Syphilis, but the diagnosis should be confirmed by culture before
antibiotictreatment is started.
D. *The patient has Syphilis, and should be treated with Penicillin G
E. No correct answer
163.
In August, a young man presents with a history of fever for 1 week and a red rash which extends
to the palms and soles. IgM titer to Rickettsia rickettsii is 1:640. From which vector was this infection
most likely to have been acquired?
A. *Dog tick.
B. Mosquito of the genus Anopheles.
C. Blood-sucking sandfly.
D. Flea.
E. Human body louse.
164.
A 25-year-old man complains of a urethral discharge. You perform a Gram stain on a specimen
of the discharge and see neutrophils but no bacteria. Of the organisms listed, the one MOST likely to
cause the discharge is
A. Treponema pallidum
B. *Chlamydia trachomatis
C. Candida albicans
D. Coxiella burnetii
E. All are true
165.
An 8-year-old boy living in a wooded area of Virginia suddenly developed fever, headache, and
myalgia. On physical exam, a rash was noted on his limbs and trunk. Lesions of the rash were red and a
few mm in diameter. No organisms were isolated from several blood cultures. The child was treated
with tetracycline and recovered. Serological tests of acute and convalescent serum samples from the
child are most likely to reveal an increase in antibody titer to...
A. Borrelia burgdorferi.
B. Chlamydia pneumoniae.
C. Franciscella tularensis.
D. Yersinia pestis.
E. *Rickettsia rickettsii.
166.
A 15-year-old female presented with a three-day history of fever, headache and a non-productive
cough. Penicillin was prescribed and the patient was sent home. Her illness did not respond to this
antibiotic. Gram stain and culture of the patient's sputum and a throat swab revealed only 'normal oral
flora'. She was then successfully treated with erythromycin. Which organism below is most likely to
have caused her illness?
A. *Mycoplasma pneumoniae.
B. Haemophilus influenzae
C. Mycobacterium tuberculosis.
D. Corynebacterium diphtheriae.
E. Streptococcus pneumoniae.
167.
A farmer comes to the ER with a 1-week history of flu-like symptoms with photophobia. His
severe headache, cough, and myalgias suggest to the physician some kind of respiratory infection.
However, more careful physical exam reveals conjunctival suffusion and macular rash. Lab findings
include elevated serum bilirubin, alkaline phosphatase, aminotransferase, and creatine phosphokinase.
With this clinical picture and lab results, the physician prescribes penicillin G immediately. His
suspicions are confirmed later when a spirochete is isolated from the patient’s blood. Which of the
following is the most likely cause?
A. Treponema pallidum
B. *Leptospira interrogans
C. Borrelia burgdorferi
D. Borrelia recurrentis
E. Treponema vincentii
168.
Mycoplasma pneumoniae is a common cause of atypical pneumonia (walking pneumonia) and
chest x-ray often looks worse than symptoms suggest. Which of the following groups of people is the
most commonly affected?
A. Elderly
B. Middle-aged adults
C. *School-age children
D. Neonates
E. Pregnant mothers
169.
A 10-year-old boy in Virginia presents with a rash, fever, and severe headache that began several
days ago. The rash began on his palms and soles and has now spread to his trunk. His pediatrician also
notes conjunctival redness, and lab studies show proteinuria. The boy’s history is significant for a hike
in the woods a week ago. The child is given tetracycline and his diagnosis is confirmed by a Weil-Felix
test. Which of the following is the most likely cause?
A. Orientia tsutsugamushi
B. Coxiella burnetii
C. *Rickettsia rickettsii
D. Rickettsia prowazekii
E. Rickettsia acari
170.
A cattle farmer goes to the doctor complaining of mild cough and fever. He says that the fever
began abruptly several days ago. His occupation as cattle slaughterer leads the doctor towards a
diagnosis, and tetracycline is administered. The diagnosis is confirmed by serology and a negative WeilFelix test. Which of the following is the most likely cause?
A.
B.
C.
D.
E.
Orientia tsutsugamushi
*Coxiella burnetii
Rickettsia rickettsii
Rickettsia prowazekii
Rickettsia sibirica
171.
A Kosovo refugee sees a volunteer camp doctor complaining of a rash spreading outward from
his trunk but sparing his palms and soles. Two days ago, he experiences abrupt onset of fever,
headaches, and confusion. On physical exam, the doctor discovers lice in the man’s hair. The doctor
treats with a delousing regimen and tetracycline. Were he at a hospital, he might confirm the diagnosis
with a Weil-Felix test. Which of the following is the most likely cause?
A. Orientia tsutsugamushi
B. Coxiella burnetii
C. Rickettsia rickettsii
D. *Rickettsia prowazekii
E. Bartonella quintana
172.
A child develops pneumonia. The bacterium Streptococcus pneumoniae is cultured from the
patient’s sputum. Cells of the cultured bacteria have thick polysaccharide capsules. How did the
presence of capsules promote development of serious disease?
A. Prevented binding of antibodies to the bacteria.
B. Prevented initiation of a humoral immune response.
C. Prevented activation of helper T cells.
D. *Prevented phagocytosis by neutrophils.
E. Prevented mast-cell degranulation.
173.
Water to be used for parenteral injection must sterilized to kill living microbes and then further
purified to remove non-living bacterial components. Of those listed below, which is the most toxic?
A. *Lipopolysaccharide.
B. Polysaccharides of capsules.
C. Plasma-membrane lipids.
D. Proteins of the outer membrane.
E. Nucleic acids
174.
A child at-risk for Tetanus is treated with Tetanus immune globulin (human). What is a major
advantage of this method for immunization over the use of Tetanus toxoid?
A. Poses a reduced risk of serum sickness.
B. Provides longer-lasting immunity.
C. *Provides protection more rapidly.
D. Results in higher antibody titer.
E. Also provides secretory IgA for mucosal immunity.
175.
A child under treatment for leukemia is treated with Tetanus immune globulin (human). Which
phrase best describes the immunity that is produced?
A. Innate and specific.
B. Innate and humoral.
C. Innate and cell-mediated.
D. *Acquired and humoral.
E. Acquired and cell-mediated.
176.
An elderly man develops pneumonia and septicemia. Gram stain of sputum contains many
neutrophils and Gram-positive cocci, in pairs. Blood and sputum cultures grow out a Gram-positive
coccus, alpha-hemolytic on sheep blood agar, and catalase-negative. Which organism below is most
likely?
A. Staphylococcus epidermidis.
B. Staphylococcus aureus.
C. *Streptococcus pneumoniae.
D. Streptococcus pyogenes.
E. Streptococcus agalactiae.
177.
Staphylococcus aureus is easily transmitted within the hospital environment. Which feature of
this bacterium is most largely responsible for its ease of spread?
A. *Resistance to heat, cold, and drying.
B. Ability to colonize the digestive tract.
C. Presence of an outer membrane impermeable to most disinfectants.
D. Production of extracellular polysaccharide which allows it to adhere tightly to surfaces.
E. Ability to form spores which are resistant to disinfectants and easily dispersed.
178.
A stool sample is plated on standard Endo-agar plates. After overnight incubation some of the
colonies are dark pink in color, others are pale, nearly colorless. What can you conclude about the
bacteria that produced dark-pink colonies?
A. Gram-positive.
B. *Ferment lactose.
C. Not likely to be ‘normal flora’.
D. Non-motile.
E. Produce capsules.
179.
A 35-year-old woman presents with a history of increasing respiratory distress and cough
productive of sputum. Chest X-ray shows evidence of bilateral pneumonia. Cultures of blood and
sputum on Chocolate agar grow out slender Gram-negative rods; cultures on standard sheep blood agar
are negative. Which bacterium is most likely to be the cause of her infection?
A. Mycoplasma pneumoniae.
B. Chlamydia pneumoniae.
C. *Haemophilus influenzae.
D. Escherichia coli.
E. Streptococcus pneumoniae.
180.
You suspect Chlamydia infection in a sexually-active young woman. Which test would be most
likely to provide results which would confirm this diagnosis?
A. Agglutination test for anti-cardiolipin antibodies.
B. *PCR test of nucleic acids present in a urine sample.
C. Test of a blood sample for ‘cold agglutinins”.
D. Gram-stained smear of discharge from the cervix.
E. Culture of exudate from the cervix on Thayer-Martin agar.
181.
In the morning mss R. had become ill, with high fever, severe headache, and stiff neck. She was
admitted to the hospital. Later that day she developed rash, at first petechial and then pupuric. Gram
stain of CSF showed many white cells and Gram-negative cocci, many in pairs. Which organism is most
likely to be the cause of her infection?
A. Escherichia coli.
B. Haemophilus influenzae.
C. *Neisseria meningitidis.
D. Streptococcus agalactiae.
E. Streptococcus pneumoniae.
182.
A patient with septicemia goes into septic shock. Blood cultures later showed the pathogen to be
Escherichia coli. Which component of the bacteria was most likely to have produced shock?
A. Capsular polysaccharide.
B. Teichoic acid.
C. A superantigen toxin.
D. *Lipopolysaccharide [LPS].
E. Plasma membrane lipids.
183.
A patient has cellulitis of the left arm, persistent fever, and a heart murmur. He is a habitual user
of illegal drugs, which he self-administers intravenously. An echocardiogram shows a bacterial
vegetation on the aortic valve. Three blood cultures all grow an ?-hemolytic Gram-positive coccus,
catalasenegative. Which organism is most likely to have caused his infection?
A. Staphylococcus aureus.
B. *A Viridans-group Streptococcus.
C. Streptococcus pyogenes [Group A].
D. Streptococcus agalactiae [Group B].
E. Streptococcus bovis [Group D].
184.
Administration of which of the following vaccines would be contra-indicated in an patient with
impaired cell-mediated immunity?
A. Pneumococcal vaccine (pediatric).
B. Pneumococcal vaccine (adult).
C. *BCG vaccine against tuberculosis.
D. Tetanus toxoid.
E. Acellular Pertussis vaccine.
185.
A sexually-active woman develops a urinary tract infection which ascends to the kidneys. Blood
culture yields a ?-hemolytic Gram-negative rod. In this situation, which pathogen is most common?
A. *Escherichia coli.
B. Klebsiella pneumoniae.
C. Pseudomonas aeruginosa.
D. Salmonella enteritidis.
E. Serratia marcescens.
186.
A four-year-old boy was brought to the emergency room with a history of bloody diarrhea over
the preceding two days. A fecal smear contained numerous red cells and neutrophils. Stool culture on
Endo agar produced lactose-negative colonies amid colonies of ‘normal intestinal flora’. Which of the
organisms below is most likely to be the cause of his illness?
A. Enteropathogenic E. coli
B. Balantidium coli.
C. Entamoeba histolytica
D. Giardia lamblia.
E. *Shigella.
187.
A child develops a “cold” which progresses to severe pharyngitis. Pharyngeal exudate forms a
tough ‘membrane’, difficult to remove without causing bleeding. Culture of a throat swab on selective
tellurite agar produces abundant black colonies. Other cultures produce only normal flora. Which
organism is most likely to have caused this infection?
A. Actinomyces israelii.
B. Bordetella pertussis.
C. Candida albicans.
D. *Corynebacterium diphtheriae.
E. Mycobacterium avium/intracellulare.
188.
