Download ID_299_Special- clinical- ecological _English_sem_5

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Which of the following bacteria is cell wall deficient?
Mycoplasma.
Treponema.
Slaphylococcus.
Klebsiella.
Salmonella
Each of the following organisms is an important cause of urinary tract infections EXCEPT:
Escherichia coli
Proteus mirabilis
Klebsiella pneumoniae
Bacteroides fragilis
Staphylococcus epidermidis
Complications of typhoid fever are:
liver abscesses
intestinal perforation
meningitis
neurological damage
sepsis
Shigella is transmitted by
alimentary route
flies
infected dust
air dropled
louse
Antitoxic therapy is useful in:
gas gangrene.
diphtheria.
tetanus
all of the above.
botulism
Haemophilus influenzae needs for growth.
blood
NAD
hemin
X factor
all of the above
Formation of a gummas is
a damaged aorta
a damaged liver
a degenerative lesions
the primary lesion of syphilis
the result of congenital syphilis
The treatment of choice for syphilis is:
antiserum
aurum drug
penicillin
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vaccine
tetracycline
Which of the treponematoses are not veneral disease, except?
bejel
pinta
yaws
endemic syphilis
syphilis
Lyme disease is caused by ______ and spread by ______.
Borrelia recurrentis, lice
Borrelia burgdorferi, ticks
Borrelia burgdorferi, chiggers
Borrelia hermsii, ticks
Borrelia recurrentis, ticks
Epidemic Relapsing fever is spread by
lice
ticks
flea
mosquites
animal urine
Endemic Relapsing fever is spread by
lice
ticks
flea
mosquites
animal urine
The source of Vibrio cholerae infection is
birds
carriers, sick persons
animals
water
food
The best treatment for cholera is
antiserum injection
rehydration therapy
tetracycline
toxoid
vaccine
Rickettsias and chlamydias are similar in being
carried by arthropod vectors
free of a cell wall
obligate intracellular bacteria
produce exotoxin
the cause of eye infections
Which of the following is/are an arthropod vector of rickettsioses?
flea
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louse
tick
all of the above
mosquito
Which organs Chlamydia trachomatis can attack?
eye
urethra
fallopian tubes
lungs
all of these
Each of the following statements concerning neisseriae is correct EXCEPT:
They are gram-negative diplococci
They produce IgA protease as a virulence factor
They are oxidase-positive
They grow best under anaerobic conditions
They have pili
Ornithosis is a _____ infection associated with ______
rickettsial, parrots
chlamydial, mice
chlamydial, birds
rickettsial, flies
chlamydial, rats
BCG vaccine is a:
live attenuated vaccine
killed vaccine
toxoid vaccine.
subcelullar vaccine.
recombinant vaccine.
Mycoplasmas demage next structure of host cells.
nucleus
cell walls
ribosomes
cell membranes
mitochondria
A child develops pneumonia. The bacterium capsulated Streptococcus pneumoniae is cultured
from the patient’s sputum. How did the presence of capsules promote development of serious
disease?
Prevented binding of antibodies to the bacteria.
Prevented initiation of a humoral immune response
Prevented activation of helper T cells
Prevented phagocytosis by neutrophils.
Prevented mast-cell degranulation.
Haemolytic uraemic syndrome is caused by:
enteropathogenic Escherichia coli
enterotoxigenic E. coli.
enteroinvasive E. coli
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enterohaemorrhagic E. coli
enteroaggregative E. coli.
A child under treatment for leukemia is treated with Tetanus immune globulin (human).
Which phrase best describes the immunity that is produced?
Innate and specific.
Innate and humoral.
Innate and cell-mediated.
Acquired and humoral.
Acquired and cell-mediated.
Which of the following media is an enrichment medium for the isolation of Shigella?
Selenite broth.
Tetrathionate broth.
Alkaline peptone water
Taurocholate peptone transport and enrichment medium
Endo medium
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?
Tetanus immune globulin (human)
Tetanus toxoid
Tetanus toxoid Tetanus immune globulin (human) mixed and administered as a single injection.
No immunization
Tetanus toxoid plus Tetanus immune globulin (human),
injected at separate sites.
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, α-hemolytic on sheep blood agar, and catalase-negative. Which organism
below is most likely?
Staphylococcus epidermidis.
Staphylococcus aureus.
Streptococcus pneumoniae.
Streptococcus pyogenes.
Streptococcus agalactiae.
Staphylococcus aureus is easily transmitted within the hospital environment. Which feature of
this bacterium is most largely responsible for its ease of spread?
none of the above
Ability to colonize the upper respiratory tract.
Ability to colonize the digestive tract.
Presence of an outer membrane impermeable to most disinfectants.Production of extracellular
polysaccharide which allows it to adhere tightly to surfaces.
Ability to form spores which are resistant to disinfectants and easily dispersed.
Bacteroides fragilis is isolated from an abdominal abscess. Which phrase is the most appropriate?
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.
Which one of the following statements concern ing Legionella pneumophila is CORRECT?
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It is part of the normal flora of the colon
It cannot be grown on laboratory media
It does not have a cell wall
It is an important cause of pneumonia in renal transplant patients
Legionellosis is sexual transmitted disease
Morphology of Treponema pallidum is:
Spiral-shaped
Mold
Vibrio
Rod
Yeast
Toxin of Vibrio cholerae is:
LPS
Toxic shock syndrome toxin
Enterotoxins
Hemolysins
Toxin - activates adenylate cyclase
Which statement below most accurately describes the role of M protein in virulence of Group A
Streptococci [Streptococcus pyogenes]?
Shows no antigenic variation, so is not a target for antibodies.
Is a ‘superantigen toxin’ which stimulates TH cells.
Stimulates synthesis of antibodies that cross-reacts with heart tissue
Binds Fc regions of Immunoglobulin G molecules.
Inhibit phagocytosis
Which test below would best distinguish S. aureus from one of the less-virulent staphylococci?
Production of catalase
Colony color when grown on BHI agar
Ability to grow on MacConkey agar.
Production of coagulase.
Type of hemolysis on sheep blood agar.
Which of the following staining techniques cannot be used for T. pallidum?
Gram staining.
Giemsa staining.
Silver impregnation staining.
Imunofluorescence staining.
Burri staining.
Louse-borne relapsing fever is caused by:
Borrelia recurrentis.
B. duttoni.
B. burgdorferi.
B. parkeri.
B. persica
Bacterial genus/genera of medical importance
which do not produce endospores is/are: .
Bacillus.
Clostridium.
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both of the above.
Bacteroides
none of the above
Which of the following bacteria dies quickly after drying?
Mycobacterium tuberculosis.
Staphylococcus aureus.
Pseudomonas aeruginosa.
Bacillus anthracis
Treponema pallidium
Which of the following exotoxins is most toxic?
Botulinum toxin.
Tetanus toxin.
Diphtheria toxin.
Cholera toxin.
Shigella toxin
A person is considered non-immune against tetanus if:
he has never had an injection of tetanus toxoid or if he had only one such injection.
more than 6 months have passed after a course of 2 injections.
five to 10 years have passed after the planned course of three injections.
more than 2 months have passed after one an injection of antitetanus serum
all are correct.
Rickettsia typhi is:
Helminths
Protozoa
Fungi
Viruses
Bacteria
An old man has a urinary tract infection caused by E. coli. By what route are such infections most
commonly acquired?
Fecal-oral route, followed by colonization of the intestine and then the perineum.
Respiratory route, followed by spread from the oro-pharyngeal region
Respiratory route, followed by spread from the anterior nares
Intestinal infection, followed by spread of bacteria to the urethra via the bloodstream.
E. coli spreads from skin
The most severe streptococcal diseases are caused by
group A streptococci
group B streptococci
pneumococci
group C streptococci
enterococci
A complication of genital gonorrhea in newborns is
infertility
pelvic inflammatory disease
arthritis
blindness
urethritis
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. Which infectious agent of those covered in the chapter would most likely be acquired from a
contaminated doorknob?
Staphylococcus epidermidis
Streptococcus pyogenes
Neisseria meningitidis
Streptococcus pneumoniae
Staphylococcus aureus
What is the usual habitat of endospore-forming bacteria that are agents of disease?
the intestine of animals
soil
water
foods
dust
Most Bacillus species are
true pathogens
opportunistic pathogens
nonpathogens
commensals
saprophyticus
Many clostridial diseases require a/an ______ conditions for their development.
anaerobic
aerobic
living tissue
low-pH
alkaline pH
Clostridium perfringens causes
myonecrosis, food poisoning
enterocolitis, haemorrhagic syndrom
antibiotic-induced colitis
All of the above
both a and b
The action of tetanus exotoxin is on the
neuromuscular junction
sensory neurons
nucleus of hypocamp
cerebral cortex
spinal interneurons
An infection peculiar to swine causes _______ when transmitted to humans.
anthrax
diphtheria
erysipeloid
plage
tuberculosis
Tuberculosis is spread by
contaminated fomites
food
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respiratory droplets
vectors
urine
Microbial diagnosis of tuberculosis is provided by
X ray
Mantoux test
acid-fast stain
tuberculin test
allergic test
The form of leprosy associated with severe disfigurement of the face is
borderline
chronic
lepromatous
papular
tuberculoid
Group of Candida albicans is:
Bacteria
Protozoa
Viruses
Fungi
Helminths
Which of the following bacteria belong/s to
the family Enterobacteriaceae?
Shigella.
Salmonella.
Yersinia.
Proteus
All answers are corect
The bubo of bubonic plague is a/an
enlarged lymph node
granuloma in the skin
infected sebaceous gland
tumor of lymph node
ulcer where the flea bite occurred
Treponema pallidum is cultured in/on
blood agar
eggs
horse serum
rabit testis
serum broth
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,
Lipopolysaccharide.
Polysaccharides of capsules
Plasma-membrane lipids.
Proteins of the outer membrane.
Nucleic acids
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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?
Poses a reduced risk of serum sickness.
Provides longer-lasting immunity
Provides protection more rapidly.
Results in higher antibody titer.
Also provides secretory IgA for mucosal immunity.
A 20-year-old student has a deep laceration. He received the standard four-doses of
Diphtheria-Pertussis-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?
Tetanus anti-toxin (equine).
Tetanus toxoid.
Tetanus immune globulin (human).
Both Tetanus toxoid and Tetanus immune globulin (human).
Both Tetanus toxoid Tetanus anti-toxin (equine).
Tetanus is very dangerous disease because Clostridium botulini produces exotoxin.
How does this toxin act?
Stimulates adenyl cyclase.
Neurotoxin which cause flaccid paralyzes.
Inhibits guanyl cyclase
Cleaves ribosomal RNA.
Stimulates production of cytokines.
Infective-toxic type of food poisoning is caused by:
Clostridium perfringens.
Salmonella Enteritidis.
Staphylococcus aureus.
Yeasts
Salmonella Dublin.
The symptoms in scarlet fever are due to
streptolysin
coagulase
erythrogenic toxin
alpha toxin
leucocidin
Which of the following agents is the commonest cause of infective endocarditis?
. Staphylococcus epidermidis.
Candida spp.
Viridans group of streptococci.
Coliforms.
Rickettsia
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?
Bacteroides fragilis
Clostridium difficile
Proteus mirabilis
D.
E.
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Bordetella pertussis
Vibrio cholerae
Human body louse is responsible for transmission of which of the following diseases?
Epidemic typhus.
Murine typhus
Rickettsialpox.
Q fever.
Typhi fever
Which of the following specimens is/are most appropriate for culture of bacteria in first week
of enteric fever?
Urine.
Blood.
Faeces.
CSF.
Bile
What is the colour of colonies of C. diphtheriae on blood tellurite agar medium?
White.
Grey to black.
Cream.
Yellow.
Green
Which of the following properties is/are
shown by diphtheria toxin?
It is a heat-labile protein.
It inhibits protein synthesis.
It is produced by Corynebacterium diptheriae strains lysogenic for p phage.
It is exotoxin
All are correct.
Penicillin-resistant Staphylococcus can be treated with ______ without sensitivity testing.
ampicillin
erythromycin
methicillin
amoxycillin
no antibiotic
Ascoli's thermoprecipitin test helps in confirming the laboratory diagnosis of:
anthrax.
tetanus.
typhoid.
cholera.
pertussis
Which organs are affected in a patient with rheumatic fever?
skin, heart
joints, bone marrow
heart valves, kidneys
brain, kidneys
heart, bone marrow
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______ hemolysis is the partial lysis of red blood cells due to bacterial hemolysins.
Alpha
Beta
Gamma
Delta
Epsilon
An effective vaccine exists to prevent crupouse pneumonia from
Staph, aureus
Strep. pyogenes
K. pneumoniae
Strep. pneumoniae
N. meningitidis
Viridans streptococci commonly cause
pneumonia
meningitis
subacute endocarditis
otitis media
arthritis
Which genus of bacteria has pathogens that can cause blindness in newborn?
Branhamella
Staphylococcus
Streptococcus
Neisseria
Shigella
The skin blotches in meningitis are due to
blood clots
endotoxins in the blood
erysipelas
exotoxin in skin
skin invasion by N. meningitidis
Bubonic plague is transmitted by:
. rat flea.
inhalation.
ingestion.
. ticks
all of the above routes.
The pathogenesis of which one of the following diseases does NOT involve an exotoxin?
Scarlet fever
Typhoid fever
Toxic shock syndrome
Botulism
Tetanus
Regarding the effect of benzylpenicillin (penicillin G) on bacteria, which one of the following
organisms is LEAST likely to be resistant?
Staphylococcus aureus
Enterococcus faecalis
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88.