A patient has rapidly spreading soft-tissue infection with gas in infected tissue. Fluid from a
blister contains many large Gram-positive rods which grow on sheep blood agar anaerobically but not
aerobically. Which pathogen is most consistent with these findings?
A. Bacillus anthracis.
B. Bacillus cereus.
C. Clostridium difficile.
D. *Clostridium perfringens.
E. Listeria monocytogenes.
189.
Untreated pharyngitis produced by Group A streptococci can result in later development of
Acute rheumatic fever, created by cross-reaction of anti-streptococcal antibodies with heart tissue.
Which streptococcal antigen stimulates formation of these cross-reactive antibodies?
A. Group A carbohydrate.
B. Flagella.
C. *M protein
D. Peptidoglycan.
E. Teichoic acid.
190.
A child is diagnosed with Pertussis. How was this infection most likely to have been acquired?
A. Bite of a dog or cat.
B. Consumption of dairy products made from unpasteurized milk
C. Contact with livestock or animal products such as leather or wool.
D. *Inhalation of respiratory droplets of another human being.
E. Release of oral flora into the bloodstream by dental work
191.
Infections with Salmonella enterica, serotype typhi, spread throughout the body. A key to the
ability of serotype typhi to spread systemically is its ability to multiply intracellularly. Multiplication in
which cell type(s) is principally responsible for systemic spread?
A. *Monocytes/macrophages.
B. Basophils.
C. Enterocytes.
D. Erythrocytes.
E. Neutrophils.
192.
A 25-year-old female presented with a three-day history of fever, headache and a non-productive
cough. X-rays show bilateral diffuse lung infiltrates. Culture of a throat swab (on sheep blood and
chocolate agars) revealed only “normal oral flora”. Penicillin G was prescribed and the patient sent
home. Her illness did not respond to this antibiotic. She was then successfully treated with
erythromycin. Which organism is most likely to have caused her illness?
A. *Mycoplasma pneumoniae.
B. Haemophilus influenzae.
C. Mycobacterium tuberculosis.
D. Streptococcus pyogenes.
E. Streptococcus pneumoniae.
193.
A vacationer has “Traveler’s diarrhea” produced by enterotoxigenic E. coli. His profuse watery
diarrhea is produced by a protein exotoxin secreted by this bacterium. Which statement below best
describes the effect of this exotoxin?
A. Kills enterocytes and produces ulceration and inflammation.
B. Paralyzes phagocytosis by neutrophils.
C. *Stimulates ion transport by enterocytes into the intestinal lumen.
D. Blocks adsorption of nutrients by enterocytes.
E. Causes rearrangement of the enterocyte cytoskeleton and disappearance of the brush border.
194.
The severe diarrhea of cholera is produced by a protein exotoxin that acts on enterocytes. Which
statement below best describes the effect of Cholera toxin?
A. Alters the actin cytoskeleton.
B. Inactivates ribosomes.
C. Proteolytic cleavage of a specific cellular protein.
D. *Stimulates adenyl cyclase.
E. Stimulates guanyl cyclase.
195.
A neonate develops septicemia. Blood cultures produce a ?-hemolytic Gram-positive coccus. It
is catalase negative. Which test would best confirm the identity of the pathogen as a Group B
Streptococcus?
A. *Synergy of hemolysin with the hemolysin of Staphylococcus aureus [CAMP test].
B. Bile-esculin test.
C. Bacitracin sensitivity.
D. Optochin sensitivity.
E. Novobiocin sensitivity.
196.
A individual may have repeated infections with Neisseria gonorrhoeae, despite the fact that each
infection gives rise to an immune response. By which mechanism does the gonococcus evade protective
immunity?
A. Thick capsule prevents binding of antibodies to the cell surface.
B. Pili adhere to epithelial cells despite binding of antibodies.
C. Capsular polysaccharide is identical to polysaccharides of mammalian cells.
D. Outer membrane lacks any antigenic components.
E. *The surface antigens present change continually, as a result of pre-programmed changes in
DNA.
197.
A medical student with a three-week history of respiratory illness is treated with erythromycin [a
macrolide]. Which phrase best describes the process inhibited by this drug?
A. Transcription by bacterial RNA polymerase.
B. Supercoiling of bacterial DNA.
C. Cross-linking of peptidoglycan.
D. Polymerization of peptidoglycan.
E. *Peptide bond formation by bacterial ribosomes.
198.
An elderly resident of a nursing home develops pneumococcal pneumonia. This illness might
have been prevented had the patient been immunized against this organism. Which antigens of S.
pneumoniae are included in the adult vaccine?
A. M-proteins.
B. Intact heat-killed bacteria.
C. Toxoids produced from superantigen toxins.
D. *Capsular polysaccharides.
E. Cell-associated (C) carbohydrates.
199.
Before the advent of immunization, outbreaks of meningococcal disease were frequent in
military camps. A factor in development of such outbreaks is the ability of Neisseria meningitidis to
establish an asymptomatic ‘carrier state’. What is the predominant site of carriage of Neisseria?
A. Urethral epithelium.
B. Gall bladder.
C. Large intestine.
D. *Nasopharynx.
E. Meninges and choroid plexus
200.
Chlamydia trachomatis may be cultured on monolayers of human cells. If infected cells were
examined by staining and light microscopy, what would you be most likely to observe?
A. A membrane-bounded inclusion body, within the nucleus.
B. *A membrane-bounded inclusion body, within the cytoplasm.
C. Rod shaped Gram-positive bacilli, free within the cytoplasm.
D. Gram-negative cocci, within the lumen of the endoplasmic reticulum.
E. Cyst forms inside lysosomes.
201.
An infant is brought to the emergency room, cyanotic and with poor muscle tone.
202.
Which condition is most likely given these findings?
A. Antibiotic-associated colitis.
B. Diphtheria.
C. Anthrax.
D. *Botulism.
E. Tetanus.
203.
In what way do Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae
most closely resemble each other?
A. *Polysaccharide capsules.
B. Lipopolysaccharide in their outer membranes.
C. Teichoic acid in their envelopes.
D. Thick peptidoglycan in their cell walls.
E. Motility due to flagella.
204.
A patient becomes infected with Salmonella enterica serotype typhi. Which condition would
most strongly favor development of a “chronic carrier state” with this organism?
A. Age over 70 years.
B. Infection via the respiratory route.
C. *Gallstones.
D. Kidney stones.
E. Chronic pulmonary disease.
205.
A patient has an abscess from which Bacterioides fragilis is isolated. Which condition is most
likely to have facilitated infection by this organism?
A. Treatment with trimethoprim/sulfa.
B. *Tissue ischemia.
C. Presence of neutrophils.
D. Antibiotic treatment for another bacterial infection.
E. Colonization of the large intestine with spores of this organism.
206.
A patient develops pneumonia caused by Streptococcus pneumoniae. The predominant virulence
factor of this organism is a thick capsule . Which phrase best describes the role of this capsule in
virulence?
A. Aids in acquisition of iron.
B. Toxic to lung epithelial cells
C. Identical to human polysaccharide, so is non-immunogenic.
D. *Reduces phagocytosis by neutrophils.
E. Inhibits activation of Complement.
207.
A patient has a peptic ulcer. Which organism is most likely to have created this lesion?
A. Campylobacter jejuni.
B. Enterococcus faecalis.
C. Escherichia coli.
D. *Helicobacter pylori
E. Salmonella enteritidis.
208.
A 50-year-old woman was treated for cystitis [caused by E. coli] with an oral broad-spectrum
antibiotic. Three weeks later she developed abdominal pain and diarrhea. A stained smear of stool
contained many neutrophils. Cultures for bacterial pathogens were negative. A serological test of stool
for Clostridium difficile toxin was positive. Which of the following is most likely to have been the
immediately predisposing cause of this patient’s
G. difficile infection?
A. Colonization of her large intestine by antibiotic-resistant E. coli.
B. *Alteration of her intestinal flora by antibiotic treatment.
C. An allergic response to her antibiotic treatment.
D. Acquisition of an antibiotic-resistance plasmid (R-Factor) by C. difficile.
E. All are true
209.
A culture of skin lesions from a patient with pyoderma (impetigo) shows numerous colonies
surrounded by a zone of beta hemolysis on a blood agar plate. A Gram-stained smear shows grampositive cocci. If you found the catalase test to be negative, which one of the following organisms would
you MOST probably have isolated?
A. *Streptococcus pyogenes
B. Staphylococcus aureus
C. Staphylococcus epidermidis
D. Streptococcus pneumoniae
E. All are true
210.
Five hours after eating fried rice at a restaurant, a 24-year-old woman and her husband both
developed nausea, vomiting, and diarrhea. Which of the following organisms is the MOST likely to be
involved?
A. Clostridium perfringens
B. Enterotoxigenic Escherichia coli
C. *Bacillus cereus
D. Salmonella typhi
E. All are true
211.
Your patient is a 70-year-old man who underwent bowel surgery for colon cancer 3 days ago. He
now has a fever and abdominal pain. You are concerned that he may have peritonitis. Which one of the
following pairs of organisms is MOST likely to be the cause?
A. *Bacteroides fragilis and Klebsiella pneumoniae
B. Bordetella pertussis and Salmonella enteritidis
C. Actinomyces israelii and Campylobacter jejuni
D. Clostridium botulinum and Shigella dysente-riae
E. All are true
212.
A 65-year-old man develops dysuria and hematuria. A Gram stain of a urine sample shows
gram-negative rods. Culture of the urine on EMB agar reveals lactose-negative colonies without
evidence of swarming motility. Which one of the following organisms is MOST likely to be the cause of
his urinary tract infection?
A. Enterococcusfaecalis
B. *Pseudomonas aeruginosa
C. Proteus vulgaris
D. Escherichia coli
E. All are true
213.
A 25-year-old man complains of a urethral discharge. You perform a Gram stain on a specimen
of the discharge and see neutrophils but no bacteria. Of the organisms listed, the one MOST likely to
cause the discharge is
A. Treponema pallidum
B. *Chlamydia trachomatis
C. Candida albicans
D. Coxiella burnetii
E. All are true
214.
Two hours after a delicious Thanksgiving dinner of barley soup, roast turkey, stuffing, sweet
potato, green beans, cranberry sauce, and pumpkin pie topped with whipped cream, the Smith family of
four experience vomiting and diarrhea. Which one of the following organisms is MOST likely to cause
these symptoms?
A.
B.
C.
D.
E.
Shigella flexneri
Campylobacter jejuni
*Staphylococcus aureus
Salmonella enteritidis
All are true
215.
A 35-year-old woman presents with a history of increasing respiratory distress and cough
productive of sputum. Chest X-ray shows evidence of bilateral pneumonia. Cultures of blood and
sputum on Chocolate agar grow out slender Gram-negative rods; cultures on standard sheep blood agar
are negative. Which bacterium is most likely to be the cause of her infection?
A. Mycoplasma pneumoniae.
B. Chlamydia pneumoniae.
C. *Haemophilus influenzae.
D. Escherichia coli.
E. Streptococcus pneumonia
216.
A 15-year-old female presented with a three-day history of fever, headache and a non-productive
cough. Penicillin was prescribed and the patient was sent home. Her illness did not respond to this
antibiotic. Gram stain and culture of the patient's sputum and a throat swab revealed only 'normal oral
flora'. She was then successfully treated with erythromycin. Which organism below is most likely to
have caused her illness?
A. *Mycoplasma pneumoniae.
B. Haemophilus influenzae.
C. Mycobacterium tuberculosis.
D. Corynebacterium diphtheriae.
E. Streptococcus pneumoniae.
217.
An 81-year-old man with chronic emphysemea and hypertension develops fever, chills, and
respiratory distress. X-rays show lobar pneumonia. Sputum smear contains numerous Gram-positive
cocci, many of which are in pairs. Sputum culture on Sheep blood agar produces many colonies of an
alpha-hemolytic Gram-positive coccus. It is catalase-negative, Bile-esculin negative, and optochinsensitive. Which of the organisms below is most likely?
A. Streptococcus pyogenes (Group A)
B. Streptococcus agalactiae (Group B)
C. Streptococcus mitis
D. Streptococcus bovis (Group D)
E. *Streptococcus pneumoniae
218.
A post-surgical patient develops redness around the incision and a day later pus begins to ooze
from the wound. Culture of a swab of pus produces beta-hemolytic colonies on Sheep blood agar. Gram
stain shows that the bacteria are Gram-positive cocci. Catalase and coagulase tests are positive. Which
of the following organisms is most likely?
A. Streptococcus pyogenes
B. Streptococcus agalactiae
C. Streptococcus mitis
D. *Staphylococcus aureus
E. Staphylococcus epidermidis
219.
A young woman develops urgency, frequency, and dysuria. Two days later she develops fever,
chills, and costovertebral angle tenderness. Tests of urine for leukocyte esterase and nitrate reductase are
positive. Urine culture yields a beta-hemolytic Gram-negative rod which forms dark-pink colonies on
MacConkey agar. Which of the following organisms is most likely?
A. Pseudomonas aeruginosa
B. Klebsiellla pneumoniae
C. *Escherichia coli
D. Staphylococcus saprophyticus
E. Enterobacter, sp.
220.
A vacationer develops watery diarrhea but not chills or fever. In this setting which of the
following pathogens is the most common?
A. Salmonella enterica
B. *Escherichia coli
C. Staphylococcus aureus
D. Campylobacter jejuni
E. Helicobacter pylori
221.
A child develops a "cold" which progresses to severe pharyngitis. Pharyngeal exudate forms a
tough 'membrane', difficult to remove without causing bleeding. Culture of a throat swab on selective
tellurite agar produces abundant black colonies. Other cultures produce only normal flora. Which
organism below is most likely to have caused this infection?
A. Streptococcus pneumoniae.
B. Haemophilus influenzae.
C. *Corynebacterium diphtheriae.
D. Bordetella pertussis.
E. Mycobacterium avium/intracellulare.
222.
A burn patient develops infection of the burn wound. Culture of exudate on Brain-Heart Infusion
agar produces numerous green-pigmented colonies of a Gram-negative rod. The organism grows well
aerobically on standard media but shows no evidence of acid production on differential media such as
MacConkey, Hektoen Enteric, or Triple-Sugar-Iron agars.
223.
A 19-year-old man comes to your clinic because of thick purulent discharge from the urethral
opening of his penis. On Gram-stain of the discharge huge numbers of neutrophils are seen, a few of
which contain intracellular Gram-negative cocci. Many of the cocci are in pairs. What is the most likely
organism?
A. Neisseria meningitidis.
B. *Neisseria gonorrhoeae.
C. Haemophilus ducreyi.
D. Mycoplasma hominis.
E. Treponema pallidum
224.
An elderly man develops pneumonia and septicemia. Gram stain of sputum contains many
neutrophils and Gram-positive cocci, in pairs. Blood and sputum cultures grow out a Gram-positive
coccus, alpha-hemolytic on sheep blood agar, and catalase-negative. Which organism below is most
likely?
A. Staphylococcus epidermidis
B. Staphylococcus aureus
C. *Streptococcus pneumoniae
D. Streptococcus pyogenes
E. Streptococcus agalactiae
225.
A post-surgical patient develops fever and there is redness and swelling around the surgical
incision. A day later pus begins to flow from the incision; Gram stain of pus shows large numbers of
neutrophils and many Gram-positive cocci, some in clusters. The organism is beta-hemolytic on blood
agar, and is coagulase- and catalase-positive. Which organism is most likely?
A. *Staphylococcus aureus
B. Staphylococcus epidermidis
C. Streptococcus pyogenes (Group A)
D. Streptococcus agalactiae (Group B)
E. Streptococcus pneumoniae
226.
A patient presented with upper back pain. MRI imaging demonstrated inflammation of the T8T9 vertebral bodies consistent with osteomyelitis. A bone marrow biopsy, when cultured, produced
colonies of Gram-positive cocci.Colonies on Sheep blood agar were 3-4 mm in diameter, off-white and
beta-hemolytic. Colonies on Brain-heart infusion (BHI) agar were 2-3 mm in diameter and goldenyellow. Catalase and coagulase tests were positive. What was the most likely pathogen?
A. *Staphylococcus aureus
B. Staphylococcus epidermidis
C. Streptococcus pyogenes
D. Streptococcus pneumoniae
E. Streptococcus mitis
227.
A 20-year-old women presents at a local clinic with fever and abdominal tenderness. She reports
having had unprotected sexual intercourse a few weeks earlier. Gram-negative diplococci are seen in a
Gram stain of vaginal secretions; many of the bacteria are inside polymorphonuclear leukocytes. Which
virulence factor is most important in aiding this bacterium to initiate infection?
A. Ability to invade cells.
B.
C.
D.
E.
*Adhesive pili.
Anti-phagocytic capsule.
Endotoxin.
Flagella.
228.
A 23-year-old medical student had headache and fever one evening. By the next morning she had
become very ill, with high fever, severe headache, and stiff neck. She was admitted to the hospital. Later
that day she developed rash, first petechial and then pupuric. Her white count was 26,000/ull, with 80%
neutrophils and 10% 'bands'. Gram stain ofCSF showed many white cells and numerous bacteria. If the
pathogen is Neisseria meningitidis, how would you expect it to appear on Gram stain?
A. Gram-positive cocci, many in pairs.
B. Gram-positive cocci, many in clusters.
C. Isolated Gram-positive cocci.
D. *Gram-negative cocci, many in pairs.
E. Gram-negative cocci, many in clusters.
229.
A vacationing couple both develop severe watery diarrhea which lasts three days. Which
organism is the most common etiologic agent of such infections?
A. Shigella sonnei.
B. Pseudomonas aeruginosa.
C. Salmonella typhi.
D. Campylobacter jejuni.
E. *Escherichia coli.
230.
Several medical students go to Cancun over spring break. One evening, at a local bar, they drink
several pitchers of Margaritas made with crushed ice. They spend the next two days in their hotel room
with severe watery diarrhea, but no chills or fever. By the third day they recover completely. Which
organism is most likely to have been the cause of their illness?
A. Non-typhoidal Salmonella.
B. Helicobacter pylori.
C. Campylobacter jejuni.
D. *Enterotoxigenic E. coli.
E. Non-cholera Vibrio.
231.
A sexually-active woman develops a urinary tract infection which ascends to the kidneys
(pyelonephritis). Blood culture yields a beta-hemolytic Gram-negative rod. In this situation, which
pathogen below is most common?
A. Salmonella enteritidis.
B. Pseudomonas aeruginosa.
C. Serratia marcescens.
D. Klebsiella pneumoniae.
E. *Escherichia coli.
232.
23-year-old woman comes to your office because, for 3 days, she has experienced burning with
urination, increased frequency of urination, and a continual feeling that she needs to urinate. She does
not have vaginal discharge, fever, or flank pain. Rapid 'dipstick' urine tests are consistent with
uncomplicated cystitis. Culture of urine on standard media produces a lactose-fermenting Gramnegative rod. In situations such as this, what is the most likely pathogen?
A. Enterobacter faecium
B. *Escherichia coli
C. Klebsiella pneumoniae
D. Proteus vulgaris
E. Pseudomonas aeruginosa
233.
A patient has chronic gastritis. Which of the following organisms is most likely?
A. Campylobacter fetus.
B. Campylobacter jejuni.
C. *Helicobacter pylori.
D. Escherichia coli.
E. A non-cholera Vibrio.
234.
Gastroscopy reveals that a patient with stomach pain has a large ulceration of his gastric mucosa.
During the procedure a biopsy of the stomach epithelium is obtained.
235.
Which observation would suggest Helicobacter pylori as the cause of illness?
A.
B.
C.
D.
E.
*Curved or spiral bacteria are seen in the biopsy after silver staining.
Biopsy shows infiltration of gastric epithelium by lymphocytes.
pH of stomach fluid is equal to 1 (normal), rather than decreased.
Ingested isotope-labeled nitrate is converted to nitrite in the stomach.
Bacteria are found in stomach fluid, but not in contact with the gastric epithelium
236.
A child has Pertussis. How was this infection most likely to have been acquired?
A. Release of oral flora into the bloodstream by dental work.
B. Bite of a dog or cat.
C. Contact with livestock, or animal products such as leather or wool.
D. Consumption of dairy products made from unpasteurized milk
E. *Inhalation of respiratory droplets from another person.
237.
A patient is diagnosed with Clostridium difficile colitis. Which item would represent a known
risk factor for such infections?
A. *Been treated with antibiotics.
B. Consumed unpurified water.
C. Visited the southwestern United States.
D. Eaten undercooked fried rice.
E. Been in contact with livestock
238.
A 22-year-old develops an abscess in his peritoneum following rupture of his appendix. Gram
stain of exudate from his foul-smelling abscess reveals numerous polymorphonuclear leukocytes, Grampositive cocci, Gram-positive rods, and Gram-negative rods. Aerobic culture of the exudate at 37oC on
blood and MacConkey agar yields only Enterococci.Which of the bacteria below is most likely to be the
Gram-negative rods seen in the stained smear?
A. Pseudomonas aeruginosa.
B. Proteus mirabilis.
C. Klebsiella pneumoniae.
D. Prevotella melaninogenica.
E. *Bacteroides fragilis.
239.
The young man was injuring in car accident. The affected area of the leg is painful, red, and
swollen. During the next 12 hours the swelling increases markedly, the skin of the leg becomes
discolored, and fluid-filled blisters appear on the skin. Gram stain of fluid aspirated from a blister
reveals large Gram-positive rods. Which organism below is most likely to have caused this infection?
A. Clostridium botulinum.
B. *Clostridium perfringens.
C. Clostridium difficile.
D. Clostridium tetani.
E. Listeria monocytogenes.
240.
A patient has endocarditis produced by an alpha-hemolytic Streptococcus. This usually reflects
spread of normal flora to the bloodstream. From which site is this isolate most likely to have spread?
A. Anterior nares.
B. Facial skin.
C. Lower respiratory tract.
D. Distal urethra.
E. *Oropharynx
241.
A five-day-old child develops high fever and stiff neck. A spinal tap is performed. A Gramstained smear of cerebrospinal fluid reveals many neutrophils and short, thick, Gram-negative rods of
uniform length. This microbes can ferment lactose.Which organism below is most likely to have caused
this infection?