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Streptococcus pyogenes
Neisseria gonorrhoeae
Neisseria meningitidis
Each of the following statements concerning chlamydia is correct EXCEPT:
Obligate intracellular parasite
Gramnegative
Symptomatic infections can be associated with urethral or cervical discharge containing many
polymorphonuclear leukocytes
There is no vaccine against these infections
Chlamydiae are cultivated onto nutritient media
Which one of the following illnesses is NOT a zoonosis?
Typhoid fever
Q fever
Tularemia
Rocky Mountain spotted fever
Brucelosis
Which one of the following is NOT a characteristic of either Neisseria gonorrhoeae or Neisseria
meningitidis?
A protein
Polysaccharide capsule
IgA protease
Pili
Ferments glucose
Which one of the following is NOT an important characteristic of Streptococcus pyogenes?
Protein A
M protein
Beta-hemolysin
Polysaccharide group-specific substance
Produce exotoxins
Each of the following statements concerning wound infections caused by Clostridium
perfringens is correct EXCEPT:
An exotoxin plays a role in pathogenesis
Gram-positive rods are found in the exudate
The organism grows only in human cell culture
Anaerobic culture of the wound site should be ordered
The organism has capsule
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?
Protein A
Capsule
Endotoxin
β-Lactamase
Exotoxin
Each of the following statements concerning Chlamydia trachomatis is correct EXCEPT:
It is an important cause of nongonococcal urethritis
B.
C. *
D.
E.
89.
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90.
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91.
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92.
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93.
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94.
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95.
It
is
the
cause
of lymphogranuloma venereum
It is an important cause of subacute bacterial endocarditis
It is an important cause of conjunctivitis
There is no vaccine against these infections
Which one of the following types of organisms is NOT an obligate intracellular parasite and
there fore can replicate on bacteriologic media?
Chlamydia
Mycoplasma
Adenovirus
Rickettsia
Herpesrirus
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?
Lecithinase of Clostridium perfringens
Hyaluronidase of Streptococcus pyogenes
M protein of Streptococcus pneumoniae
Leukocidin of Staphylococcus aureus
Enterotoxins of Staphylococcus aureus
The soil is the natural habitat for certain microorganisms of medical importance. Which one of
the following is LEAST likely to reside there?
Clostridium tetani
Mycobacterium intracellular
Bacillus anthracis
Chlamydia trachomatis
Clostridium perfringens
Each of the following statements concerning infection with Chlamydia psittaci is correct
EXCEPT:
C psittaci can be isolated by growth in cell culture and will not grow in blood agar
The organism appears purple in Gram-stained smears of sputum
The infection is more readily diagnosed by serologic tests than by isolation of the organism
C psittaci forms inclusion in the cells
The infection is more commonly acquired from a nonhuman source than from another human
Of the organisms listed below, which one is the MOST frequent bacterial cause of pharyngitis?
Escherichia coli
Staphylococcus aureus
Streptococcus pneumoniae
Streptococcus pyogenes
Neisseria meningitidis
Each of the following statements concerning exotoxins is correct EXCEPT:
Some strains of Escherichia coli produce an enterotoxin that causes diarrhea
Cholera toxin acts by stimulating adenylate cyclase
Diphtheria is caused by an exotoxin that inhibits protein synthesis by inactivating an elongation
factor
Botulism is caused by a toxin that hydrolyzes lecithin (lecithinase), thereby destroying nerve cells
Botulism, which is caused by ingesting preformed toxin, can be prevented by boiling food prior to
eating
Each of the following statements concerning the VDRL test for syphilis is correct EXCEPT:
A. *
B.
C.
D.
E.
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97.
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100.
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101.
A.
The antigen is composed of inactivated Treponema pallidum
The test is usually positive in secondary syphilis
False-positive results are more frequent than with the FTA-ABS test
The antibody titer declines with adequate therapy
Reagin is detected in patiant‘s serum
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?
Gram-positive
Ferment lactose.
Not likely to be ‘normal flora’.
Non-motile.
Produce capsules.
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?
Mycoplasma pneumoniae.
Chlamydia pneumoniae
Haemophilus influenzae.
Escherichia coli.
Streptococcus pneumoniae.
In Widal test, the significant titre for О agglutinins is generally:
1: 50 or more.
1:100 or more.
1:200 or more.
1:400 or more.
1:800 or more.
Each of the following statements concerning Corynebacterium diphtheriae is correct EXCEPT:
C. diphtheriae is a gram-positive rod that does not form spores
Toxin production is dependent on the organism's being lysogenized by a bacteriophage
Diphtheria toxoid should not be given to children under the age of 3 years because the incidence of
complications is too high
Antitoxin should be used to treat patients with diphtheria
Toxoid is used for active prophylaxis
Each of the following statements concerning certain gram-negative rods is correct EXCEPT:
Pseudomonas aeruginosa causes wound infections that are characterized by blue-green pus as a
result of pyocyanin production
Invasive disease caused by Haemophilus influenzae is most often due to strains possessing a type b
polysaccharide capsule
Legionella pneumophila infection is acquired by inhalation of aerosols from environmental water
sources
There are different serological types of pathogenic Escherichia coli
Whooping cough, which is caused by Bordetella pertussis, is on the rise because changing
antigenicity has made the vaccine relatively ineffective
Each of the following statements concerning enterotoxins is correct EXCEPT:
Enterotoxins are protein substances
B. *
C.
D.
E.
102.
A.
B.
C.
D. *
E.
103.
A.
B.
C. *
D.
E.
104.
A.
B.
C.
D. *
E.
105.
A. *
B.
C.
D.
E.
106.
A.
B.
C.
D. *
E.
107.
A.
B.
C. *
D.
E.
108.
A. *
Enterotoxins typically cause bloody diarrhea with leukocytes in the stool
Staphylococcus aureus produces an enterotoxin that causes vomiting and diarrhea
Vibrio cholerae causes cholera by producing an enterotoxin that activates adenylate cyclase
Escherichia coli enterotoxin mediates ADP-ribosylation of a G protein
Each of the following statements concerning plague is correct EXCEPT:
Plague is caused by a gram-negative rod that can be cultured on blood agar
Plague is transmitted to humans by flea bite
The main reservoirs in nature are small rodents
Plague is caused by a gram-positive rod that can be cultured on blood agar
There are different clinical form of plague (bubonic, pneumonic, skin)
Which one of the following statements concerning the organisms that cause brucellosis is CORRECT?
Brucellae are transmitted primarily by tick bite
The principal reservoirs of brucellae are small rodents
Brucellae are found in reticuloendothelial cells and often cause granulomatous lesions
Brucellae are obligate intracellular parasites that are usually identified by growth in human cell
culture
Brucellae are obligate intracellular parasites that are usually identified by growth in human cell
culture
Each of the following statements concerning epidemic typhus is correct EXCEPT:
The disease is characterized by a rash
The Weil-Felix test can aid in diagnosis of the disease
The disease is caused by a rickettsia
The disease is caused by salmonella typhi
Vaccine is used for specific prophylaxis
Ticks are vectors for the transmission of each of the following diseases EXCEPT:
epidemic typhus
Tick-borne encephalytis
Lyme disease
Crimean-Congo haemorrhagic fever
Rocky Mountain spotted fever
Each of the following statements concerning pneumonia caused by Mycoplasma pneumoniae is
correct EXCEPT:
The disease is associated with a rise in the titer of cold agglutinins
The disease occurs primarily in immunocompetent individuals
The disease is one of the "atypical" pneumonias
The organism cannot be cultured in vitro because it has no cell wall
Penicicllin is uneffective agains Mycoplasma
Each of the following statements concerning Neisseria meningitidis is correct EXCEPT:
It is an oxidase-positive, gram-negative diplococcus
It contains endotoxin in its cell wall
It produces an exotoxin that stimulates adenylate cyclase
It has a polysaccharide capsule that is antiphagocytic
It can utilize glucose and maltose
Each of the following statements concerning Q fever is correct EXCEPT:
Rash is a prominent feature
B.
C.
D.
E.
109.
A.
B.
C.
D. *
E.
110.
A.
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. *
It is transmitted by respiratory aerosol
Farm animals are an important reservoir
It is intracellular parazite
It is caused by Coxiella burnetii
Caseous lesions containing inflammatory white blood cells are
syphiloma
pseudomembranes
eschars
tubercles
papular
Which infectious agent cause pseudomembranous collitis?
Mycobacterium tuberculosis
Corynebacterium diphtheriae
Mycobacterium leprae
Clostridium difficile
Shigella sonnei
Treponema pallidum can be cultivated in:
rabbit testes.
blood agar medium.
chocolate agar medium.
Thayer-Martin medium.
Kitt-Tarozi medium
Relapses in relapsing fever occur due to:
antigen variation in bacteria.
increased toxin production by bacteria.
increased invasiveness of bacteria.
super infection with viruses.
increased fermentative activity of bacteria
Sterols are present in the cytoplasmic membrane of:
Mycoplasma.
Bacillus.
Clostridium.
Proteus.
Rickettsia
Which of the following bacteria can grow in alkaline pH?
Lactobacilli.
Salmonella.
Shigella.
Neisseria
Vibrio cholerae.
The causative agent/s of gas gangrene is/are:
Clostridium perfringens.
C. novyi.
С. septicum.
C. histolyticum
all are correct.
116.
A.
B.
C.
D.
E. *
117.
A.
B. *
C.
D.
E.
118.
A. *
B.
C.
D.
E.
119.
A.
B. *
C.
D.
E.
120.
A.
B.
C. *
D.
E.
121.
A. *
B.
C.
D.
E.
122.
A. *
B.
C.
D.
E.
123.
A. *
B.
C.
Which of the following properties is/are characteristic of tetanospasmin?
It is a heat-labile protein.
It is a neurotoxin.
It can be toxoided.
It is exotoxin
All of the above.
Which of the following exotoxins resembles strychnine in its effect?
Botulinum toxin.
Tetanus toxin.
Diphtheria toxin.
None of the above.
All of the above.
Which of the following bacteria most frequently cause tuberculosis in human?
Mycobacterium tuberculosis.
M. bovis.
M. africanum.
M. kansasii
All answer are correct.
Mycobacterium tuberculosis is pathogenic for:
rabbits.
guinea-pigs.
both of the above.
mice
rats
Dysentery like disease may be caused by
enteropathogenic Escherichia colt.
enterotoxigenic E. coli.
enteroinvasive E. coli.
verotoxigenic E. coli.
enteroaggregative E. coli.
Which of the following bacteria is negative for fermentation of mannitol?
Shigella dysenteriae.
S. Flexneri.
S. boydii.
S. sonnei.
All of the above.
Which of the following bacteria ferment mannitol anaerobically?
Staphylococcus aureus.
S. epidermidis.
S. saprophyticus.
S. canis
Correct answer.
Typical property of obligate anaerobes is, EXCEPT:
They generate energy by using the cytochrorne svstem
They grow best in the absence of air
They lack superoxide dismutase
D.
E.
124.
A.
B.
C.
D.
E. *
125.
A. *
B.
C.
D.
E.
126.
A.
B.
C. *
D.
E.
127.
A. *
B.
C.
D.
E.
128.
A.
B.
C. *
D.
E.
129.
A.
B.
C.
D. *
E.
130.
A.
B.
C.
D.
E. *
They lack catalase
They grow in Kitt-Tarozi medium
Which microbes can cause pus-inflamation process?
Streptococcus
Staphylococcus
Pneumococcus
Neisseria
all of these
The coagulase test is used to differentiate Staphylococcus aureus from
other staphylococci
streptococci
micrococci
enterococci
pneumococci
Which infectious agents cause food poising?
Bacillus anthracis
Clostridium tetani
Clostridium botulimum
Streptococcus pyogenes
all of these
Which infection(s) would be categorized as a zoonosis?
anthrax
gas gangrene
diphtheria
cholera
both a and b
The name 'black death' is given to which of
the following diseases?
Tuberculosis.
Diphtheria.
Plague.
AIDS.
Cholera
Which of the following tests can differentiate between classical and El Tor biotypes of Vibrio
cholerae?
Sensitivity to polymyxin B.
Agglutination of fowl RBCs.
Sensitivity to Mukerjee's group IV phage.
All of the above.
Antigenic structure
Ways of transmition of Brucellae to humans are:
direct contact with animal tissues.
ingestion of contaminated meat.
ingestion of raw infected milk.
direct contact with animal placenta
all answers are correct.
131.
A.
B.
C.
D.
E. *
132.
A.
B.
C. *
D.
E.
133.
A.
B.
C.
D.
E. *
134.
A. *
B.
C.
D.
E.
135.
A.
B.
C. *
D.
E.
136.
A.
B. *
C.
D.
E.
137.
A.
B. *
C.
D.
E.
138.
A.
B.
The causative agent/s of non-gonococcal urethritis is/are?
Chlamydia trachomatis.
Ureaplasmau urealyticum.
Mycoplasma hominis.
Herpes virus 2
All of the above.
A unique characteristic of many isolates of Pseudomonas useful in identification is
drug resistance
fecal odor
green pigment
gram staining
motility
Human brucellosis is also known as
Fran's disease
Query fever
rabbit fever
relapsing fever
undulant fever
A hard chancre is characteristic of:
primary syphilis.
secondary syphilis.
latent syphilis.
tertiary syphilis.
complication of syphilis
The causative agent of Lyme disease is:
Borrelia recurrenlis.
B. dutioni.
B. burgdorferi.
B. hermsii
B. persica
You suspect Chlamydia infection in a sexually-active young woman. Which test would be most
likely to provide results which would confirm this diagnosis?