A. *Escherichia coli
B. Haemophilus influenzae
C. Streptococcus pneumoniae
D. Neisseria meningitidis
E. Streptococcus agalactiae
242.
A nine years-old child develops high fever and stiff neck. A spinal tap is performed. A Gramstained smear of cerebrospinal fluid reveals many neutrophils and Gram-negative cocci that resemble
paired kidney beans within leucocytes. Which organism below is most likely to have caused this
infection?
A.
B.
C.
D.
E.
Escherichia coli
Haemophilus influenzae
Listeria monocytogenes
*Neisseria meningitidis
Streptococcus agalactiae
243.
Gram stain of CSF sediment from a patient with meningitis contains Gram-negative cocci, many
in pairs. Which organism below is most likely?
A. Streptococcus pneumoniae
B. Haemophilus influenzae
C. *Neisseria meningitidis
D. Pseudomonas aeruginosa
E. Escherichia coli
244.
Which test below would best distinguish S. aureus from one of the less-virulent staphylococci?
A. Production of catalase.
B. Colony color when grown on BHI agar.
C. Ability to grow on MacConkey agar.
D. *Production of coagulase.
E. Type of hemolysis on sheep blood agar.
245.
The laboratory informs you that an isolate of Staphylococcus aureus is ‘methicillin-resistant’.
Which phrase below best describes such isolates?
A. Although resistant to methicillin, nearly all are sensitive to cephalosporins.
B. *They are resistant to both ‘anti-staph’ penicillins and cephalosporins.
C. They are seldom resistant to antibiotics other than ?-lactams.
D. They produce a ?-lactamase active on both cephalosporins and penicillins.
E. The ‘methicillin-resistance’ gene also confers resistance to vancomycin.
246.
A young man has a large pus-filled abscess on his upper arm but does not go to a doctor. Several
days later he is brought to the Emergency Room with fever, hypotension, and multiple organ failure.
Which of the following is most likely to be responsible?
A. Streptococcus pyogenes Erythrogenic toxin.
B. Clostridium perfringens ?-toxin.
C. *Staphylococcus aureus Toxic Shock Syndrome Toxin-1.
D. Shigella dysenteriae Shiga Toxin.
E. Escherichia coli Heat-labile Toxin (ST).
247.
Members of a family suffer acute attacks of nausea and vomiting a few hours after returning
from a daylong picnic, at which they ate hamburgers, potato salad, and custard pie. By morning all are
feeling better. Which bacterial toxin is most likely to have caused their symptoms?
A. Clostridium difficile Cytotoxin.
B. Escherichia coli Labile Toxin
C. Escherichia coli Stable Toxin.
D. *Staphylococcus aureus Enterotoxin.
E. Helicobacteri pylori Cytotoxin.
248.
A patient with Cystic fibrosis develops pneumonia. A Gram-negative rod is cultured from her
respiratory tract. On nutrient-poor media it grows well and secretes large amounts of bright green
pigment. It produces acid from none of the sugars on which it was tested (including lactose and
sucrose). Which organism below is most likely?
A. Shigella sonnei
B. Salmonella typhi
C. *Pseudomonas aeruginosa
D. Escherichia coli
E. Klebsiella pneumoniae
249.
Bacteroides fragilis is isolated from an abdominal abscess. Which phrase below best describes
infections like this one?
A. *Other species of bacteria are also often present.
B. Initiated by ingestion of spores.
C. Can be successfully treated with aminoglycosides alone.
D. Contracted by the respiratory route.
E. Sexually-transmitted
250.
A young woman has a urinary tract infection caused by E. coli. By what route are such infections
most commonly acquired?
A. Respiratory route, followed by spread from the anterior nares.
B. Respiratory route, followed by spread from the oro-pharyngeal region.
C. *Fecal-oral route, followed by colonization of the intestine and then the perineum.
D. Intestinal infection, followed by spread of bacteria to the urethra via the bloodstream.
E. Direct contact route
251.
A 35-year old patient got fever, nausea, vomiting and bloody diarrhea, all of the following
bacteria should be considered in the diffrential diagnosis, except one:
A. Salmonella
B. ETEC
C. Shigella
D. Yersinia
E. *Campylobacter
252.
A 38 years old patient has chronic gastritis. Which of the following organisms is most likely?
A. Campylobacter fetus.
B. Escherichia coli.
C. A non-cholera Vibrio.
D. Campylobacter jejuni.
E. *Helicobacter pylori.
253.
A 40-years-old patient has a peptic ulcer. Which organism is most likely to have created this
lesion?
A. Campylobacter jejuni.
B. Enterococcus faecalis.
C. Escherichia coli.
D. Salmonella enteritidis
E. *Helicobacter pylori
254.
A 5-years-old girl develops bloody diarrhea, produced by Shigella infection. From which source
was this infection most likely to have been contracted?
A. Rare hamburger.
B. Dog or cat.
C. Spores present in soil.
D. Cow, horse, or sheep.
E. *Another child.
255.
A 6-year-old boy was brought to the emergency room with a history of bloody diarrhea over the
preceding two days. A fecal smear contained numerous red cells and neutrophils. Stool culture on Endo
agar produced lactose-negative colonies amid colonies of ‘normal intestinal flora’. Which of the
organisms below is most likely to be the cause of his illness?
A. Enteropathogenic E. coli
B. Balantidium coli.
C. Entamoeba histolytica
D. Giardia lamblia.
E. *Shigella.
256.
A few healthy adult travelers visiting Peru are cautioned against eating uncooked vegetables and
unpeeled fruits, and against drinking unbottled water. However, they are already resistant to cholera
because of:
A. the gamma globulin shots they received before their trip.
B. their ability to avoid contaminated food due to its acidic smell.
C. they were vaccinated
D. their consumption of large prophylactic amounts of bicarbonates.
E. *a gastric barrier, due to stomach acids.
257.
A four-year-old boy was brought to the emergency room with a history of bloody diarrhea over
the preceding two days. A fecal smear contained numerous red cells and neutrophils. Stool culture on
Endo agar produced lactose-negative colonies amid colonies of ‘normal intestinal flora’. Which of the
organisms below is most likely to be the cause of his illness?
A. Enteropathogenic E. coli
B. Balantidium coli.
C. Entamoeba histolytica
D. D.Giardia lamblia.
E. *Shigella.
258.
A four-year-old boy was brought to the emergency room with a history of bloody diarrhea over
the preceding two days. A fecal smear contained numerous red cells and neutrophils. Stool culture on
Endo agar produced lactose-negative colonies amid colonies of ‘normal intestinal flora’. Which of the
organisms below is most likely to be the cause of his illness?
A. Enteropathogenic E. coli
B. Balantidium coli.
C. Entamoeba histolytica
D. Giardia lamblia.
E. *Shigella.
259.
A laboratory got a sample from a patient with cholera. Which of the following tests would not
differentiate Vibrio cholera non O1 from Vibrio parahaemolyticus?
A. oxidase activity.
B. Growth on special blood agar
C. Production of enterotoxin
D. Growth on salt-free and salt-containing agar.
E. *Growth on TCBS agar
260.
A laboratory got a sample from a patient with cholera. Which of the following is not true about
the bacterium classified as Vibrio cholerae (V. cholerae О1):
A. causes disease only through the production of an enterotoxin
B. reacts with group 1 antiserum against the lipopolysaccharide (О) antigens
C. arabinose is not fermented
D. invades the small intestine
E. *is often associated with marine environments
261.
A laboratory got a sample from a patient with diarrhoea. Which of the following media is an
enrichment medium for the isolation of Shigella?
A. Tetrathionate broth.
B. Alkaline peptone water.
C. Taurocholate peptone transport and enrichment medium.
D. Endo medium
E. *Selenite F broth.
262.
A laboratory got a sample from a patient with diarrhoea. Cholera toxin resembles which of the
following toxins?
A. Stable toxin of E. coli.
B. Diphtheria toxin.
C. Tetanus toxin.
D. Staphylococcus enterotoxin
E. *Labile toxin of Escherichia coli.
263.
A laboratory got a sample from a patient with diarrhoea. To test a stool specimen for
Campylobacter, all of the following measures would be used except:
A. Plating on agar containing glucose or sucrose
B. Plating on Campy blood agar containing 5 antibiotics
C. Incubating the plates in an atmosphere of 5% O2, 10% CO2
D. Incubating the plates at 42° C
E. *Passing the samples through 0.45 micron filters
264.
A microbiologist got a sample from a patient with cholera. Which of the following statements is
true about the toxin produced by Vibrio cholera?
A. The B subunit directly stimulates the host adenylate cyclase.
B. The toxin blocks the host adenylate cyclase.
C. The toxin is lypopolisaccharide
D. It has its own adenylate cyclase activity.
E. *The A1 subunit indirectly stimulates the host adenylate cyclase.
265.
A microbiologist got a specimen from a patient with cholera. To determine to which species of
vibrios infectious agent belongs, the microbiologist performs some tests on colonies cultured from stool
samples. These tests include the following EXCEPT:
A.
B.
C.
D.
E.
growth on thiosulfate-citrate-bile-sucrose (TCBS) agar
fermentation of sucrose
phagotyping
growth at different NaCl concentrations
*serotyping based on H antigens
266.
A middle aged man recently returned from visiting his family in India develops severe diarrhea.
He in fact has cholera. His diarrhea is produced by a protein exotoxin secreted by Vibrio cholerae. How
does this toxin act?
A. ADP-ribosylates a chloride transporter.
B. Stimulates guanyl cyclase.
C. Inhibits guanyl cyclase.
D. Inhibits a G protein that inhibits adenyl cyclase.
E. *Stimulates a G protein that activates adenyl cyclase.
267.
A patient got diarrhoea. The pathogenesis of which one of the following organisms is MOST
likely to involve invasion of the intestinal mucosa?
A. Enterotoxigenic Escherichia coli
B. Clostridium botulinum
C. Enteropathogenic Escherichia coli
D. Vibrio cholerae
E. *Shigella sonnei
268.
A patient got severe diarrhoea. If this patient had Shigellosis, the stool culture on MacConkey
agar will grow:
A. glucose fermenting colonies
B. pink colonies
C. black colonies
D. lactose fermenting colonies
E. *non-lactose fermenting colonies
269.
A patient has a peptic ulcer. Which organism is most likely to have created this lesion?
A. Campylobacter jejuni.
B. Enterococcus faecalis.
C. Salmonella enteritidis
D. Escherichia coli.
E. *Helicobacter pylori
270.
A patient has been diagnosed with a gastric ulcer. A test of the patient's serum shows reactivity
with Helicobacter pylori antigens. Which of the following is true?
A. The patient's gastrin-hydrochloric homeostasis has been maintained.
B. Damage to the patient's gastric mucosa has been primarily caused by the patient's own immune
response.
C. All are true
D. The Helicobacter pylori infection most likely has nothing to do with the patient's condition.
E. *The patient will be treated with amoxicillin to eradicate H. pylori colonization and eliminate its
recurrence.
271.
A patient has chronic gastritis. Which of the following organisms is most likely?
A. Escherichia coli.
B. A non-cholera Vibrio.
C. Campylobacter fetus.
D. Campylobacter jejuni.
E. *Helicobacter pylori.
272.
A person got cholera. The best treatment for cholera is
A. tetracycline
B. toxoid
C. vaccine
D. antiserum injection
E. *rehydration therapy
273.
A person got cholera. The large volume of fluid lost by diarrhea during infection with Vibrio
cholerae
A. is a consequence of fluid replacement during treatment of the disease and does not result directly
from activity of the cholera toxin
B. results from electrolytes binding to the intestinal enterocytes which upsets their water retention
capability
C. results from neurotoxic effects of the cholera toxin on the central nervous system
D. is caused when the vibrios bind to the intestinal epithelium and physically or mechanically block
the uptake of fluids by the gut epithelial cells
E. *follows activation of adenylate cyclase by cholera toxin and the subsequent effect of cyclic
AMP on water and salt balances of the host cells
274.
A young child develops bloody diarrhea, produced by Shigella infection. From which source
was this infection most likely to have been contracted?
A. Rare hamburger.
B. Spores present in soil.
C. Dog or cat.
D. Cow, horse, or sheep.
E. *Another child.
275.
A young man got a dysentery. Which Escherichia coli type is most like Shigella in its virulence
plasmid and mode of infection:
A. EHEC
B. EPEC
C. EAggEC
D. ETEC
E. *EIEC
276.
A young man got a dysentery. Which of the following is not true about Shigella?
A. Causes bacillary dysentery
B. Most strains are lactose nonfermenters
C. Virulence is plasmid mediated
D. The organism multiplies directly in the host cell
E. *Serotyping is based on O and H antigens
277.
A young woman got a dysentery. Humans acquire shigellosis from:
A. dogs
B. cats
C. swine
D. chickens
E. *humans
278.
A young woman got cholera. The hallmark of therapy for severe cases of cholera is:
A. antimicrobial therapy
B. outpatient treatment
C. serotherapy
D. vaccination
E. *replacement of electrolytes
279.
A young woman got cholera. To determine to which species the infectious agent belongs, the
microbiologist performs some tests on colonies cultured from stool samples. These tests include the
following EXCEPT:
A. growth on thiosulfate-citrate-bile-sucrose (TCBS) agar
B. serotyping based on O antigens
C. fermentation of sucrose
D. growth at different NaCl concentrations
E. *serotyping based on H antigens
280.
Among the Sunday night patients at the Smithville emergency room were ten young adults
suffering from severe diarrhea. All of these individuals would normally characterize themselves as
being in good health. All reported eating at a local Dairy fair during the weekend. Of the following
bacterial species the least likely to be responsible is
A. Campylobacter fetus
B. Shigella flexneri
C. Campylobacter jejuni
D. Yersina enterocolitica
E. *Salmonella typhimurium
281.
An engineer recently returned from visiting his family in India develops severe diarrhea. He in
fact has cholera. His diarrhea is produced by a protein exotoxin secreted by Vibrio cholerae. How does
this toxin act?
A. Stimulates guanyl cyclase.
B. Inhibits guanyl cyclase.
C. ADP-ribosylates a chloride transporter.
D. Inhibits a G protein that inhibits adenyl cyclase.
E. *Stimulates a G protein that activates adenyl cyclase.
282.
From a 29-year-old stressed-out medical student with gastritis a urease-positive, spiral-shaped
gram-negative rod is found in gastric washings. Which of the following is most likely to be this
organism?
A. Proteus mirabilis
B. Providencia rettgeri
C. Vibrio cholerae
D. Campylobacter jejuni
E. *Helicobacter pylori
283.
Gastroenteritis caused by Campylobacter jejuni is associated with consumption of contaminated
water or foods which include the following EXCEPT:
A. milk
B. poultry
C. chicken
D. clams
E. *hamburger
284.
Gastroscopy reveals that a patient with stomach pain has a large ulceration of his gastric mucosa.
During the procedure a biopsy of the stomach epithelium is obtained. Which observation would suggest
Helicobacter pylori as the cause of illness?
A. Biopsy shows infiltration of gastric epithelium by lymphocytes.
B. pH of stomach fluid is equal to 1 (normal), rather than decreased.
C. Ingested isotope-labeled nitrate is converted to nitrite in the stomach.
D. Bacteria are found in stomach fluid, but not in contact with the gastric epithelium
E. *Curved or spiral bacteria are seen in the biopsy after silver staining.
285.
Healthy adult travelers visiting Peru are cautioned against eating uncooked vegetables and
unpeeled fruits, and against drinking unbottled water. However, they are already resistant to cholera
because of:
A. the gamma globulin shots they received before their trip.
B. their ability to avoid contaminated food due to its acidic smell.
C. their consumption of large prophylactic amounts of bicarbonates.
D. they were vaccinated
E. *a gastric barrier, due to stomach acids.
286.
If this patient had Shigellosis, the stool culture on MacConkey agar will grow:
A. glucose fermenting colonies
B. pink colonies
C. black colonies
D. lactose fermenting colonies
E. *non-lactose fermenting colonies
287.
In a 30-year old patient with fever, nausea, vomiting and bloody diarrhea, all of the following
bacteria should be considered in the diffrential diagnosis, except one:
A. Salmonella
B. Yersinia
C. ETEC
D. Shigella
E. *Campylobacter
288.
Outbreaks of diarrhea caused by species of Shigella are common in day-care centers for children
and other similar settings. What property of Shigella most enhances its spread between children?
A. Frequent presence in the upper respiratory tracts of children who are not ill
B. Ability to ferment lactose and grow in refrigerated milk.
C. Possession of an envelope resistant to disinfectants.
D. Carriage by common classroom pets such as hamsters and gerbils
E. *Resistance to stomach acid and low infectious dose.
289.
Salmonella, Yersinia, Escherichia and Shigella are put together in Bergey's Manual because they
are all
A. gram-positive aerobic cocci
B. fermentative
C. none answers are correct
D. pathogens
E. *gram-negative facultatively anaerobic rods
290.
The microbiologist is aware that the gastroenteritis outbreak is associated with the consumption
of raw seafood at a local restaurant. She considers it may be due to a number of vibrios EXCEPT:
A. V. parahaemolyticus
B. V. alginolyticus
C. V. vulnificus
D. V. cholerae non 01
E. *V. fluvialis
291.
23-year-old woman comes to your office because, for 3 days, she has experienced burning with
urination, increased frequency of urination, and a continual feeling that she needs to urinate. She does
not have vaginal discharge, fever, or flank pain. Rapid 'dipstick' urine tests are consistent with
uncomplicated cystitis. Culture of urine on standard media produces a lactose-fermenting Gramnegative rod. In situations such as this, what is the most likely pathogen?
A. Enterobacter faecium
B. Klebsiella pneumoniae
C. Proteus vulgaris
D. Pseudomonas aeruginosa
E. *Escherichia coli
292.
A 20-year-old college student goes to the student health center because of dysuna, frequency,
and urgency on urination for 24 hours. She has recently become sexually active. On urmalysis, many
polymorphonuclear cells are seen. The most likely organism responsible for these symptoms and signs
is
A. Staphylococcus aureus
B. Streptococcus agalactiae
C. Gardnerella vaginalis
D. Lactobacillus species
E. *Escherichia coli
293.
A 23-year-old woman has a history of recurrent urinary tract infections, including at least one
episode of pyelonephritis. Blood typing shows the P blood group antigen. Which of the following is
likely to be the primary cause of her infections7
A. Escherichia coli that produce heat-stable toxin
B. Escherichia coli with K1 (capsular type 1) antigen
C. Escherichia coli O139 (lipopolysaccharide O antigen 139)
D. Escherichia coli O157 H7 (lipopolysaccharide O antigen 157, flagellar antigen
E. *Escherichia coli with P-pili (fimbriae)
294.
A 27 year-old woman is admitted to the hospital because of fever, with increasing anorexia,
headache, weakness, and altered mental status of 2 days'duration. She works for an airline as a cabin
attendant, flying between the Indian subconti nent and other places in Southeast Asia and the West
Coast of the USA. Ten days prior to admission she had a diarrheal illness that lasted for about 36 hours.
She has been constipated forthe last 3 days. Her temperature is 39 °C, heart rate 68/min, blood pressure
120/80 mm Hg, and respirations 18/mm. She knows who she is and where she is but does not know the
date. She is picking at the bed clothes. Rose spots are seen on the trunk. The remainder of the physical
examination is normal. Blood cultures are done and an intravenous line is placed. The most likely cause
of her illness is
A. Enterotoxigenic Escherichia coli (ETEC)
B. Shigella sonnei
C. Salmonella enterica subspecies enterica serotype Typhimunum (Salmonella Typhimurium)
D. Enteroinvasive Escherichia coli (EIEC)
E. *Salmonella enterica subspecies enterica serotypeTyphi (SalmonellfaTyphi)
295.
A 60-year old man was admitted to the hospital 2 weeks previously because of head trauma and
other injuries that resulted from an automobile accident. A urinary tract catheter was inserted at
admission and remains in place. The man develops a urinary tract infection with a gram negative
bacillus. The probable cause of this patients infection is
A. Pseudomonas aeruginosa
B. Providenaa rettgeri
C. Escherichia coli
D. Morganella morgana
E. *Indeterminable without culture and identification testing
296.
A common serotype of enterohemorrhagic E. coli is ::A common serotype of enterohemorrhagic
E. coli is O157:H7. To which bacterial structure does the "H7" correspond?
A. Pili.
B. Capsule.
C. LPS core polysaccharide.
D. Porins.
E. *Flagella.
297.
A five-day-old child develops high fever and stiff neck. A spinal tap is performed. A Gramstained smear of cerebrospinal fluid reveals many neutrophils and short, thick, Gram-negative rods of
uniform length. This microbes can ferment lactose.Which organism below is most likely to have caused
this infection?
A. Haemophilus influenzae
B. Streptococcus pneumoniae
C. Neisseria meningitidis
D. Streptococcus agalactiae
E. *Escherichia coli
298.
A patient becomes infected with Salmonella enterica serotype typhi. Which condition would
most strongly favor development of a “chronic carrier state” with this organism?
A. Age over 70 years.
B. Infection via the respiratory route.
C. Kidney stones.
D. Chronic pulmonary disease.
E. *Gallstones.
299.
A patient with septicemia goes into septic shock. Blood cultures later showed the pathogen to be
Escherichia coli. Which component of the bacteria was most likely to have produced shock?
A. Capsular polysaccharide.
B. Teichoic acid.
C. A superantigen toxin.
D. Plasma membrane lipids.
E. *Lipopolysaccharide [LPS].
300.
A reason not to administer beta lactam antibiotics for a Gram-negative septicemia (blood-borne
infection), unless there is no other alternative, is
A. the antibiotic eliminates the normal flora
B. the lysis of bacterial cells increases the activity of bacterial LPS
C. Complement activation cannot occur in the presence of the antibiotic
D. the antibiotic suppresses the immune response necessary to eliminate the pathogen
E. *beta lactam antibiotics are ineffective against Gram-negative bacteria
301.
A seven-day-old child develops high fever and stiff neck. A spinal tap is performed. A Gramstained smear of cerebrospinal fluid reveals many neutrophils and short, thick, Gram-negative rods of
uniform length. This microbes can ferment lactose.Which organism below is most likely to have caused
this infection?