Agglutination test for anti-cardiolipin antibodies.
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.
Francisella tularensis has no which portal of entry?
tick bite
sexual
intestinal
respiratory
only c and d
A classic symptom of pertussis is
labored breathing
convulsions
C.
D. *
E.
139.
A.
B.
C. *
D.
E.
140.
A.
B.
C. *
D.
E.
141.
A.
B.
C.
D.
E. *
142.
A.
B.
C. *
D.
E.
143.
A.
B.
C. *
D.
E.
144.
A.
B.
C.
D. *
E.
headache
paroxysmal coughing
redish of skin
The severe symptoms of pertussis are due to what effect?
irritation of the glottis by the microbe
pneumonia
damage of function of the respiratory epithelium
blocked airways
heart disease
For Escherichia coli most impotent which antigens are?
capsular
Vi
somatic
flagellar
all of these
Which of the following bacterium is causative agent of dysenteriae?
E. coli
Klebsiella
Proteus
Vibrio
Shigella
Which of the following represents a major difference between Salmonella and Shigella
infections?
incubation period
mode of transmission
place of location in intestine
presence/absence of fever and diarrhea
the portal of entry
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 purpuric. 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?
Escherichia coli.
Haemophilus influenzae.
Neisseria meningitidis.
Streptococcus agalactiae.
Streptococcus pneumoniae.
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?
Capsular polysaccharide.
Teichoic acid.
A superantigen toxin.
Lipopolysaccharide [LPS].
Plasma membrane lipids.
145.
A.
B.
C.
D.
E. *
146.
A.
B.
C. *
D.
E.
147.
A. *
B.
C.
D.
E.
148.
A.
B.
C.
D.
E. *
149.
A.
B.
C.
D. *
E.
150.
A.
B.
C.
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 α-hemolytic
Gram-positive coccus, catalasenegative. Which organism is most likely to have caused his
infection?
Streptococcus
pyogenes [Group A].
Streptococcus agalactiae [Group B].
Streptococcus bovis [Group D].
Staphylococcus aureus.
A Viridans-group Streptococcus.
. Administration of which of the following vaccines would be contra-indicated in an patient
with impaired cell-mediated immunity?
Pneumococcal vaccine (pediatric).
Pneumococcal vaccine (adult).
BCG vaccine against tuberculosis.
Tetanus toxoid.
Acellular Pertussis vaccine.
A sexually-active woman develops a urinary tract infection which ascends to the kidneys. Blood
culture yields a β-hemolytic Gram-negative rod. In this situation, which pathogen is most
common?
Escherichia coli.
Klebsiella pneumoniae.
Pseudomonas aeruginosa.
Salmonella enteritidis.
Serratia marcescens.
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?
Enteropathogenic E. coli
Balantidium coli.
Entamoeba histolytica
Giardia lamblia.
Shigella.
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?
Corynebacterium xerosis
Bordetella pertussis.
Candida albicans.
Corynebacterium diphtheriae.
Mycobacterium avium/intracellulare.
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?
Bacillus anthracis.
Bacillus cereus.
Clostridium difficile.
D. *
E.
151.
A.
B.
C. *
D.
E.
152.
A.
B.
C.
D. *
E.
153.
A.
B.
C.
D. *
E.
154.
A.
B.
C.
D. *
E.
155.
A. *
B.
C.
D.
E.
156.
A. *
B.
C.
D.
Clostridium perfringens.
Listeria monocytogenes.
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?
Group A carbohydrate.
Flagella.
M protein
Peptidoglycan.
Teichoic acid.
A child is diagnosed with Pertussis. How was this infection most likely to have been acquired?
Bite of a dog or cat.
Consumption of dairy products made from unpasteurized milk
Contact with livestock or animal products such as leather or wool.
Inhalation of respiratory droplets of another human being.
Release of oral flora into the bloodstream by dental work
Causative agent of tuberculosis is:
Staphylococus aureus
Clostridium tetani.
Bacilus subtilis
Mycobacterium tuberculosis
Mycobacterium africans
A mother is worried that the child may have contracted Lyme disease. Which finding would
most strongly suggest that she is correct?
A disseminated rash, with small papular erythematous lesions.
An ulcer and edema at the site of the tick bite.
A lesion at the site of the tick bite that develops a thick, black, crusted, scab.
A “bull’s-eye” lesion with erythematous periphery and central clearing.
A sparse red macular rash, on the palms and soles only.
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?
Monocytes/macrophages.
Basophils
Enterocytes
Erythrocytes
Neutrophils
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?
Mycoplasma pneumoniae.
Haemophilus influenzae.
Mycobacterium tuberculosis.
Streptococcus pyogenes.
E.
157.
A.
B.
C.
D. *
E.
158.
A.
B.
C. *
D.
E.
159.
A.
B.
C.
D. *
E.
160.
A.
B.
C.
D.
E. *
161.
A.
B.
C.
D. *
E.
162.
A.
Streptococcus pneumoniae.
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
The patient does not require antibiotic treatment; absence of symptoms indicates that the positive
RPR is a ‘biological false positive”.
The patient has Syphilis, but does not require antibiotic treatment, because infections with
Treponema pallidum normally resolve spontaneously.
The patient has Syphilis, but the diagnosis should be confirmed by culture before antibiotic
treatment is started.
The patient has Syphilis, and should be treated with Penicillin G
none of the above
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?
Kills enterocytes and produces ulceration and inflammation.
Paralyzes phagocytosis by neutrophils.
Blocks adsorption of nutrients by enterocytes.Stimulates ion transport by enterocytes into the
intestinal lumen.
Blocks adsorption of nutrients by enterocytes.
Causes rearrangement of the enterocyte cytoskeleton and disappearance of the brush border.
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?
Alters the actin cytoskeleton.
Inactivates ribosomes.
Proteolytic cleavage of a specific cellular protein.
Stimulates adenyl cyclase.
Stimulates guanyl cyclase.
. 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?
Transcription by bacterial RNA polymerase.
Supercoiling of bacterial DNA.
Cross-linking of peptidoglycan.
Polymerization of peptidoglycan.
Peptide bond formation by bacterial ribosomes.
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?
M-proteins.
Intact heat-killed bacteria.
Toxoids produced from superantigen toxins.
Capsular polysaccharides.
Cell-associated (C) carbohydrates.
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?
Urethral epithelium.
B.
C.
D. *
E.
163.
A.
B.
C.
D. *
E.
164.
A.
B.
C. *
D.
E.
165.
A.
B.
C.
D. *
E.
166.
A.
B.
C.
D. *
E.
167.
A.
B. *
C.
D.
E.
168.
A.
B.
C.
D. *
E.
Gall bladder.
Large intestine.
Nasopharynx.
Meninges and choroid plexus
When Bacillus anthracis is cultured, the isolate is expected to have all of the following
characteristics EXCEPT:
Formation of large colonies, which retain their shape when manipulated.
Absence of hemolysis on sheep blood agar.
Lack of motility in soft-agar testing media.
Inability to form spores.
Grampositive
Antibiotic treatment is absolutely necessary in cutaneous anthrax, to:
Prevent progression from vesicle to eschar.
Limit the amount of edema surrounding the eschar.
Prevent progression to systemic illness.
Enable the quick healing of skin lesions.
Assure that no permanent scar is formed.
The spastic paralysis of Tetanus is the effect of a protein exotoxin. Which phrase below best
describes the process directly inhibited by Tetanus toxin?
Synthesis of neurotransmitter.
Transport of neurotransmitter into vesicles.
Calcium influx required for neurotransmitter release.
Blocking and fusion of neurotransmitter vesicles with the synaptic membrane.
Binding of neurotransmitter molecules to their receptors
If you suspect Francisella infection, you should inform the lab when sending a specimen. What
is the predominant reason you need to do this?
Francisella requires culture in living human cells.
Francisella requires culture in living protozoa, such as amoebae.
Francisella although biologically Gram-negative, stains Gram-positive unless special technique is
used.
Francisella is readily transmitted to laboratory workers when cultured.
Francisella cannot be cultured on ‘standard media’.
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 membrane-bounded inclusion body, within the nucleus.
A membrane-bounded inclusion body, within the cytoplasm.
Rod shaped Gram-positive bacilli, free within the cytoplasm.
Gram-negative cocci, within the lumen of the endoplasmic reticulum.
Cyst forms inside lysosomes.
An infant is brought to the emergency room, cyanotic and with poor muscle tone.
Which condition is most likely given these findings?
Antibiotic-associated colitis.
Diphtheria.
Anthrax.
Botulism.
Tetanus.
169.
A.
B.
C. *
D.
E.
170.
A. *
B.
C.
D.
E.
171.
A.
B.
C.
D.
E. *
172.
A.
B. *
C.
D.
E.
173.
A. *
B.
C.
D.
E.
174.
A.
B.
C. *
D.
E.
175.
A.
B. *
In what way do Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae
most closely resemble each other?
Lipopolysaccharide in their outer membranes.
Teichoic acid in their envelopes.
Polysaccharide capsules
Thick peptidoglycan in their cell walls.
Motility due to flagella.
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?
Dog tick.
Mosquito of the genus Anopheles.
Blood-sucking sandfly.
Flea.
Human body louse.
The cell tropism of the genus Rickettsia determines the type of disease produced. Which phrase
best describes Rickettsial disease?
Encephalitis
Meningitis.
Myocarditis
Myositis.
Vasculitis.
Which characteristic of Mycobacterium tuberculosis is believed to be most essential to its
transmission?
Anti-phagocytic polysaccharide capsule.
Impermeable lipid-rich envelope.
Production of protein exotoxins.
Rapid growth.
Type III secretion system.
In a patient with systemic febrile illness, which item in the history would indicate the highest
risk for Brucella infection?
Contact with livestock or animal products.
Recent travel to China.
Chronic cardiopulmonary disease.
Age less than two years.
Drinking unpurified water from a river or stream.
A patient becomes infected with Salmonella enterica serotype typhi. Which condition would
most strongly favor development of a “chronic carrier state” with this organism?
Age over 70 years.
Infection via the respiratory route.
Gallstones.
Kidney stones.
Chronic pulmonary disease.
A patient has an abscess from which Bacterioides fragilis is isolated. Which condition is most
likely to have facilitated infection by this organism?
Treatment with trimethoprim/sulfa.
Tissue ischemia.
C.
D.
E.
176.
A.
B.
C.
D. *
E.
177.
A.
B.
C.
D. *
E.
178.
A.
B. *
C.
D.
Presence of neutrophils.
Antibiotic treatment for another bacterial infection.
Colonization of the large intestine with spores of this organism.
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?
Aids in acquisition of iron.
Toxic to lung epithelial cells
Identical to human polysaccharide, so is non-immunogenic.
Reduces phagocytosis by neutrophils.
Inhibits activation of Complement.
A patient has a peptic ulcer. Which organism is most likely to have created this lesion?
Campylobacter jejuni.
Enterococcus faecalis.
Escherichia coli.
Helicobacter pylori
Salmonella enteritidis.
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?
E.
179.
A.
B. *
C.
D.
E.
180.
Colonization of her large intestine by antibiotic-resistant E. coli.
Alteration of her intestinal flora by antibiotic treatment.
none of the above
An allergic response to her antibiotic treatment.Acquisition of an antibiotic-resistance plasmid
(R-Factor) by C. difficile.
Acquisition of an antibiotic-resistance plasmid (R-Factor) by C. difficile.
Chancroid is caused by
Treponema pallidum
Hemophilus ducreyi
Treponema pertenua
Clostridium sp.
Mycoplasma
The symptom of secondary syphilis is
A.
B.
C.
D. *
E.
181.
A.
B. *
C.
D.
neurological problems
giant lesions affecting many internal organs
a hard-based, painless chancre
a rash covering all parts of the body
Meningitis
Which of the following statements best describes Streptococcus pneumoniae?
bile soluble, catalase positive,
bile soluble, capsulated
bile soluble, gramnegative, optochin resistant
bile soluble, catalase positive, optochin sensitive
E.
182.
A.
B.
C. *
D.
E.
183.
A.
B. *
C.
D.
E.
184.
A.
B.
C.
D. *
E.
185.
A. *
B.
C.
D.
E.
186.
A.
B.
C.
D.
E. *
187.
A.
B. *
C.
D.
E.
188.
A.
B.
C. *
D.
E.
189.
A.
bile soluble, catalase negative, motily
Which of the following is a pathogen of the oropharynx?
Streptococcus faecalis
Streptococcus pneumoniae
Streptococcus pyogenes
Streptococcus bovis
Streptococcus viridans
What do endotoxins and exotoxins have in common?
secreted into the medium
cause damage to the host
heat stable
heat resistent
contain polysaccharide
Which virulence factor results in the symptoms of Staphylococcal food poisoning?
exfoliative exotoxin
hyaluronidase
endotoxin
enterotoxin
neurotoxin
Which of the following best describes the pathogenesis of acute rheumatic fever?
characterized by inflammation of the heart and/or the joints
due to an immunologic cross reaction between heart muscle and Staphylococcus aureus
involves B-hemolytic Streptococci growing in the heart
is a complication of Group A Streptococcal skin disease as well as pharyngitis
tonsilitis is first stage of development of rheumatic fever
Which of the following statements about gonorrhea is true?
Men are frequently asymptomatic carriers.
Bacteremia is common.
Serologic diagnosis is more reliable than culture.
Penicillins are no longer recommended for treatment.