A. Haemophilus influenzae
B. Streptococcus pneumoniae
C. Neisseria meningitidis
D. Streptococcus agalactiae
E. *Escherichia coli
302.
A sexually-active woman develops a urinary tract infection which ascends to the kidneys. Blood
culture yields a ?-hemolytic Gram-negative rod. In this situation, which pathogen is most common?
A. Klebsiella pneumoniae.
B. Pseudomonas aeruginosa.
C. Salmonella enteritidis.
D. Serratia marcescens
E. *Escherichia coli.
303.
A specimen of thick, bloody sputum from a hospitalized 80-year-old patient with chronic
obstructive pulmonary disease is sent for laboratory analyses. The tests yield heavy growth of a lactosepositive, nonmotile, gram-negative rod with a large gelatinous capsule. Which of the following is this
bacterium most likely to be?
D. coli
A. Enterobacter aerogenes
B. P. aeroginosa
C. Y. pseudotuberoulosis
D. *K. pneumoniae
304.
A stool sample is plated on standard Endo -agar plates. After overnight incubation some of the
colonies are dark pink in color, others are pale, nearly colorless. What can you conclude about the
bacteria that produced dark-pink colonies?
A. Gram-positive.
B. Not likely to be ‘normal flora’.
C. Non-motile.
D. Produce capsules
E. *Ferment lactose.
305.
A strain of bacteria produced colorless colonies when cultured on standard MacConkey agar. It
was then used to inoculate a Sugar-Iron Agar slant. After overnight incubation, the tube was entirely
yellow and there were numerous bubbles inside the agar. There is no black precipitate. Which of the
following descriptions most accurately describes the metabolic reasons for these observations?
A. Produces H2S and gas
B. *Ferments lactose and produces gas
C. Ferments sucrose and produces gas.
D. Ferments neither lactose nor sucrose
E. Ferments glucose only
306.
A vacationer develops watery diarrhea but not chills or fever. In this setting which of the
following pathogens is the most common?
A. Salmonella enterica
B. Staphylococcus aureus
C. Campylobacter jejuni
D. Helicobacter pylori
E. *Escherichia coli
307.
A vacationer has “Traveler’s diarrhea” produced by enterotoxigenic E. coli. His profuse watery
diarrhea is produced by a protein exotoxin secreted by this bacterium. Which statement below best
describes the effect of this exotoxin?
A. Kills enterocytes and produces ulceration and inflammation.
B. Paralyzes phagocytosis by neutrophils.
C. Blocks adsorption of nutrients by enterocytes.
D. Causes rearrangement of the enterocyte cytoskeleton and disappearance of the brush border.
E. *Stimulates ion transport by enterocytes into the intestinal lumen.
308.
A vacationing couple both develop severe watery diarrhea which lasts three days. Which
organism is the most common etiologic agent of such infections?
A. Shigella sonnei.
B. Pseudomonas aeruginosa
C. Salmonella typhi.
D. Campylobacter jejuni.
E. *Escherichia coli.
309.
A young woman develops urgency, frequency, and dysuria. Two days later she develops fever,
chills, and costovertebral angle tenderness. Tests of urine for leukocyte esterase and nitrate reductase are
positive. Urine culture yields a beta-hemolytic Gram-negative rod which forms dark-pink colonies on
MacConkey agar. Which of the following organisms is most likely?
A. Pseudomonas aeruginosa
B. Klebsiellla pneumoniae
C. Staphylococcus saprophyticus
D. Enterobacter, sp
E. *Escherichia coli
310.
A young woman has a urinary tract infection caused by E. coli. By what route are such infections
most commonly acquired?
A. Respiratory route, followed by spread from the anterior nares.
B. Respiratory route, followed by spread from the oro-pharyngeal region.
C. Intestinal infection, followed by spread of bacteria to the urethra via the bloodstream.
D. Direct contact route
E. *Fecal-oral route, followed by colonization of the intestine and then the perineum.
311.
A young woman has a urinary tract infection caused by E. coli. By what route are such infections
most commonly acquired?
A. Respiratory route, followed by spread from the anterior nares.
B. Respiratory route, followed by spread from the oro-pharyngeal region.
C. Intestinal infection, followed by spread of bacteria to the urethra via the bloodstream.
D. Direct contact route
E. *Fecal-oral route, followed by colonization of the intestine and then the perineum.
312.
After inoculation of the patient’s faces on Endo medium there were grown to types of colonies:
one – red with metallic hue, other - colorless. To what group of nutrient media does Endo medium
belong to?
A. Elective
B. Enriching media
C. Universal
D. Selective
E. Differential diagnostic
313.
An old man has a urinary tract infection caused by E. coli. By what route are such infections
most commonly acquired?
A. Respiratory route, followed by spread from the oro-pharyngeal region.
B. Respiratory route, followed by spread from the anterior nares.
C. Intestinal infection, followed by spread of bacteria to the urethra via the bloodstream.
D. coli spreads from skin
E. *Fecal-oral route, followed by colonization of the intestine and then the perineum.
314.
An uncommon serotype of Salmonella enterica subspecies enterica was found by laboratories in
the health departments of adjacent states. The isolates were all from a small geographic area on either
side of the border between the states, suggesting a common source for the isolates (All the isolates were
from otherwise healthy young adults who smoked marijuana the same salmo nella was isolated from a
specimen of the marijuana). By what method did the laboratories determine that these isolates were the
same?
A. Capsular (K antigen) typing
B. DNA sequencing
C. Sugar fermentation pattern determination
D. Decarboxylase reaction pattern determination
E. *O antigen and H antigen typing
315.
Bacteriologists (using the Kauffman-White classifi::Bacteriologists (using the Kauffman-White
classification) made conclusion that outbreak has been caused by Salmonella enterica, serotype
Anatum. Structure of which pair of antigens determined the serotype as Anatum?
A. Heat-labile and heat-stable enterotoxins.
B. Peptidoglycan and teichoic acid.
C. Pili and capsular polysaccharide.
D. Hemolysin and cell-wall-associated carbohydrate.
E. *Flagella and O-antigen.
316.
from blood cultures of the patient a non lactose fermenting gram negative bacillus grows. Which
of the following is likely to be a constituent of this organism?
A.
B.
C.
D.
E.
antigen 157, H antigen 7 (0157 H7)
antigen 139(0139)
Urease
K1 (capsular type l)
*Vi antigen (capsule, virulence antigen)
317.
During a vacation at a Caribbean resort, a 26-year-old executive develops profuse watery
diarrhea. If his illness is produced by E. coli, which virulence factor of this organism is most likely to be
responsible for the diarrhea?
A. A conjugative plasmid that contains antibiotic-resistance transposons.
B. A pathogenicity island which enables E. coli to invade mammalian cells.
C. An iron-transport system more efficient than that present in non-pathogenic E. coli.
D. A toxin that cleaves ribosomal RNA's.
E. *A plasmid-borne gene which encodes a heat-stable peptide toxin that stimulates guanyl cyclase.
318.
Epidemiologists (using the Kauffman-White classification) report that an outbreak has been
caused by Salmonella enterica, serotype Newport. Structure of which pair of antigens determined the
serotype as Newport?
A. Heat-labile and heat-stable enterotoxins.
B. Pili and capsular polysaccharide.
C. Peptidoglycan and teichoic acid.
D. Hemolysin and cell-wall-associated carbohydrate
E. *Flagella and O-antigen.
319.
Microbiologists (using the Kauffman-White classification) report that an outbreak has been
caused by Salmonella enterica, serotype Newport. Structure of which pair of antigens determined the
serotype as Newport?
A. Heat-labile and heat-stable enterotoxins.
B. *Flagella and O-antigen.
C. Pili and capsular polysaccharide.
D. Peptidoglycan and teichoic acid.
E. Hemolysin and cell-wall-associated carbohydrate.
320.
Several medical students go to Cancun over spring break. One evening, at a local bar, they drink
several pitchers of Margaritas made with crushed ice. They spend the next two days in their hotel room
with severe watery diarrhea, but no chills or fever. By the third day they recover completely. Which
organism is most likely to have been the cause of their illness?
A. Non-typhoidal Salmonella
B. Helicobacter pylori.
C. Campylobacter jejuni.
D. Non-cholera Vibrio.
E. *Enterotoxigenic E. coli.
321.
The main effect of E. coli and Vibrio cholerae enterotoxin on host cells of the gastrointestinal
tract that leads to the pathology of the diseases, is to
A. inhibit protein synthesis
B. cleave host cell membranes
C. act as superantigens to trigger an overwhelming immunological reaction
D. initiate a localized inflammatory response in the intestine
E. *cause fluid and electrolyte imbalance
322.
Water to be used for parenteral injection must sterilized to kill living microbes and then further
purified to remove non-living bacterial components. Of those listed below, which is the most toxic?
A. Polysaccharides of capsules.
B. Plasma-membrane lipids.
C. Proteins of the outer membrane.
D. Nucleic acids
E. *Lipopolysaccharide.
323.
What color does acquire the semi-solid Hiss media with the rosolic acid as indicator when
bacteria utilize sugar?
A. *red
B. green
C. brown
D. a color does not change
E. dark blue
324.
Your patient is a 70-year-old man who under went bowel surgery for colon cancer 3 days ago.
He now has a fever and abdominal pain. You are concerned that he may have peritonitis. Which one of
the following pairs of organisms is MOST likely to be the cause?
A. Bordetella pertussis and Salmonella enteritidis
B. Actinomyces israelii and Campylobacter jejuni
C. Clostridium botulinum and Shigella dysente-riae
D. All answers are true
E. *Bacteroides fragilis and Klebsiella pneumoniae
325.
What is the main effect of E. coli and Vibrio cholerae enterotoxin on host cells of the
gastrointestinal tract that leads to the pathology?