Gonococci are within leucocytes in a sample
Gonococci are within leucocytes in a sample
growth in 6.5% NaCl
oxidase positive
catalase negative
PYR positive
motility
Which of the following tests may be used to differentiate Salmonella typhi from Shigella
species?
glucose fermentation
gas production from glucose
motility
citrate utilization
color of colonies on Endo medium
Which of the following descriptions best fits a typical strain of Escherichia coli?
non-motile, aerogenic, lactose fermenting mucoid colony
B.
C. *
D.
E.
190.
A.
B. *
C.
D.
E.
191.
A.
B. *
C.
D.
E.
192.
A.
B.
C. *
D.
E.
193.
A.
B. *
C.
D.
E.
194.
A.
B. *
C.
D.
E.
195.
A.
B.
C.
D. *
E.
196.
A. *
B.
C.
D.
motile, anaerogenic, non-lactose fermenting, indole positive
motile, aerogenic, lactose fermenting, indole positive
motile, aerogenic, non-lactose fermenting, citrate negative
non-motile, ferments lactose slowly, gramnegative
Hemolytic uremic syndrome is caused by which of the following bacterium?
Campylobacter jejuni
Escherichia coli 0157
Helicobacter pylori
Salmonella typhi
Ureaplasma
What is the most common cause of urinary tract infections?
Staphylococcus saprophyticus
Escherichia coli
Enterococcus fecalis
Streptococcus bovis
Staphylococcus epidermidis
Which of the following result(s) best describe(s) the listed organism?
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
What term refers to a disease that is always out there in low numbers in a given regional area?
pandemic
endemic
epidemic
hypodermic
case
Which of the following tests may be used to differentiate Salmonella paratyphi from Shigella
species?
Fermentation of glucose
gas production from glucose
gram staining
citrate utilization of Simmons’ citrate agar
shape
Which of the following descriptions best fits a typical strain of Escherichia coli?
motile, aerogenic, non-lactose fermenting, citrate negative
non-motile, aerogenic, lactose fermenting mucoid colony
motile, anaerogenic, non-lactose fermenting, indole positive
motile, aerogenic, lactose fermenting, indole positive
motile, anaerogenic, lactose fermenting, sporulated
Which one of the following enterobacteriaceae always are causative agents of enteric diseases?
Shigella
Serratia
Klebsiella
Citrobacter
E.
197.
A.
B.
C. *
D.
E.
198.
A. *
B.
C.
D.
E.
199.
A.
B. *
C.
D.
E.
200.
A.
B.
C. *
D.
E.
201.
A.
B.
C.
D. *
E.
202.
A.
B.
C.
D.
E. *
203.
A.
B.
C. *
D.
E.
204.
A.
Proteus
Syphilis is caused by which of the following?
Helicobacter pylori
Proteus mirabilis
Treponema pallidum
Serratia marcesans
Treponema Vincentii
Borellia burgdorferi causes which disease?
Lyme's Disease
Rocky Mountain Spotted Fever
Hanta
Rabies
Relapsing fever
How is leptospirosis, caused by Leptospira interrogans, transmitted?
Tick bite
Contaminated urine in food or water
Undercooked meat
Inhaled aerosol
louse feces
What is the most common human pathogen/opportunist?
Staphylococcus aureus
Steptococcus pneumoniae
Pseudomonas aeruginosa
Escherichia coli
Enterococcus
Brucella abortussis, a cause of undulant fever, is transmitted in all but which of the following
ways?
none of the above
Direct contact with infected animals
Exposure to animal carcass
Exposure to animal feces
Drinking unpasteurized milk
Which of the following is NOT true about Bordetella pertussis?
none of the above
Causes Whooping Cough
Attaches to ciliated cells with capsules
Complications can include pneumonia, brain damage and death
Gram negative anaerobe
Which of the following is NOT true of Neisseria gonorrhea?
produces endotoxin
Is a mucosal pathogen
Produces exotoxin
Can disseminate in the immunosuppressed
Complications include ectopic pregnancy, PID and sterility
Which of the following is NOT true of Neisseria meningitidis?
none of the above
B.
C. *
D.
E.
205.
Crosses the blood brain barrier
Has 3 serotypes - A, B, Y
Colonizes nasopharynx
Predisposed groups include diabetics
Helicobacter pylori, a cause of peptic ulcers and gastric carcinoma, is diagnosed by which of
the following methods?
A.
B.
C.
D.
E. *
206.
A.
B. *
C.
D.
E.
207.
A.
B.
C. *
no correct answer
Serology (serum) test
Biopsy (invasive)
Radioactive isotope C14 test
All are correct
What is the cause of food toxic poisoning?
Clostridium tetani
Clostridium botulinum
Salmonella enteriditis
Escherichia coli
Campylobacter jejuni
Which of the following members of the Vibrio family cause severe dehydration?
none of the above
Vibrio vulnificus
Virbrio cholerae
D.
Vibrio parahaemolyticum
E.
208.
Vibrio alginolyticus
What is the incubation period for Shigella dysenteriae?
A.
B.
C.
D. *
E.
209.
none of the above
6 to 8 hours
24 to 48 hours
2 to 4 days
1 to 2 weeks
Which of the following does not occur when an individual is infected with Salmonella
enteriditis?
all
Endotoxins cause inflammation and fever
Enterotoxins cause diarrhea
Cytotoxins lyse endothelial cells lining the intestinal tract
Proteolytic enzymes cause necrosis
What is the primary cause of death from Salmonella typhi (Typhoid fever)?
none of the above
Hemorrhaging necrosis
DIC (disseminating intravascular coagulation)
Toxemia
High fever
A.
B.
C.
D.
E. *
210.
A.
B. *
C.
D.
E.
211.
A.
B.
C.
D. *
E.
212.
A.
B.
C.
D. *
E.
213.
A.
B.
C.
D.
E. *
214.
A. *
B.
C.
D.
E.
215.
A. *
B.
C.
D.
E.
216.
A. *
B.
C.
D.
E.
217.
A. *
B.
C.
D.
E.
218.
Yersinia pestis causes both the Bubonic Plague and the more deadly Pneumonic Plague. How is
Pneumonic Plague transmitted?
The bite of lice
The bite of a flea
Via rodents
Air-borne
Exchange of bodily fluids
Which of the following is NOT true about Mycoplasma hominis?
none of the above
Synonymous with Ureaplasma urealyticum
More prevalent in late summer/early fall
Vaccine uses conjugated polysaccharide B
Is endemic worldwide
Which of the following bacteria is/are primarily human pathogens?
Salmonella typhi.
S. Paratyphi A.
S. Paratyphi B.
Shigella
All answers are correct.
Which of the following media is/are used for blood culture in cases of enteric fever?
Bile broth.
Tetrathionate broth.
Selenite-F broth.
Sugar broth.
All answers are correct.
For determining the serotype of infecting organism, detection of which agglutinins is more
important in Widal test?
O.
H.
Fimbrial.
M.
Vi
Bipolar staining is characteristic of:
Yersinia pestis.
Proteus mirabilis.
Pseudomonas aeruginosa.
Vibrio cholerae
Bacillus anthracis
Scalded skin syndrome is due to which toxin of Staphylococcus aureus?
Exfoliatin
Enterotoxin.
Leucocidin.
Haemolysin
Necrotoxin
Isolation of pneumococci from clinical specimens may be attempted by intraperitoneal
inoculation
A.
B.
C. *
D.
E.
219.
A. *
B.
C.
D.
E.
220.
A.
B.
C.
D. *
E.
221.
A.
B.
C. *
D.
E.
222.
A.
B.
C. *
D.
E.
223.
A. *
B.
C.
D.
E.
224.
A. *
B.
C.
D.
E.
225.
A. *
B.
C.
D.
rabbits.
rats
mice.
sheeps.
horses
Which biotype/s of Corynebacterium diphtheriae ferment/s starch and glycogen?
Gravis.
Intermedius.
Mitis
All of the above.
none of the above
Diphtheria toxin has a special affinity for which of the following tissue/s?
Heart muscles.
Nerve endings.
Adrenal glands.
All are correct
no correct answer
“Medusa head” appearance of the colonies is characteristic of:
Proteus mirabilis.
Clostridium tetani.
Bacillus anthracis.
Pseudomonas aeruginosa.
Clostridium botulini
Typical drumstick appearance of bacilli is observed in:
C. diphtheriae
Clostridium perfringens.
С. tetani
C. histolyticum.
C. difficilae
Pneumonic plague can be transmitted from man to man by:
droplet infection.
inoculation.
ingestion.
flea bite
all are correct
Common reservoir host/s of Brucella melitensis is/are:
sheep and goats.
cattle.
pigs.
dogs
all of the above.
Which of the following organisms may lead to pseudomembrane formation in the throat?
Corynebaclerium diphtheriae
Treponema Vinsentii
Streptococcus pyogenes.
Candida albicans.
E.
226.
A.
B.
C. *
D.
E.
227.
A. *
B.
C.
D.
E.
228.
A.
B. *
C.
D.
E.
229.
A.
B.
C. *
D.
E.
230.
A.
B.
C.
D.
E. *
231.
A.
B.
C.
D.
E. *
232.
A.
B. *
C.
D.
E.
233.
A.
B.
All of the above.
All of the following bacteria can cause food poisoning, EXCEPT
Salmonella enteritidis.
Staphylococcus aureus.
Clostridium tetani
Clostridium botulinum
Listeria monocytogenes
A positive Mantoux test is indicated by an area of induration of:
10 mm or more in diameter.
5-9 mm in diameter.
3-4 mm in diameter.
1-2 mm in diameter
none of the above.
Traveller's diarrhoea is caused by:
enteropathogenic Escherichia coli.
enterotoxigenic E. coli.
enteroinvasive E. coli.
enterohaemorrhagic E. coli.
enteroaggregative E. coli.
Which of the following bacteria is more resistant to unfavorable environmental conditions?
Shigella dysenteriae.
S. flexneri.
C. tetani
S. sonnei.
C. albicans
In enteric fever, Salmonella may be isolated from:
urine.
faeces.
blood.
bile
all of the above.
Which of the following serotypes of Salmonella can cause gastroenteritis?
S. Enteritidis.
S. Newport.
S. Typhimurium.
S. cholerae suis
All are correct.
Plague is transmitted by:
sandflies.
rat fleas.
mites.
ticks.
louse
Bubonic plague can be diagnosed in the laboratory by:
demonstration of gram-negative coccobacilli.
culture on blood agar.
C.
D.
E. *
234.
A. *
B.
C.
D.
E.
235.
A.
B. *
C.
D.
E.
236.
A.
B.
C. *
D.
E.
237.
A.
B.
C. *
D.
E.
238.
A. *
B.
C.
D.
E.
239.
A.
B. *
C.
D.
E.
240.
A. *
B.
C.
D.
E.
inoculation in guinea-pigs.
inoculation in rats
all of the above.
Most strains of Staphylococcus aureus show:
a golden-yellow pigment.
β-haemolysis on sheep blood agar.
phosphatase production.
novobicin resistance
all of the above.
Thin, slender and gram-positive bacilli possessing metachromatic granules and showing
Chinese letter arrangement are characteristic of:
Mycobacterium tuberculosis.
Corynebacterium diphtheriae.
Bacillus anthracis.
Clostridium perfringens.
Bordetella pertussis
A positive Schick test implies that the person is:
healthy
immune and non-hypersensitive
susceptible and non-hypersensitive.
immune and hypersensitive.
non-immune and hypersensitive.
Malignant pustule is characteristic of:
.relapsing fever
pulmonary plage
cutaneous anthrax
leptospirosis
all of the above.
Cholera toxin resembles which of the following toxins?
Labile toxin of Escherichia coli.
Stable toxin of E. coli.
Diphtheria toxin.
Tetanus toxin.
Staphylococcus enterotoxin
Which of the following Brucella spp. is most pathogenic for man?
B. abortus
B. melitensis.
B. suis.
B. canis.
B. ovis
In which of the following sexually transmitted diseases, ulcer/s is/are painless?
Syphilis.
Chancroid.
Herpes genitalis.
None of the above
All of the above.
241.
A.
B.
C. *
D.
E.
242.
A.
B. *
C.
D.
E.
243.
A.
B.
C.
D.
E. *
244.
A. *
B.
C.
D.
E.
245.
A. *
B.
C.
D.
E.
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?
Mycoplasma pneumoniae.
Chlamydia pneumoniae
Haemophilus influenzae.
Escherichia coli.
Streptococcus pneumoniae
A lactose-fermenting Gram-negative rod is isolated from the bloody stool of a young child.
Which pathogen is most likely?
Salmonella enterica
Escherichia coli.
Vibrio cholerae
Shigella dysenteriae
Clostridium difficile
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...
Borrelia burgdorferi
Chlamydia pneumoniae
Franciscella tularensis
Yersinia pestis.
Rickettsia rickettsii
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?
Yersinia pestis.
Helicobacteri pylori.
Franciscella tularensis
Coxiella burnetii
Klebsiella pneumoniae
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?
Mycoplasma pneumoniae.
Haemophilus influenzae.
Mycobacterium tuberculosis
Corynebacterium diphtheriae
Streptococcus pneumoniae.
246.
A.
B. *
C.
D.
E.
247.
A.
B.
C.
D. *
E.
248.
A.
B.
C.
D.
E. *
249.
A.
B.
C.
D. *
E.
250.
A.
B. *
C.
D.
E.
251.
A.
B.
C. *
D.
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?
Escherichia coli.
Staphylococcus epidermidis.
Streptococcus pneumoniae.
Pseudomonas aeruginosa
Haemophilus influenzae
Which of the following bacteria can be successfully cultured on cell-free medium?
Chlamydia trachomatis
Coxiella burnetii
Mycobacterium leprae
Mycoplasma pneumoniae
Rickettsia prowazekii.
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?
Streptococcus pyogenes (Group A)
Streptococcus agalactiae (Group B)
Streptococcus mitis
Streptococcus bovis (Group D)
Streptococcus pneumoniae
. 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?
Streptococcus pyogenes
Streptococcus agalactiae
Streptococcus mitis
Staphylococcus aureus
Staphylococcus epidermidis
Vacationer develops watery diarrhea but not chills or fever. In this setting which of the
following pathogens is the most common?
Salmonella enterica
Escherichia coli
Staphylococcus aureus
Campylobacter jejuni
Helicobacter pylori
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?
Pseudomonas aeruginosa
Klebsiellla pneumoniae
Escherichia coli
Staphylococcus saprophyticus
E.
252.
A.
B.
C. *
D.
E.
253.
A.
B.
C.
D. *
E.
254.
A.
B.
C.
D.
E. *
255.
A.
B. *
C.
D.
E.
256.
A.
B.
C.
D.
Enterobacter, sp.
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?
Streptococcus pneumoniae.
Haemophilus influenzae.
Corynebacterium diphtheriae.
Bordetella pertussis.
Mycobacterium avium/intracellulare.
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.
What is the most likely organism?
Bacteroides fragilis
Campylobacter fetus
Eschericahia coli
Pseudomonas aeruginosa
Citrobacter spp.
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 Gram-positive 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 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
in peritoneal exudate?
Salmonella typhi
Clostridium tetani
Clostridium perfringens
Pseudomonas aeruginosa
Bacteroides fragilis
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?
Colon
Nose
Throat
Vagina
All of the above
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 probable?
Pseudomonas aeruginosa
Klebsiella pneumoniae
Haemophilus influenzae
Neisseria gonorrhoeae
E. *
257.
A.
B.
C.
D. *
E.
258.
A.
B.
C. *
D.
E.
259.
A.
B.
C.
D. *
E.
260.
A.
B. *
C.
D.
E.
261.
A.
B.
C. *
D.
E.
262.
A.
B.
C.
D. *
E.
263.
A. *
B.
C.
Neisseria meningitidis
Each of the statements about the classification of streptococci is correct EXCEPT:
Pneumococci {Streptococcus pneumoniae) are alpha-hemolytic and can be serotyped on the basis of
their polysaccharide capsules
Enterococci are group D streptococci and can be classified by their ability to grow in 6.5% sodium
chloride
Although pneumococci and the viridans streptococci are alpha-hemolytic, they can be differentiated
by the bile solubility test and their susceptibility to optochin
Viridans streptococci are identified by Lance-field grouping, which is based on the C carbohydrate in
the cell wall
All of the above
Each of the following agents is a recognized cause of diarrhea EXCEPT:
All answers are right
Clostridium perfringens
Enterococcus faecalis
Escherichia coli
Vibrio cholerae
Each of the following organisms is an important cause of urinary tract infections EXCEPT:
Escherichia coli
Proteus mirabilis
Klebsiella pneumoniae
Bacteroides fragilis
All of the above
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?
Clostridium difficile
Streptococcus pyogenes
Shigella dysenteriae
Salmonella enteritidis
All of the above
Each of the following statements concerning Mycobacterium tuberculosis is correct EXCEPT:
After being stained with carbolfuchsin, M. tuberculosis resists decolorization with acid alcohol
M. tuberculosis has a large amount of mycolic acid in its cell wall
M. tuberculosis appears as a red rod in Gram-stained specimens
M. tuberculosis appears as a red rod in acid-fast stained specimens
All of the above
A 50-year-old man has a fever and is coughing up. The patient has contacted with pigeons.
Which one of the following microorganism is MOST likely to be the cause?
Listeria monocytogenes
Clostridium
perfringens
Peptostreptococcus intermedins
Chlamydia psittaci
Fusobacterium nucleatum
Which one of the following diseases is BEST diagnosed by serologic means?
Q fever
Pulmonary tuberculosis
Gonorrhea
D.
E.
264.
A.
B.
C.
D.
E. *
265.
A.
B. *
C.
D.
E.
266.
A.
B.
C. *
D.
E.
267.
A. *
B.
C.
D.
E.
268.
A.
B.
C. *
D.
E.
269.
A.
B.
Actinomycosis
All answers are right
A group of medical students developed nausea, vomiting, and abdominal cramping a few hours
after eating sandwiches and potato salad at the school cafeteria. They had no diarrhea. By the
next morning they were fatigued but recovered.
Which organism is most likely to have caused their illness?
Salmonella typhi
Borrelia burgdorferi
Clostridium botulinum
Clostridium perfringens
Staphylococcus aureus
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?
Neisseria meningitidis
Neisseria gonorrhoeae.
Haemophilus ducreyi.
Mycoplasma hominis
Treponema pallidum.
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?
Skin
Colon
Oropharynx
Urethra
Nasopharynx
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 in chain. If you found the catalase test to be negative, which one of the
following organisms would you MOST probably have isolated?
Streptococcus pyogenes
Staphylococcus aureus
Staphylococcus epidermidis
Streptococcus pneumoniae
All of the above
The coagulase test, in which the bacteria cause
plasma to clot, is used to distinguish
Streptococcus pyogenes from Enterococcus faecalis
Streptococcus pyogenes from Staphylococcus aureus
Staphylococcus aureus from Staphylococcus epidermidis
Staphylococcus epidermidis from Neisseria meningitidis
All of the above
Which one of the following is considered a virulence factor for Staphylococcus aureus?
A heat-labile toxin that inhibits glycine release at the internuncial neuron
An oxygen-labile hemolysin
C.
D. *
E.
270.
A.
B.
C.
D. *
E.
271.
A.
B.
C. *
D.
E.
272.
A.
B.
C.
D. *
E.
273.
A.
B.
C.
D. *
E.
274.
A.
B. *
C.
D.
E.
275.
A.
B. *
C.
D.
E.
276.
A.
Resistance to novobiocin
Protein A that binds to the Fc portion of IgG
All are correct
The MOST important protective function of the antibody stimulated by tetanus immunization
is
To prevent formation of endotoxin by the pathogen
To opsonize the pathogen (Clostridium tetani)
To prevent growth of the pathogen
To neutralize the toxin of the pathogen
All of the above
Five hours after eating fried rice at a restaurant, a 24-year-old woman and her husband both
devel oped nausea, vomiting, and diarrhea. Which of the following organisms is the MOST
likely to be involved?
Clostridium perfringens
Enterotoxigenic Escherichia coli
Bacillus cereus
Salmonella typhi
All are right
For which one of the following enteric illnesses is a chronic carrier state MOST likely to
develop?
Campylobacter enterocolitis
Shigella enterocolitis
Cholera
Typhoid fever
All
The most important benefit that the human gastrointestinal flora provide for their host is
digestion of dietary cellulose
a low grade toxemia
production of dietary protein
antagonism against colonization by potential pathogens
production of antibodies
The main carrier site on the human body for strains of potentially pathogenic Staphylococcus aureus
is the
oral cavity
throat (posterior nasopharynx)
nasal membranes
gastrointestinal tract
vagina
Each of the following statements concerning Mycobacterium leprae is correct EXCEPT:
In lepromatous leprosy, large numbers of organisms are usually seen in acid-fast-stained smears
The organism will grow on bacteriologic media in 3-6 weeks
Prolonged therapy (9 months or longer) is required to prevent recurrence
Skin tests for delayed hypersensitivity are useful diagnostically
Nine bandad armandrilo may be inoculated with lepra bacilli
The carrier site in humans for pathogenic Neisseria meningitidis is the
conjunctiva
B. *
nasopharynx
C.
D.
E.
277.
urogenital tract
blood
meninges
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.
B.
C.
D.
E. *
278.
A.
B.
C. *
D.
E.
279.
Lactobacillus acidophilus
Pseudomonas aeruginosa
Escherichia coli
Vibrio cholerae
Helicobacter pylori
Silver nitrate or an antibiotic is put into the eyes of newborn infants to prevent infection by
Doderlein's bacillus (Lactobacillus acidophilus)
Herpes simplex virus
Neisseria gonorrhoeae
Chlamydia trachcomatis
two of the above
A characteristic of Streptococcus mutans that allows it to initiate dental plaque and dental caries is:
A.
B.
C.
D. *
E.
280.
the ability to attach specifically to the pellicle of the tooth
the ability to utilize sucrose as a source of carbon and energy
the ability to produce a dextran capsule
the ability to produce lactic acid
all of the above
The fimbriae of enterotoxigenic E. coli are essential to the bacterium when it causes disease because
A. *
B.
they are needed for initial attachment of the bacteria to the gastrointestinal epithelium
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
symptoms of disease
E.
A.
they allow the bacteria to swim "upstream" against the peristaltic action of the GI tract thereby
remaining established in the GI tract
The fibrin coat that can be formed by coagulase-positive staphylococci and the hyaluronic acid
capsule of Streptococcus pyogenes are pathogenic strategies to
promote colonization of a host
B.
cause direct damage to host cells during pathogenesis
C.
hide bacterial antigens from the host immune tissues
D. *
E.
survive as intracellular parasites
alter or change their surface antigens within the course of an infection
281.
282.
Leukocidins are
A.
B.
C.
D.
E. *
283.
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 leucocytes
The streptococcal invasin which behaves as a "spreading factor" by breaking down the framework of
connective tissues is called
A.
B.
collagenase
streptokinase
C.
streptolysin
D.
E. *
284.
erythrogenic toxin (pyogenic exotoxin
hyaluronidase
. A primary determinant of virulence in Streptococcus pyogenes, which is involved in adherence,
resistance to phagocytosis and antigenic variation, is
A.
B.
C. *
D.
E.
streptokinase
lipopolysaccharide (endotoxin)
M-protein
coagulase
Protein A
285.
Which of the following statements that relate to bacterial exotoxins and endotoxins is true?
A. *
B.
C.
Exotoxins are proteins; endotoxins are lipopolysaccharides
Exotoxins are typically structural (cell wall) components of Gram-positive bacteria
Endotoxins can never be released by the cells that produce them.
D.
Endotoxins cause their toxicity through an enzymatic mechanism of action.
E.
286.
A.
B.
C.
D.
E. *
287.
A.
In the host, endotoxins are destroyed by the enzyme lysozyme.
The substrate for the enzymatic (A) component of diphtheria toxin is
NAD
cyclic AMP
the regulatory proteins of the eukaryotic adenylate cyclase complex
ATP
elongation factor 2 (EF-2)
Why does the large volume of fluid lost by diarrhea during infection with Vibrio cholerae
is a consequence of fluid replacement during treatment of the disease and does not result directly
from activity of the cholera toxin
results from electrolytes binding to the intestinal enterocytes which upsets their water retention
capability
B.
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.
288.
results from neurotoxic effects of the cholera toxin on the central nervous system
The similarity between the toxic shock syndrome toxin (TSST), the staph enterotoxins, and the
erythrogenic toxin (pyogenic exotoxin) is
A.
B. *
they are all produced by Staphylococcus aureus
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.
289.
they are the same (identical) toxin produced by three different organisms
Both the botulinum toxin and the tetanus toxin
A.
B.
C. *
are produced by Bacillus anthracis
act in the central nervous system
act in the peripheral nervous system
D.
E.
290.
are Zn++ dependent protease enzymes
two of the above
Which tissue in a human is free from colonization by microbes (normal flora) because the organisms
lack normal access to the tissue?
A. *
B.
blood (vascular system)
colon
C.
D.
E.
291.
stomach
lower respiratory tract
urinary tract (urethra)
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. *
C.
lower respiratory tract (lungs)
upper gastrointestinal tract
D.
lower gastrointestinal tract
E.
292.
A.
B.
vagina
The predominant bacteria in the mouth, GI tract (colon), and skin, respectively, are
staphylococci, streptococci, and corynebacteria
streptococci, E. coli, and staphylococci
C. *
D.
lactic acid bacteria, Bacteroides, and staphylococci
staphylococci, E. coli, and streptococci
E.
293.
neisseriae, enterococci, and clostridia
The predominant bacterium in the GI tract of nursing infants, because mother's milk contains a
growth factor that enriches for bacterial growth, is
A.
B.
Enterococcus faecalis
Escherichia coli
C.
D.
E. *
294.
A.
B.
Bacteroides fragilis
Lactobacillus acidophilus
Bifidobacterium bifidum
The most important benefit that the human gastrointestinal flora provide for their host is
digestion of dietary cellulose
production of endotoxin that produces toxemia
C.
D. *
E.
295.
production of dietary protein
antagonism against colonization by potential pathogens
production of antibodies
The bacterial product that prevents colonization of the vagina by potentially pathogenic yeasts is
A.
B.
C.
D.
E. *
296.
bacteriocin
peroxide
TSST toxin
lysozyme
lactic acid
The main carrier site on the human body for strains of potentially pathogenic Neisseria meningitidis
is the
A.
B. *
C.
nasal membranes
throat (posterior nasopharynx
oral cavity
D.
E.
297.
gastrointestinal tract
vagina
In the pathogenesis of Helicobacter pylori what is the colonization site in the host?
A.
B. *
nasal sinuses
stomach
C.
D.
lower intestine
throat
E.
298.
A.
respiratory tract
What is the colonization site of Corynebacterium diphtheriae, the agent of diphtheria?
skin
B.
urethra
C.
eye
D. *
E.
299.
A.
B.
C.