A. inhibit protein synthesis
B. cleave host cell membranes
C. act as superantigens to trigger an overwhelming immunological reaction
D. initiate a localized inflammatory response in the intestine
E. *cause fluid and electrolyte imbalance
Test’s questions to figures
1. What does this figure show? Fig. 68
A. *Reassortment of Influenza Viruses
B. Antigenic drifts
C. Partial variation of influenza virus
D. Transformation between bird’s and human’s influenza viruses
E. Transduction between bird’s and human’s influenza viruses
2. What virus is in this figure? Fig. 69
A. Herpes simlex virus 1
B. Varicella-Zoster virus
C. Picornavirus
D. *Adenovirus
E. Cytomegalovirus
3. What virus is in this figure? Fig. 70
A. Herpes simlex virus 1
B. Varicella-Zoster virus
C. Picornavirus
D. Adenovirus
E. *Bunyavirus
4. Which type of the capsomers arrangement around the nucleic acid is shown in figure? Fig. 71
A. Complex symmetry
B. *Helical symmetry
C. Icosahedral symmetry
D. Irregular symmetry
E. Polyhedron symmetry
5. Which stage of the viral replication among listed is not unique for this virus? Fig. 72
A. Adsorption
B. DNA entry into cell
C. *Uncoating
D. Assembly
E. Release
6. Which from the following viruses has such a morphology and ultrastructure? Fig. 82
A. Bunyavirus
B. Orthomyxovirus
C. Adenovirus
D. *Picornavirus
E. Parvovirus
7. Which test mechanism is shown in this figure? Fig. 83
A. Hemadsorption
B. *Hemagglutination
C. Agglutination
D. Hemolysis
E. Coagglutination
8. What viral disease main reservoir do these animals comprise? Fig. 84
A. Japanese encephalitis
B. Yellow fever
C. Herpetic keratoconjuctivitis
D. *Hemorrhagic fever with kidney syndrom
E. Fever, arthralgia
9. What human virus can have such morphology? Fig. 85
A. Mumps virus
B. Herpes virus
C. Poliovirus
D. Rotavirus
E. *Influenza virus
10. Which viral disease is observed in a child? Fig. 86
A. Mumps disease
B. Measles
C. *RSV-bronchopneumonia
D. Rotaviruses enteritis
E. Herpes simplex 1
11. What viral diseases this symptom is pathognomic for? Fig. 87
A. Mumps
B. *Measles
C. Influenza
D. Varicella
E. Herpes simplex 1
12. What immunological test is shown in the figure? Fig. 88
A. Hemadsorption
B. *Hemagglutination inhibition test
C. Agglutination
D. Complement fixation test
E. Coagglutination
13. Which virus can cause this disease? Fig. 89
A. Mumps virus
B. Herpes virus
C. *Poliovirus
D. Rotavirus
E. Influenza virus
14. Which virus can cause this skin and mucosa lesion (vesicle)? Fig. 90
A. Mumps virus
B. Adenovirus
C. *Herpes simplex 1
D. Rotavirus
E. Influenza virus
15. What phenomenon is shown in this figure? Fig. 91
A. Interaction between cells in the immune response
B. Cytotoxic action of mammalian viruses on the host cells
C. Lysogenic life cycle of the bacterial viruses
D. *Lytic life cycle of the bacterial viruses
E. Retroviruses replication
16. What objects are represented in the figure? Fig. 92
A. Artificial nutrience media
B. Method of obtaining inactivated vaccine
C. *Different tissue cell cultures
D. Glass for virus cultivation
E. Glass dishes for serological tests
17. What does this man do? Fig. 93
A. He dillutes patient’s serum
B. He inoculates infected material into meat pepton broad
C. *He works with tissue culture
D. He examinates pH of nutrience medium
E. He prepares viral specimens for electron microscopy
18. What family does this virus belong to? Fig. 94
A. Rhabdoviridae
B. Picornaviridae
C. *Paramyxoviridae
D. Orthomyxoviridae
E. Bunyaviridae
19. What virus is in figure? Fig. 43
A. HAV
B. HBV
C. *HCV
D. HDV
E. HEV
20. What virus is in the figure? Fig. 44
A. HAV
B. HBV
C. HCV
D. *HDV
E. HEV
21. What virus is in the figure? Fig. 45
A. HAV
B. *HIV
C. Herpesvirus
D. Adenovirus
E. HEV
22. What virus is in the figure? Fig. 46
A. *HAV
B. HBV
C. HCV
D. HDV
E. HEV
23. What virus is in the figure? Fig. 66
A. HEV
B. HDV
C. HCV
D. *HBV
E. HAV
24. Replication cycle of what viruses is here in this figure? Fig. 47
A. HAV
B. Herpesvirus
C. Adenovirus
D. *HIV
E. Poxvirus
25. What structural element of HIV is marked in by letter A? Fig. 48
A. *RNA
B. DNA
C. Reverse transcrtiptase
D. p17 Matrix protein
E. No correct answer
26. What structural element of HIV is marked in by letter B? Fig. 48
A. Reverse transcrtiptase
B. p24 capsid protein
C. Envelope (lipid membrane)
D. gp120 envelope protein
E. *gp41 envelope protein
27. What structural element of HIV is marked in by letter C? Fig. 48
A. Reverse transcrtiptase
B. p24 capsid protein
C. Envelope (lipid membrane)
D. *gp120 envelope protein
E. gp41 envelope protein
28. What structural element of HIV is marked in by letter D? Fig. 48
A. Reverse transcrtiptase
B. *p17 Matrix protein
C. Envelope (lipid membrane)
D. gp120 envelope protein
E. gp41 envelope protein
29. What structural element of HIV is marked in by letter E? Fig. 48
A. Reverse transcrtiptase
B. p17 Matrix protein
C. *Envelope (lipid membrane)
D. gp120 envelope protein
E. gp41 envelope protein
30. What structural element of HIV is marked in by letter F? Fig. 48
A. Reverse transcrtiptase
B. p17 Matrix protein
C. Envelope (lipid membrane)
D. *p24 capsid protein
E. gp41 envelope protein
31. What structural element of HIV is marked in by letter G? Fig. 48
A. *Reverse transcrtiptase
B. p17 Matrix protein
C. Envelope (lipid membrane)
D. p24 capsid protein
E. gp41 envelope protein
32. There are clinical signs of what disease? Fig. 49
A. Herpes infection
B. Adenoviral infection
C. *Kaposi’s sarcoma
D. Small pox
E. No correct answer
33. What viruses are there in the figure? Fig. 50
A. HBV
B. HCV
C. HDV
D. *HIV
E. Polioviruses
34. What is there in the figure? Fig. 51
A. Blood transfusion
B. *Routes of AIDS transmission
C. Rhesus conflict
D. Drug injection
E. No correct answer
35. What is there in the figure? Fig. 52
A. Primary immune response in AIDS’ patient
B. Secondary immune response in AIDS’ patient
C. *Evolution of antibodies in AIDS’ patient
D. Evolution of viral antigens in AIDS’ patient
E. No correct answer
36. What causative agents are there in the figure? Fig. 53
A. Herpes virus
B. Adenovirus
C. *Pneumocystis carinii
D. HIV
E. HBV
37. What causative agents are there in the figure? Fig. 54
A. Pneumocystis carinii
B. *Histoplasma capsulatum
C. Cryptosporidium
D. Cryptococcus neoformans
E. Aspergillus niger
38. What causative agents are there in the figure? Fig. 55
A. Pneumocystis carinii
B. Histoplasma capsulatum
C. *Cryptosporidium
D. Cryptococcus neoformans
E. Aspergillus niger
39. There are clinical signs of what disease? Fig. 56
A. Herpes infection
B. Adenoviral infection
C. Kaposi’s sarcoma
D. Small pox
E. *Candidiasis
40. There are clinical signs of: Fig. 57
A. Herpetic infection
B. Adenoviral infection
C. Haemorrhagic fever
D. Small pox
E. *Kaposi’s sarcoma
41. There are clinical signs of: Fig. 58
A. Herpetic infection
B. Adenoviral infection
C. Haemorrhagic fever
D. *AIDS
E. Kaposi’s sarcoma
42. This test is used for diagnosis if AIDS. There is: Fig. 59
A. Hemagglutination test
B. Hemagglutination inhibition test
C. Neutralization test
D. *ELISA
E. Western-blot test
43. This test is used for diagnosis if AIDS. There is: Fig. 60
A. Hemagglutination test
B. Hemagglutination inhibition test
C. Neutralization test
D. ELISA
E. *Western-blot test
44. Replication cycle of what viruses is there in this figure? Fig. 61
A. *HAV
B. HBV
C. HDV
D. HIV
E. HCV
45. What is there in the figure? Fig. 62
A. *Typical Serologic Course of Acute Hepatitis A
B. Typical Serologic Course of Chronic Hepatitis A
C. Concentration of HAV in human body
D. All answers are correct
E. No correct answer
46. There is genome structure of: Fig. 63
A. HAV
B. *HBV
C. HCV
D. HDV
E. HEV
47. Select the chart of Adenovirus among the represented: Fig. 37
A. *1
B. 2
C. 3
D. 4
E. 5
48. Select the chart of Herpes simplex virus among the represented: Fig. 35
A. *1
B. 2
C. 3
D. 4
E. 5
49. Select the chart of Rabdovirus among the represented: Fig. 36
A. 1
B. 2
C. 3
D. 4
E. *5
50. Select the chart of Rotavirus among the represented: Fig. 37
A. 3
B. *4
C. 5
D. 6
E. 7
51. Select the chart of Coronavirus among the represented: Fig. 35
A. 1
B. 2
C. 3
D. *4
E. 5
52. Select the chart of Arenavirus among the represented: Fig. 35
A. *7
B. 6
C. 5
D. 4
E. 3
53. Select the chart of Bunyavirus among the represented: Fig. 35
A. *2
B. 3
C. 4
D. 5
E. 6
54. Select the chart of Togavirus among the represented: Fig. 36
A. 1
B. *2
C. 3
D. 4
E. 5
55. Select the chart of Flavivirus among the represented: Fig. 36
A. 1
B. 2
C. 3
D. 4
E. *5
56. What virus is shown on the figure: Fig. 34
A. Herpes simplex virus
B. Adenovirus
C. Picornavirus
D. *Bunyavirus
E. Rabdovirus
57. What virus is shown on the figure: Fig. 23
A. Herpes simplex virus
B. Adenovirus
C. Picornavirus
D. Bunyavirus
E. *Rabdovirus
58. What virus is shown on the figure: Fig. 24
A. *Rabdovirus
B. Herpes simplex virus
C. Adenovirus
D. Picornavirus
E. Bunyavirus
59. What virus is shown on the figure: Fig. 25
A. Herpes simplex virus
B. *Adenovirus
C. Picornavirus
D. Bunyavirus
E. Rabdovirus
60. What virus is shown on the figure: Fig. 26
A. *Herpes simplex virus
B. Adenovirus
C. Picornavirus
D. Bunyavirus
E. Rabdovirus
61. Which virus is carried by this insect? Fig. 27
A. *Japanese encephalitis
B. Omsk hemorrhagic fever
C. Tick-borne encephalitis
D. Influenza virus
E. Crimea-Congo hemorrhagic fever
62. Which virus is carried by the tick? Fig. 28
A. Japanese encephalitis
B. Dengue fever
C. Yellow fever
D. Influenza virus
E. *Crimea-Congo hemorrhagic fever
63. Which virus can cause such a disease? Fig. 29
A. Japanese encephalitis
B. *Rubella virus
C. Yellow fever
D. Influenza virus
E. Crimea-Congo hemorrhagic fever
64. Which virus can cause such a disease? Fig. 30
A. Influenza virus
B. Rubella virus
C. *Herpes simplex virus
D. Adenovirus
E. Picornavirus
65. Which virus can cause such a disease? Fig. 31
A. Cytomegalovirus
B. Herpes simplex virus
C. *Herpes zoster
D. Adenovirus
E. Coxsackievirus
66. Which virus can cause such a symptom of a disease? Fig. 32
A. *Herpes zoster
B. Cytomegalovirus
C. Herpes simplex virus
D. Adenovirus
E. Coxsackievirus
67. Which virus can cause the disease of this child? Fig. 33
A. Cytomegalovirus
B. Herpes simplex virus