D. *
throat
none of the above
Characteristics of Streptococcus mutans which allow it to initiate dental caries include
the ability to attach specifically to the pellicle of the tooth
the ability to produce lactic acid from sucrose, glucose and fructose
the ability to form and grow in a biofilm on the enamel of the tooth
all are correct
E.
300.
none of the above
A determinant of virulence of Streptococcus pneumoniae which allows the bacteria to resist
engulfment by phagocytes is
A.
fimbriae
B. *
C.
a polysaccharide capsule
coagulase
D.
E.
301.
production of TSST exotoxin
neuraminidase
The fimbriae of pathogenic Neisseria gonorrhoeae are apparently essential to the bacterium when it
produces the disease gonorrhea because
A. *
B.
C.
D.
they are responsible for initial attachment of the bacteria to the urethral or cervical epithelium
they cause the production of pus which is characteristic of gonorrhea
they make the bacteria resistant to phagocytic killing and digestion by white blood cells
they convert urinary tract components (urine) to substances which provoke symptoms of disease
E.
302.
A.
B.
C. *
D.
E.
303.
A.
B.
they allow the bacteria to swim "upstream" against the flow of urine and thereby remain established
in the urinary tract
Which bacterial invasin is mismatched with its activity in the host?
staphylokinase: degrades fibrin
coagulase: clots fibrin
hyaluronidase: degrades the ground substance of connective tissue
streptolysin: lyses neutrophil membranes
none of the above
The clostridial invasin that dissolves the framework of muscle is
botulinum toxin
tetanus toxin
C. *
hyaluronic acid
D.
E.
collagenase
neuraminidase
304.
Choose among listed the part of anthrax toxin:
A.
Leukocidin
B.
Enterotoxin
C.
D. *
Haemolysin
Edema toxin
E.
305.
Tetanospasmin
Leukocidins are
A.
B.
enzymes contained in the lysosomes of phagocytes to kill ingested bacteria
proteins produced by bacteria that kill closely-related bacteria
C.
D.
E. *
306.
proteases produced by bacteria which destroy host immunoglobulins
superantigens produced by Staphylococcus aureus
substances produced by pyogenic bacteria that kill phagocytes
Which of the following statements about bacterial endotoxins is true?
A.
B. *
C.
D.
They usually act at a tissue site in the host that is removed from the site of bacterial growth
They are nonantigenic.
They typically have an enzymatic (specific) type of activity
They can be converted into toxoids.
E.
307.
A.
B.
C.
D. *
E.
308.
none of the above
Bacterial endotoxins and exotoxins both share this property.
They are proteins
They are structural components of the bacterial cell wall
They have an enzymatic type of activity
They are toxic to animals.
none of the above
Which of the following statements characterizes the mechanism of action of diphtheria toxin?
A. *
B.
C.
inhibits protein synthesis in susceptible cells
causes an increase in cAMP in cells resulting in severe edema
causes an increase in cAMP in cells leading to diarrhea
D.
E.
309.
interferes with the transmission of neurotransmitters at stimulatory neuromuscular synapse
interferes with secretion of neurotransmitters at an inhibitory neural synapse in the central nervous
system
Both the botulinum toxin and the tetanus toxin are
A.
B.
C.
superantigens
enterotoxins
adenylate cyclase enzymes
D. *
protease enzymes
E.
310.
A. *
B.
C.
D.
none of the above
Mechanism of action of tetanotoxin?
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
E.
311.
A.
B. *
cleave neuraminic acid in the intercellular space
Both the cholera toxin and the E. coli LT toxin
have an A+B subunit arrangement
are identical in their primary structure
C.
D.
E.
312.
are ADP-ribosylating toxins
have an enzymatic mechanism of action
all of the above
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. *
C.
D.
E.
313.
cause fluid and electrolyte imbalance
cleave host cell membranes
act as superantigens to trigger an overwhelming immunological reaction
initiate a localized inflammatory response in the intestine
The portion of the bacterial lipopolysaccharide (LPS) that is responsible for the toxicity of the
molecule is
A. *
B.
C.
D.
E.
314.
lipid A
lipoteichoic acid
O polysaccharide
Omp A
N-acetylglucosamine (NAG)
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.
Capsulare
C. *
D.
E.
315.
O polysaccharide
R antigen
H antigen
What bacterial structure or substance is primarily associated with antigenic variation in the Group A
streptococci?
A.
outer membrane protein (omp)
B.
streptokinase
C.
D. *
E.
316.
hyaluronic acid capsule
Polysaccharide
M-protein
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. *
C.
D.
E.
317.
beta lactam antibiotics are ineffective against Gram-negative bacteria
the lysis of bacterial cells increases the activity of bacterial LPS
Complement activation cannot occur in the presence of the antibiotic
the antibiotic suppresses the immune response necessary to eliminate the pathogen
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.
B.
C.
D. *
E.
318.
A.
B.
C.
D. *
E.
319.
Streptococcal streptolysin
Salmonella LPS (endotoxin
Pseudomonas Exotoxin A
Staphylococcal toxic shock syndrome toxin
E. coli O157 H:7 shiga toxin
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
foxoid administration
Active artificial immunity to diphtheria is accomplished by
A.
B. *
C.
D.
E.
320.
A.
B.
C.
D.
E. *
321.
diphththeria antitoxin (antiserum) administration
vaccination with diphtheria toxoid
recovery from the disease diphtheria
all of the above
none of the above
Which test you can use for detect in patient latent Syphilis?
Gram stain of material from a skin lesion.
Physical exam to detect characteristic neurological symptoms.
. Dark field microscopy of CSF.
Culture of the organism from blood and CSF.
Tests for ‘non-treponemal’ and ‘anti-treponemal’ antibodies in serum.
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?
Colon
A.
B.
C. *
D.
E.
322.
A.
B.
C.
D.
E. *
323.
A.
B.
C. *
D.
E.
324.
A.
B. *
C.
D.
E.
325.
A.
B.
C.
D.
E. *
326.
A. *
B.
C.
D.
E.
327.
A.
B. *
C.
D.
E.
328.
Mouth
Nose
Skin
Vagina
Each of the statements about the classification of streptococci is correct EXCEPT:
Pneumococci {Streptococcus pneumoniae) are alpha-hemolytic and can be serotyped on the basis of
their polysaccharide capsules
Enterococci are group D streptococci and can be classified by their ability to grow in 6.5% sodium
chloride
Streptococci are classificate on basis on haemolytic properties
Although pneumococci and the viridans streptococci are alpha-hemolytic, they can be differentiated
by the bile solubility test and their susceptibility to optochin
Viridans streptococci are identified by Lancefield grouping, which is based on the C carbohydrate in
the cell wall
Each of the following agents is a recognized cause of diarrhea EXCEPT
Streptococcus epidermidis
Clostridium perfringens
Enterococcus faecalis
Escherichia coli
Vibrio cholerae
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?
Clostridium difficile
Streptococcus pyogenes
Shigella dysenteriae
Salmonella enteritidis
Shigella boydii
Each of the following statements concerning Mycobacterium tuberculosis is correct EXCEPT:
After being stained with carbolfuchsin, M. tuberculosis resists decolorization with acid alcohol
M. tuberculosis has a large amount of mycolic acid in its cell wall
M. tuberculosis appears as a violet rod in Gram-stained specimens
M. tuberculosis appears as a red rod in acid-fast stained specimens
M. tuberculosis appears as a blue rod in acid-fast stained specimens
Which one of the following diseases is BEST diagnosed by serologic means?
Q fever
Pulmonary tuberculosis
Gonorrhea
Actinomycosis
Sepsis
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?
Skin
Oropharynx
Colon
Mucose
Urethra
Corynebacterium diphtheriae produces exotoxin if:
A.
B. *
C.
D.
E.
329.
A. *
B.
C.
D.
E.
330.
A.
B.
C. *
D.
E.
331.
A.
B.
C. *
D.
E.
332.
A. *
B.
C.
D.
E.
333.
A.
B.
C.
D. *
E.
334.
A.
B.
Corynebacterium diphtheriae grows in Loeffler’s medium
Corynebacterium diphtheriae is lysogenic culture
Corynebacterium diphtheriae grows on tellurite agar
Corynebacterium diphtheriae is resistant to -lactame antibiotics
Corynebacterium diphtheriae has volutin granules.
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?
Streptococcus pyogenes
Staphylococcus aureus
Staphylococcus epidermidis
Streptococcus pneumoniae
Staphylococcus saprophyticus
The coagulase test, in which the bacteria cause plasma to clot, is used to distinguish
Streptococcus pyogenes from Enterococcus faecalis
Streptococcus pyogenes from Staphylococcus aureus
Staphylococcus aureus from Staphylococcus epidermidis
Staphylococcus epidermidis from Neisseria meningitidis
Neisseria gonorrhoae
The MOST important protective function of the antibody stimulated by tetanus immunization
is
To opsonize the pathogen (Clostridium tetani)
To prevent growth of the pathogen
To neutralize the toxin of the pathogen
To prevent adherence of the pathogen
To prevent inflammation of tissues
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?
Staphylococcus aureus
Clostridium perfringens
Enterotoxigenic Escherichia coli
Bacillus cereus
Salmonella typhi
For which one of the following enteric illnesses is a chronic carrier state MOST likely to
develop?
Campylobacter enterocolitis
Shigella enterocolitis
Cholera
Typhoid fever
Sepsis
Which one of the following zoonotic illnesses has NO arthropod vector?
Plague
Lyme disease
C. *
D.
E.
335.
A.
B. *
C.
D.
E.
336.
A.
B.
C.
D.
E. *
337.
A. *
B.
C.
D.
E.
338.
A.
B.
C.
D. *
E.
339.
A.
B. *
C.
D.
E.
340.
A.
B.
C.
D. *
E.
341.
A.
B.
C.
D.
Brucellosis
Epidemic typhus
Anthrax
Which one of the following organisms principally infects vascular endothelial cells?
Salmonella typhi
Rickettsia typhi
Haemophilus influenzae
Coxiella burnetii
Bordetella pertussis
A child has Pertussis. How was this infection most likely to have been acquired?
Release of oral flora into the bloodstream by dental work.
Bite of a dog or cat.
Contact with livestock, or animal products such as leather or wool.
Consumption of dairy products made from unpasteurized milk
Inhalation of respiratory droplets from another person.
A patient is diagnosed with Clostridium difficile colitis.
Which item would represent a known risk factor for such infections?
Been treated with antibiotics.
Consumed unpurified water.
Visited the southwestern United States.
Eaten undercooked fried rice.
Been in contact with livestock
Each of the following statements concerning chlamydiae is correct EXCEPT
Chlamydiae are strict intracellular parasites because they cannot synthesize sufficient ATP
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
Most chlamydiae are transmitted by arthropods
Chlamydiae aren‘t cultivated onto nutritient media
For which one of the following bacterial vaccines are toxic side effects an important concern?
The vaccine containing pneumococcal polysaccharide
The vaccine containing pneumococcal polysaccharide
The vaccine containing tetanus toxoid
The vaccine containing diphtheria toxoid
The vaccine containing botulinum toxoid
Each of the following statements concerning Staphylococcus aureus is correct EXCEPT
Gram-positive cocci in grapelike clusters are seen on Gram-stained smear
The coagulase test is positive
Treatment should include a (3-lactamase-resistant penicillin
Endotoxin is an important pathogenetic factor
It produce exotoxins
In the immune response to invasive infections by Streptococcus pneumoniae, antibodies are
required for effective defense. Antibodies to which antigen are most important?
Teichoic acid.
Type III secretion system.
Peptidoglycan.
C-carbohydrate.
E. *
342.
A. *
B.
C.
D.
E.
343.
A.
B. *
C.
D.
E.
344.
A.
B. *
C.
D.
E.
345.
A.
B.
C. *
D.
E.
346.
A.
B.
C. *
D.
E.
347.
A.
B.
C. *
D.
Polysaccharide capsule.
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?
Bacteroides fragilis and Klebsiella pneumoniae
Bordetella pertussis and Salmonella enteritidis
Actinomyces israelii and Campylobacter jejuni
Clostridium botulinum and Shigella dysenteriae
Salmonella typhimuruim and Shigella boydii
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 with
out evidence of swarming motility. Which one of the following organisms is MOST likely to be
the cause of his urinary tract infection?
Enterococcusfaecalis
Proteus vulgaris
Pseudomonas aeruginosa
Escherichia coli
Staphylococcus epidermidis
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
Treponema pallidum
Chlamydia trachomatis
Candida albicans
Coxiella burnetii
Neisseria gonorrheae
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?
Shigella flexneri
Helicobacter pylori
Campylobacter jejuni
Salmonella enteritidis
Vibrio cholerae
The MOST important contribution of the capsule of Streptococcus pneumoniae to virulence is
To prevent dehydration of the organisms on mucosal surfaces
To survive in the environment
To retard phagocytosis by polymorphonuclear leukocytes
To
inhibit polymorphonuclear leukocyte chemo taxis
To accelerate tissue invasion by its collage-naselike activity
The MOST important way the host circumvents the function of the pneumococcal
polysaccharide capsule is via
T lymphocytes sensitized to polysaccharide antigens
Polysaccharide-degrading enzymes
Anticapsular antibody
Activated macrophages
E.
348.
A.
B. *
C.
D.
E.
349.
A.
B.
C.
D. *
E.
350.
A. *
B.
C.
D.
E.
351.
A.
B.
C. *
D.
E.
352.
A.
B. *
C.
D.
E.
353.
A.
B.
C.
D. *
E.
354.
A.
B.
C.
Activated B-lymphocytes
The pathogenesis of which one of the following organisms is MOST likely to involve invasion of
the intestinal mucosa?