C. Adenovirus
D. *Varicella zoster virus
E. Coxsackievirus
68. The 11 year old child has been hospitalized with the fever and rash which initially has occurred on the
face and neck, and has spread to the trunk, arms extension surfaces, buttocks, hips the same day. What
disease symptoms are these? Fig. 41
A. Measles
B. German measles
C. *Rubella
D. Chickenpox
E. Typhus
69. Which virus embryotoxic action causes congenital malformations such as cataract? Fig. 42
A. Adenovirus
B. Herpes zoster
C. *Rubella virus
D. Coronavirus
E. Rotavirus
70. The symptoms of shingles are depicted on the figure. What type of infection process does this disease
belong? Fig. 31
A. *Persistant infection
B. Reinfection
C. Superinfection
D. Latent infection
E. Mixed infection
71. Which disease symptoms are performed on the figure? Fig. 39
A. Candidiasis
B. *Herpes infection
C. Avitaminosis
D. Periodontosis
E. Dysbacteriosis
72. What virus causes gingivostomatitis? Fig. 30
A. *Herpes simplex virus type 1
B. Herpes simplex virus type 2
C. Varicella zoster virus
D. Epstain-Bar virus
E. Cytomegalovirus
73. The child’s symptoms are: swollen peripheral lymph nodes, fever, malaise, tonsillitis. The previous
diagnosis is infectious mononucleosis. What kind of virus does it cause? Fig. 38
A. Herpes simplex virus type 1
B. Herpes simplex virus type 2
C. Varicella zoster virus
D. *Epstain-Bar virus
E. Cytomegalovirus
74. The child’s inspection reveals the fever of 38C, papular-vesicular rash on the skin and mucous
membranes. Which disease do they belong? Fig. 40
A. Measles
B. Rubella
C. *Chickenpox
D. Shingles
E. German measles
75. A 3 month old child has symptoms of the cataract. Neither traumas nor diseases took place after the
child birth. During the pregnancy the mother contracted an acute virus disease. What virus might cause
fetal malformations? Fig. 42
A. Varicella zoster virus
B. Morbilli virus
C. Rubula virus
D. *Rubella virus
E. Epstain-Bar virus
76. This rash is typical for: Fig. 78
A. Streptococcal impetigo
B. *Herpes simplex
C. Chickenpox
D. Smallpox
E. Infectious mononucleosis
77. Which disease pathogenesis is represented on the chart? Fig. 79
A. Chickenpox
B. Shingles
C. *Herpes simplex
D. Infectious mononucleosis
E. Cytomegalic inclusion disease
78. Patient K. has the following symptoms: fever, intoxication, papular rash on the whole body. What
diagnosis is suspected? Fig. 73
A. Measles
B. Chickenpox
C. Allergic dermatitis
D. *Rubella
E. Streptococcal impetigo
79. Patient’s symptoms are fever, papular rash covering the body and face, intoxication. What previous
diagnosis is the most appropriate? Fig. 74
A. *Rubella
B. Streptococcal impetigo
C. Allergic dermatitis
D. Chickenpox
E. Measles
80. The chart represents the pathogenesis of a certain virus disease. Select one among all: Fig. 80
A. Rubella
B. Herpes simplex
C. *Shingles
D. Cytomegalic inclusion disease
E. Infectious mononucleosis
81. The 3 year old child symptoms are: fever, intoxication, maculopapular rash on the face, trunk and
extremities, redness of the pharynx mucous membranes. What previous diagnosis is the most
appropriate? Fig. 81
A. Measles
B. Chickenpox
C. Infectious mononucleosis
D. *Rubella
E. Streptococcal impetigo
82. What virus can cause such a rush? Fig. 76
A. Variola virus
B. *Varicella zoster virus
C. Herpes simplex virus
D. Cytomegalovirus
83. The rash on the photo is typical for: Fig.76
A. Smallpox
B. Chickenpox
C. Herpes simplex
D. *Shingles
E. Cytomegalic inclusion disease
84. Which disease pathogenesis is represented on the chart? Fig.77
A. Cytomegalic inclusion disease
B. Measles
C. Epidemic parotitis
D. *Herpes simplex
E. Chickenpox
85. Which disease symptoms can be found in a child? Fig.67
A. Measles
B. *Rubella
C. Chickenpox
D. Streptococcal impetigo
E. Hives
86. What agent can cause such a rash? Fig.75
A. Herpes simplex
B. *Varicella zoster virus
C. Cytomegalovirus
D. Streptococcus
E. Variola virus
87. What is the expected diagnosis? Fig.75
A. Measles
B. Rubella
C. Streptococcal impetigo
D. Chickenpox
E. *Shingles
88. Which virus model is represented in the figure? Fig.69
A. Herpes simplex virus
B. *Adenovirus
C. Togavirus
D. Bunyavirus
E. Flavivirus
89. What test is there in the figure? Fig. 5
A. CFT
B. Hemagglutination test
C. Hemagglutination inhibition test
D. ELISA
E. *Indirect Hemagglutination test
90. For what purpose was this test used? Fig. 5
A. Detection of unknown antigen
B. Identification of viruses
C. *Detection the level of antiviral antibodies in patient’s serum
D. Detection the level of immunoglobulines
E. Examination the level of incomplete antibodies
91. What component of indirect Hemagglutination test is marked by number 1in? Fig. 5
A. Antigen
B. *Patient’s serum
C. Complement
D. Immunoglobulin
E. Red blood cell coated with antigen
92. What component of indirect Hemagglutination test is marked by number 2 in? Fig. 5
A. Antigen
B. Patient’s serum
C. Complement
D. Immunoglobulin
E. *Red blood cell coated with antigen
93. What is the result marked by number 3 of this test in? Fig. 5
A. Precipitation
B. Agglutination
C. *Hemagglutination
D. Coagglutination
E. Latex-agglutination
94. What test is there in the figure? Fig. 6
A. CFT
B. *Hemagglutination test
C. Hemagglutination inhibition test
D. ELISA
E. Indirect Hemagglutination test
95. What does this test help to examine? Fig. 6
A. *presence of viruses
B. identification of viruses
C. ability to cause red cells’ lysis
D. presence of antibodies in patience’s serum
E. No correct answer
96. What is the positive result of this test in? Fig. 6
A. Precipitation
B. Agglutination
C. *Hemagglutination
D. Coagglutination
E. Latex-agglutination
97. What test is there in the figure? Fig. 7
A. CFT
B. Hemagglutination test
C. *Hemagglutination inhibition test
D. ELISA
E. Indirect Hemagglutination test
98. What is the positive result of this test in? Fig. 7
A. Precipitation
B. Agglutination
C. Hemagglutination
D. Coagglutination
E. *Agglutination of red blood cells absent
99. For what purpose was this test used? Fig. 8
A. Detection of unknown antigen
B. Identification of viruses
C. *Detection the level of antiviral antibodies in patient’s serum
D. Detection the level of immunoglobulines
E. Examination the level of incomplete antibodies
100.
For what purpose was this test used? Fig. 9
A. Detection of unknown antigen
B. *Identification of viruses
C. Detection the level of antiviral antibodies in patient’s serum
D. Detection the level of immunoglobulines
101.
102.
103.
104.
105.
106.
107.
108.
109.
110.
E. Examination the level of incomplete antibodies
What stage of replication of virus is marked by number 1? Fig. 14
A. Uncoating
B. *Adsorption
C. Entry
D. Assembly
E. Release
What stage of replication of virus is marked by number 2? Fig. 14
A. Uncoating
B. Adsorption
C. *Entry
D. Assembly
E. Release
What stage of replication of virus is marked by number 4? Fig. 14
A. Uncoating
B. Adsorption
C. Entry
D. *Assembly
E. Release
What stage of replication of viruse is marked by number 5? Fig. 14
A. *Uncoating
B. Adsorption
C. Entry
D. Assembly
E. Release
What stage of replication of viruse is marked by number 6? Fig. 14
A. Uncoating
B. Adsorption
C. Entry
D. Assembly
E. *Release
What method of inoculation of viruses into chicken embryo is marked by number 1? Fig. 14
A. Allantoic inoculation
B. *Amniotic inoculation
C. Chorionallantoic membrane inoculation
D. Yolk sac inoculation
E. Albumen inoculation
What method of inoculation of viruses into chicken embryo is marked by number 2? Fig. 14
A. Allantoic inoculation
B. Amniotic inoculation
C. *Chorionallantoic membrane inoculation
D. Yolk sac inoculation
E. Albumen inoculation
What method of inoculation of viruses into chicken embryo is marked by number 3? Fig. 14
A. Allantoic inoculation
B. Amniotic inoculation
C. Chorionallantoic membrane inoculation
D. *Yolk sac inoculation
E. Albumen inoculation
What method of inoculation of viruses into chicken embryo is marked by number 4? Fig. 14
A. *Allantoic inoculation
B. Amniotic inoculation
C. Chorionallantoic membrane inoculation
D. Yolk sac inoculation
E. Albumen inoculation
What structure of virus is marked by number 1? Fig. 17
A. Envelope
B.
C.
D.
E.
111.
A.
B.
C.
D.
E.
112.
A.
B.
C.
D.
E.
113.
A.
B.
C.
D.
E.
114.
A.
B.
C.
D.
E.
115.
A.
B.
C.
D.
E.
116.
A.
B.
C.
D.
E.
117.
A.
B.
C.
D.
E.
118.
A.
B.
C.
D.
E.
119.
A.
B.
C.
D.
Capsid
Nucleic acid
Peplomer
*Capsomer
What structure of virus is marked by number 2? Fig. 17
Envelope
Capsid
*Nucleic acid
Peplomer
Capsomer
What structure of virus is marked by number 3? Fig. 17
Envelope
*Capsid
Nucleic acid
Peplomer
Capsomer
What structure of virus is marked by number 1? Fig. 18
*Envelope
Capsid
Nucleic acid
Peplomer
Capsomer
What structure of virus is marked by number 2? Fig. 18
Envelope
*Capsid
Nucleic acid
Peplomer
Capsomer
What structure of virus is marked by number 3? Fig. 18
Envelope
Capsid
*Nucleic acid
Peplomer
Capsomer
What structure of bacteriophage is marked by number 1? Fig. 16
Tail
Contractile sheath
*Head
Base plate
Tail fibres
What structure of bacteriophage is marked by number 2? Fig. 16
*Tail
Contractile sheath
Head
Base plate
Tail fibres
What structure of bacteriophage is marked by number 3? Fig. 16
Tail
*Contractile sheath
Head
Base plate
Tail fibres
What structure of bacteriophage is marked by number 4? Fig. 16
Tail
Contractile sheath
Head
*Base plate
120.
121.
122.
123.
124.
E. Tail fibres
What structure of bacteriophage is marked by number 5? Fig. 16
A. Tail
B. Contractile sheath
C. Head
D. Base plate
E. *Tail fibres
What is there in the figure? Fig. 10
A. Agglutination
B. *Hemagglutination
C. Coagglutination
D. Latex-agglutination
E. Precipitation
What test is there in the figure? Fig. 11
A. Western blot
B. Indirect fluorescent-antibody test
C. Hemagglutination ingibition test
D. *Hemagglutination test
E. Indirect Hemagglutination test
What test is there in the figure? Fig. 12
A. Hemagglutination test
B. *Hemadsorption test
C. Cytopathic effect
D. Syncytium formation
E. Inclusion bodies
What is there in the figure? Fig. 13
A. Hemagglutination test
B. Hemadsorption test
C. Cytopathic effect
D. Syncytium formation
E. *Inclusion (Negri bodies)