Vibrio cholerae
Shigella sonnei
Enterotoxigenic Escherichia coli
Clostridium botulinum
Salmonella typhi
Which one of the following organisms that in fects the gastrointestinal tract is the MOST frequent cause of bacteremia?
Shigella flexneri
Campylobacter jejuni
Vibrio cholerae
Salmonella typhi
Shigella sonnei
Each of the following statements concerning Treponema is correct EXCEPT:
T. pallidum produces an exotoxin that stimulates adenylate cyclase
Treponema are motile
T. pallidum cannot be grown on conventional laboratory media
Treponemes are members of the normal flora of the human oropharynx
Patients infected with T. pallidum produce antibodies that react with beef heart cardiolipin
Each of the following statements concerning Clostridia is correct EXCEPT:
Pathogenic Clostridia are found both in the soil and in the normal flora of the colon
Antibiotic-associated (pseudomembranous) colitis is due to a toxin produced by Clostridium difficile
Anaerobic conditions at the wound site are not required to cause tetanus, because spores will form in
the presence of oxygen
Botulism, which is caused by ingesting preformed toxin, can be prevented by boiling food prior to
eating
Clostridia are spore-forming bacteria
Each of the following statements concerning Bacteroides fragilis is correct EXCEPT:
B. fragilis is a gram-negative rod that is a part of the normal flora of the colon
B. fragilis forms endospores, which allow it to survive in the soil
The capsule of B. fragilis is an important virulence factor
B. fragilis infections are characterized by foul-smelling pus
B. fragilis is anaerobic bacterium
Each of the following statements concerning staphylococci is correct EXCEPT:
S. aureus is differentiated from S. epidermidis by the production of coagulase
S. aureus infections are often associated with abscess formation
The majority of clinical isolates of S. aureus elaborate penicillinase; therefore, presumptive antibiotic therapy for S. aureus infections should not consist of penicillin G
Scalded skin syndrome caused by S. aureus is due to enzymatic degradation of epidermal
desmosomes by catalase
Gram-positive cocci in grapelike clusters are seen on Gram-stained smear
Each of the following statements concerning gram-negative rods is correct EXCEPT:
E. coli ferments lactose, whereas the enteric pathogens Shigella and Salmonella do not
Salmonella typhi cause bactereamia
Klebsiella pneumoniae, although a cause of pneumonia, is part of the normal flora of the colon
D.
E. *
355.
A. *
B.
C.
D.
E.
356.
A.
B.
C.
D. *
E.
357.
A.
B.
C. *
D.
E.
358.
A.
B.
C. *
D.
E.
359.
A.
B. *
C.
D.
E.
360.
A.
B.
C.
D. *
E.
Proteus species are highly motile organisms that are found in the human colon and cause urinary
tract infections
Escherichia coli is part of the normal flora of the colon; therefore, it does not cause diarrhea
Which one of the following organisms causes diarrhea by producing an enterotoxin that
activates adenylate cyclase?
Escherichia coli
Bacteroides fragilis
Staphylococcus aureus
Enterococcus faecalis
Costridium difficilae
Each of the following statements concerning Clostridium perfringens is correct EXCEPT:
It causes gas gangrene
It causes food poisoning
It produces an exotoxin that degrades lecithin and causes necrosis and hemolysis
It is a gram-negative rod that does not ferment lactose
It causes experimental infection in animals
Each of the following statements concerning Clostridium tetani is correct EXCEPT:
It is a gram-positive, spore-forming rod
Pathogenesis is due to the production of an exotoxin that blocks inhibitory neurotransmitters
It is a facultative organism; it will grow on a blood agar plate in the presence of room air
Its natural habitat is primarily the soil
It is motile rod
Each of the following statements concerning spirochetes is correct EXCEPT:
Species of Treponema are part of the normal flora of the mouth
Species of Borrelia cause a tick-borne disease called relapsing fever
The species of Leptospira that cause leptospirosis grow primarily in humans and are usually
transmitted by human-to-human contact
Species of Treponema cause syphilis and yaws
Borrelia burgdorferi causes Lyma disease
Each of the following statements concerning Mycobacterium tuberculosis is correct EXCEPT:
Some strains isolated from individuals with previously untreated cases of tuberculosis are resistant to
isoniazid
M. tuberculosis contains a small amount of lipid in its cell wall and therefore stains poorly with the
Gram stain
The organism grows slowly, often requiring 3-6 weeks before colonies appear
The antigen in the skin test is a protein extracted from the organism
Mantoux test is used for allergic diagnosis
Which one of the following statements concerning immunization against diseases caused by
Clostridia is CORRECT?
Antitoxin against tetanus protects against botulism as well, because the two toxins share antigenic
sites
Vaccines containing alpha toxin (lecithinase) are effective in protecting against gas gangrene
The toxoid vaccine against Clostridium difficile infection should be administered to immunocompromised patients
Immunization with tetanus toxoid induces effective protection against tetanus toxin
Attenuated vaccines are used for specific prophylaxis of infections, caused by Clostridia
361.
A. *
B.
C.
D.
E.
362.
A.
B.
C. *
D.
E.
363.
A.
B.
C. *
D.
E.
364.
A.
B. *
C.
D.
E.
365.
A. *
B.
C.
D.
E.
366.
A.
B.
C. *
D.
When ampicillin was first introduced, most E. coli isolates were clinically sensitive. Many isolates
are now ampicillin-resistant because they produce β-lactamases. Which phrase below most accurately
describes these enzymes?
Genes which encode them are often present on conjugative plasmids
. Although they are produced by many isolates of E. coli, such β-lactamases are not produced by
other Gram-negative rods.
They inactivate all β-lactam antibiotics
They cause resistance to aminoglycosides as well as b-lactams
They have spread from Gram-negatives like E. coli to Gram-positive pathogens like
Staphylococcus aureus.
Many isolates of E. coli are now ampicillin-resistant because they produce β-lactamases. Which
sentence below most accurately describes these enzymes?
They inactivate all β-lactam antibiotics.
Although they are produced by many isolates of E. coli, such β-lactamases are not produced by other
Gram-negative rods.
Genes which encode them are often present on conjugative plasmids
They cause resistance to aminoglycosides as well as b-lactams.
They have spread from Gram-negatives like E. coli to Gram-positive pathogens like
Staphylococcus aureus.
A patient complains of abdominal pain and you suspect gastritis caused by Helicobacter pylori. Of
the tests below, which would it be best to order, to confirm your diagnosis?
Sputum culture.
Blood culture on special selective medium.
Conversion of 14C-labeled urea to carbon dioxide.
Measurement of urea concentration in exhaled breath.
Measurement of urea concentration in a stool sample.
A man suffers many month from gastritis caused by Helicobacter pylori . Of the tests below, which
would it be best to order, to confirm your diagnosis?
Measurement of urea concentration in a stool sample.
Conversion of 14C-labeled urea to carbon dioxide.
Blood culture on special selective medium.
Sputum culture.
Measurement of urea concentration in exhaled breath.
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?
Flagella and O-antigen.
. Peptidoglycan and teichoic acid.
Heat-labile and heat-stable enterotoxins.
Pili and capsular polysaccharide.
Hemolysin and cell-wall-associated carbohydrate
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?
Heat-labile and heat-stable enterotoxins.
Peptidoglycan and teichoic acid.
Flagella and O-antigen.
Pili and capsular polysaccharide.
E.
367.
A.
B.
C. *
D.
E.
368.
A.
B.
C. *
D.
E.
369.
A.
B. *
C.
D.
E.
370.
A.
B. *
C.
D.
E.
371.
A.
B.
C.
D.
E. *
372.
A.
B. *
C.
D.
E.
373.
Hemolysin and cell-wall-associated carbohydrate.
A patient with a bacterial infection is treated with a bacteriostatic inhibitor of 70S ribosomes.Which
drug below best fits this description?
Rifampin.
A fluoroquinolone.
Tetracycline.
An aminoglycoside.
Erythromycin.
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?
Clostridium difficile.
Clostridium botulinum
Clostridium perfringens.
Clostridium tetani.
Listeria monocytogenes
A bacillus cultured from stool produces dark pink colonies on Endo agar.
Which of the following organisms is most likely?
Shigella dysenteriae
Escherichia coli
Salmonella enterica
Listeria monocytogenes
Shigella sonnei
Which bacteria can produce on Endo’s medium dark pink colonies?
Salmonella enterica
Escherichia coli
Listeria monocytogenes
Shigella sonnei
Shigella dysenteriae
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?
Culture of urine on broth-based agar at 20ºC.
Culture of cervical exudate on chocolate agar in elevated CO2.
Microscopic examination of a stained smear of peripheral blood.
Gram stain of exudate from the cervix.
PCR-based nucleic-acid amplification test of a cervical swab.
An HIV-positive patient develops mycobacterial infection. Two likely possibilities are
Mycobacterium avium-intracellulare and Mycobacterium tuberculosis. How would these bacteria be
best distinguished in the laboratory?
One is Gram-positive, the other is acid-fast.
Nucleic acid from one hybridizes to a specific DNA probe, nucleic acid from the other does not.
One is a rod, the other is a coccus.
One grows on Jensen-Lowenstein agar, the other does not
One grows in the BACTEC system, the other does not.
A patient with upper respiratory disease is observed to have a thick grey ‘pseudomembrane’ lining
the upper respiratory tract. Which organism below is most likely in this case?
A.
B. *
C.
D.
E.
374.
A.
B.
C. *
D.
E.
375.
A.
B.
C.
D.
E. *
376.
A.
B.
C. *
D.
E.
377.
A.
B.
C.
D. *
E.
378.
A. *
B.
C.
D.
E.
379.
A.
B.
C. *
D.
E.
Mycobacterium tuberculosis
Corynebacterium diphtheriae
Legionella pneumophilia.
Pseudomonas aeruginosa
Nocardia asteroids
A listless child with extremely poor muscle tone is brought to the Hospital. Which condition is most
likely, given this presentation?
Lyme Disease
Tetanus
Botulism
Rocky Mountain spotted fever
Rheumatic fever
An epidemic typhus occurs in a refugee camp. What vectors spread the infections?
Rat fleas.
Dog ticks.
Deer ticks.
Mosquitos.
Human body lice.
What vectors are spread an epidemic typhus?
Rat fleas.
Dog ticks.
Human body lice.
Mosquitos.
Deer ticks.
A patient has a large carbuncles you suspect is caused by Bacillus anthracis. In this case, which of
the following would you expect to see in a Gram-stained smear of pus from the carbuncles?
Slender spirochetes.
Small Gram-positive cocci, in pairs.
Gram-negative rods of variable length.
Large Gram-positive rods.
Gram-negative coccobacilli.
A young man has urethritis. Titer of Complement-fixing (CF) antibody to Chlamydia trachomatis,
in a serum sample taken on the day on which treatment was initiated, is 1:64. A second CF titer,
taken two weeks later, is 1:640. Which conclusion below best follows from the antibody titers?
The patient’s urethritis was caused by C. trachomatis
Although the patient’s condition may appear to be improving, in fact his infection is getting worse.
The patient is not infected with C. trachomatis.
The patient has made a Type I hypersensitivity response to C. trachomatis antigens.
The patient’s C. trachomatis isolate was resistant to tetracyclines
Clostridium tetani produces disease by the production of a protein exotoxin.
How does this toxin act?
Stimulates adenyl cyclase.
Inhibits guanyl cyclase.
Blocks synaptic transmission.
Cleaves ribosomal RNA.
Stimulates production of cytokines.
380.
A.
B. *
C.
D.
E.
381.
A.
B.
C. *
D.
E.
382.
A.
B.
C. *
D.
E.
383.
A.
B.
C.
D. *
E.
384.
A.
B.
C. *
D.
E.
385.
A.
B.
C. *
D.
E.
You suspect that a patient’s respiratory illness may be due to infection by Mycoplasma pneumoniae.
If this is true, which antibiotic below should you expect to be most effective?
Penicillin G.
Erythromycin.
Vancomycin.
A third-generation cephalosporin.
An ‘extended-spectrum’ penicillin.
Which antibiotic below should you expect to be most effective for therapy Mycoplasma pneumoniae
respiratory infection?
. Penicillin G.
Vancomycin.
Erythromycin.
A third-generation cephalosporin.
An ‘extended-spectrum’ penicillin.
A young man complaines on pain on urination and profuse purulent discharge from his urethral
opening. 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?
Mycoplasma hominis
Chlamydia trachomatis
Neisseria gonorrhoeae
Ureaplasma urealyticum
Treponema pallidum
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?
Clostridium difficile Cytotoxin.
Escherichia coli Labile Toxin
Escherichia coli Stable Toxin.
Staphylococcus aureus Enterotoxin.
Helicobacteri pylori Cytotoxin.
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?
Rickettsia rickettsii
Treponema pallidum
. Borrelia burgdorferi
. Chlamydia psittaci
Streptococcus pyogenes
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?
Streptococcus pyogenes Erythrogenic toxin.
Clostridium perfringens α-toxin.
Staphylococcus aureus Toxic Shock Syndrome Toxin-1.
Shigella dysenteriae Shiga Toxin.
Escherichia coli Heat-labile Toxin (ST).
386.
A.
B. *
C.
D.
E.
387.
A.
B.
C. *
D.
E.
388.
A.
B.
C.
D. *
E.
389.
A.
B.
C.
D. *
E.
390.
A. *
B.
C.
D.
E.
391.
A.
B.
C. *
D.
E.
_____ The laboratory informs you that an isolate of Staphylococcus aureus is ‘methicillin-resistant’.
Which phrase below best describes such isolates?
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 β-lactams.
They produce a β-lactamase active on both cephalosporins and penicillins.
The ‘methicillin-resistance’ gene also confers resistance to vancomycin.
Gram stain of CSF sediment from a patient with meningitis contains Gram-negative cocci, many in
pairs. Which organism below is most probable?
Streptococcus pneumoniae
Haemophilus influenzae
Neisseria meningitidis
Pseudomonas aeruginosa
Escherichia coli
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?
Escherichia coli
Haemophilus influenzae
Listeria monocytogenes
Neisseria meningitidis
Streptococcus agalactiae
Group A b-hemolytic streptococci are cultured from a throat swab of a febrile child with severe
purulent pharyngitis. Structure of which antigen determined that the bacteria belonged to Lancefield
group A?
. Capsular polysaccharide
Side chains of peptidoglycan.
Fimbrae proteins
Cell-wall-associated with carbohydrate
Streptolysin O.
Structure of which antigen b-hemolytic streptococci determined that the bacteria belonged to
Lancefield group A?
Cell-wall-associated with carbohydrate.
Side chains of peptidoglycan.
Fimbrae proteins
Capsular polysaccharide.
Streptolysin O.
Residents of an assisted-living facility are offered immunization against Streptococcus pneumoniae.
What is the antigenic constituent of this vaccine?
Killed whole cells.
Live cells of an attenuated bacterium.
Purified capsular polysaccharides.
Proteins produced by genetic engineering.
A toxoid (formaldehyde-inactivated toxin).
392.
A.
B.
C. *
D.
E.
393.
A.
B.
C.
D.
E. *
394.
A.
B.
C. *
D.
E.
395.
A.
B. *
C.
D.
E.
396.
A.
B. *
C.
D.
E.
397.
A.
B.
C.
D.
E. *
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?
Shortens the course of the infection.
Prevents spread of the infection to adjacent sites.
Prevents sequellae such as acute rheumatic fever.
Stimulates development of protective immunity
Prevents spread of the infection to others.
A patient has endocarditis produced by an a-hemolytic Streptococcus. This usually reflects spread of
normal flora to the bloodstream. From which site is this isolate most likely to have spread?
Anterior nares.
Facial skin.
Lower respiratory tract.
Distal urethra.
Oropharynx.
From which site is L(alpha)-hemolytic Streptococcus isolate most likely to have spread in blood?
Facial skin.
Anterior nares.
Oropharynx.
Lower respiratory tract.
Distal urethra.
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?
Staphylococcus epidermidis
Streptococcus pneumoniae
Staphylococcus aureus
Streptococcus agalactiae
Streptococcus pyogenes
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?
Blackening of a bile-esculin slant.
Coagulation of citrate-treated plasma.
Beta-hemolysis on sheep blood agar.
Blackening of an oxidase-test disc placed on a colony.
Resistance to bacitracin.
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?
Mycoplasma hominis
Chlamydia trachomatis
Treponema pallidum
Ureaplasma urealyticum
Neisseria gonorrhoeae
398.
A.
B.
C.
D.
E. *
399.
A.
B.
C. *
D.
E.
400.
A.
B.
C. *
D.
E.
401.
A.
B.
C.
D. *
E.
402.
A.
B.
C.
D. *
E.
403.
A. *
B.
C.
D.
E.
In October a young man comes to your office with two ulcers on his right hand. His history includes
the fact that he is an avid hunter, and has been rabbit hunting in southern New Jersey every weekend
for the last several months. Which organism should his hobby cause you to add to the list of possible
causes of his illness?
Yersinia pestis.
Coxiella burnetii.
Listeria monocytogenes.
A member of the genus Brucella.
Francisella tularensis.
Bacteroides fragilis is isolated from an operative wound. Which sentence below best describes such
infection?
Can be successfully treated with aminoglycosides alone
Initiated by ingestion of spores.
Can be successfully treated with metronidazole alone.
Contracted by the respiratory route.
Sexually-transmitted.
A patient with urethritis is treated with tetracycline. A direct fluorescent antibody test of a smear of
exudate is equivocal. Titer of Complement-fixing (CF) antibody to Chlamydia trachomatis, in a
serum sample taken on the day on which treatment was initiated, is 1:32. A second CF titer, taken
two weeks later, is 1:640. Which conclusion below best follows from the antibody titers?
The patient is not infected with C. trachomatis.
Although the patient’s condition may appear to be improving, in fact his infection is getting worse.
The patient’s urethritis was caused by C. trachomatis.
The patient has made a Type I hypersensitivity response to C. trachomatis antigens.
The patient’s C. trachomatis isolate was resistant to tetracyclines
Residents of an assisted-living facility are immunized against Streptococcus pneumoniae. What
is the antigenic component of the vaccine?
A protein toxoid.
Killed whole bacteria.
Purified toxin.
Purified capsular polysaccharides.
Live bacteria of attenuated virulence
In the upper respiratory tract of patient doctor observed thick grey ‘pseudomembrane’ formation.
Which organism can cause this symptoms?
Mycobacterium tuberculosis
Legionella pneumophilia.
Streptococcus mitis
Corynebacterium diphtheriae
Pseudomonas aeruginosa
Staphylococcus aureus is easily transmitted within the hospital environment.
Which feature of this bacterium is most largely responsible for its ease of spread?
Resistance to heat, cold, and drying.
Ability to colonize the digestive tract.
Presence of an outer membrane impermeable to most disinfectants.
Production of extracellular polysaccharide which allows bacteria to
adhere tightly to surfaces.
Formation of spores which are resistant to disinfectants and easily dispersed.
404.
A.
B. *
C.
D.
E.
405.
A. *
B.
C.
D.
E.
406.
A. *
B.
C.
D.
E.
407.
A. *
B.
C.
D.
E.
408.
A. *
B.
C.
D.
E.
409.
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?
Capsule polysaccharide.
Cell-associated or C-carbohydrate.
Wall and membrane teichoic acids.
Beta-hemolysins.
Filamentous proteins of the cell envelope.
An important virulence factor of coagulase-positive staphylococci is Protein A.
How does Protein A aid in virulence?
Binds the Fc region of IgG, decreases opsonization.
Hydrolyzes secretory IgA.
Binds Factor H, prevents activation of complement.
Extracts iron from plasma proteins.
Promotes tight binding of bacteria to extracellular matrix.
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?
Staphylococcus aureus
Staphylococcus epidermidis
Streptococcus pyogenes (Group A)
Streptococcus agalactiae (Group B)
Streptococcus pneumoniae
A five-day-old child develops high fever and stiff neck. A spinal tap is performed. A Gram-stained
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?
Escherichia coli
Streptococcus pneumoniae
Streptococcus agalactiae
Haemophilus influenzae
Neisseria meningitidis
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 probable?
Neisseria meningitidis
Haemophilus influenzae
Streptococcus pneumoniae
Pseudomonas aeruginosa
Escherichia coli
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 golden-yellow. Catalase and coagulase tests were positive.
What was the most likely pathogen?
A. *
B.
C.
D.
E.
410.
A.
B. *
C.
D.
E.
411.
A.
B.
C.
D.
E. *
412.
A.
B.
C. *
D.
E.
413.
A.
B.
C.
D. *
E.
414.
A. *
B.
C.
Staphylococcus aureus
Staphylococcus epidermidis
Streptococcus pyogenes
Streptococcus pneumoniae
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?
Ability to invade cells.
Adhesive pili.
Anti-phagocytic capsule.
Endotoxin.
Flagella.
Heavily-encapsulated strains of Neisseria meningitidis are far more virulent than
non-encapsulated isolates. How does a capsule enhance virulence?
Binds to the Fc region of some subclasses of human IgG.
Prevents activation of complement by the classical pathway.
Enables bacteria to adhere tightly to mammalian cells.
Reduces access of antibiotics to the bacterial membrane.
Inhibits phagocytosis by neutrophils
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?
Urethral epithelium.
Gall bladder.
Nasopharynx.
Large intestine.
Meninges and choroid plexus.
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?
Gram-positive cocci, many in pairs.
Gram-positive cocci, many in clusters.
Isolated Gram-positive cocci.
Gram-negative cocci, many in pairs.
Gram-negative cocci, many in clusters.
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?
Lipopolysaccharide [LPS].
Teichoic acid.
A superantigen toxin.
D.
E.
415.
A.
B. *
C.
D.
E.
416.
A.
B. *
C.
D.
E.
417.
A.
B. *
C.
D.
E.
418.
A. *
B.
C.
D.
E.
419.
A.
B.
C. *
D.
E.
420.
A.
B.
C.
Capsular polysaccharide.
Plasma membrane lipids.
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?
Gram-positive.
Ferment lactose.
Not likely to be 'normal flora'.
Non-motile.
Produce capsules.
A strain of bacteria produced color colonies when cultured on standard MacConkey agar. It
was then used to inoculate a Kligler's Iron Agar (KIA). 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?
Produces H2S and gas
Ferments lactose and produces gas
Ferments neither lactose nor sucrose.
Ferments glucose only
Ferments sucrose and produces gas.
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?
Capsule.
Carbohydrate chains of LPS.
Flagella
Pili.
Teichoic acid.
A common serotype of enterohemorrhagic E. coli is O157:H7.
To which bacterial structure does the "H7" correspond?
Flagella.
Pili.
Capsule.
LPS core polysaccharide.
Porins.
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?
ADP-ribosylates a chloride transporter.
Inhibits a G protein that inhibits adenyl cyclase.
Stimulates a G protein that activates adenyl cyclase.
Stimulates guanyl cyclase.
Inhibits guanyl cyclase.
A vacationing couple both develop severe watery diarrhea which lasts three days.
Which organism is the most common etiologic agent of such infections?
Shigella sonnei.
Pseudomonas aeruginosa.
Salmonella typhi.
D.
E. *
421.
A.
B. *
C.
D.
E.
422.
A.
B.
C.
D. *
E.
423.
A.
B.
C.
D.
E. *
424.
A.
B. *
C.
D.
E.
425.
A.
B.
C.
D. *
E.
426.
A.
B.
Campylobacter jejuni.
Escherichia coli.
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 conjugative plasmid that contains antibiotic-resistance transposons.
A plasmid-borne gene which encodes a heat-stable peptide toxin that stimulates guanyl cyclase.
A pathogenicity island which enables E. coli to invade mammalian cells.
A toxin that cleaves ribosomal RNA's.
An iron-transport system more efficient than that present in non-pathogenic E. coli.
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?
Non-typhoidal Salmonella.
Helicobacter pylori.
Campylobacter jejuni.
Enterotoxigenic E. coli.
Non-cholera Vibrio.
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?
Salmonella enteritidis.
Pseudomonas aeruginosa.
Serratia marcescens.
Klebsiella pneumoniae.
Escherichia coli.
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 Gram-negative rod.In situations such as this, what is the most likely
Enterobacter
pathogen? faecium
Escherichia coli
Proteus vulgaris
Klebsiella pneumoniae
Pseudomonas aeruginosa
A young child develops bloody diarrhea, produced by Shigella infection.
From which source was this infection most likely to have been contracted?
Cow, horse, or sheep.
Rare hamburger.
Dog or cat.
Another sick child.
Spores present in soil.
A patient becomes infected with Salmonella enterica serotype typhi. Which condition would
most strongly favor development of a "chronic carrier state" with this organism?
Age over 70 years.
Infection via the respiratory route.
C. *
D.
E.
427.
A.
B. *
C.
D.
E.
428.
A.
B. *
C.
D.
E.
429.
A. *
B.
C.
D.
E.
430.
A.
B.
C.
D. *
E.
431.
A.
B.
C.
D.
E. *
432.
A. *
B.
C.
Presence of gallstones.
Presence of kidney stones.
Chronic pulmonary disease.
Which phrase best describes typical infections by Campylobacter jejuni?
Non-inflammatory enteritis
Inflammatory enteritis
Systemic infection
Urinary tract infection
Meningitis
A patient has chronic gastritis. Which of the following organisms is most likely?
A non-cholera Vibrio.
Helicobacter pylori.
Campylobacter fetus.
Campylobacter jejuni.
Escherichia coli.
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?
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
A patient with systemic febrile illness is found to have an infection with Brucella abortus.
Which item in his history represents a known risk factor for such infections?
Recently visited Grand Canyon National Park.
Keeps numerous pet reptiles including two pythons and an alligator.
Has two young children who attend day care.
Works as a butcher for a supermarket chain.
Has an acquarium at home, with numerous tropical fish.
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, Gram-positive 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?
Pseudomonas aeruginosa.
Proteus mirabilis.
Klebsiella pneumoniae
Prevotella melaninogenica.
Bacteroides fragilis.
In Europe human Tetanus is now a rare disease. Which measure below has been most important in
preventing it?
Immunization of humans with a toxoid-containing vaccine.
Eradication of the organism from the environment.
Vaccination of livestock, especially cattle, with a killed-organism vaccine
D.
E.
433.
A.
B.
C.
D.
E. *
434.
A.
B.
C. *
D.
E.
435.
A.
B.
C.
D.
E. *
436.
A.
B.
C. *
D.
E.
437.
A.
B. *
C.
D.
E.
438.
A.
B. *
C.
Sewage treatment and purification of water supplies.
Antibiotic treatment of contacts of patients with C. tetani infections.
Why tetanus is now a rare disease. Which factors below has been most important in preventing it?
Eradication of the organism from the environment.
Sewage treatment and purification of water supplies.
v
Vaccination of livestock, especially cattle, with a killed-organism vaccine
Antibiotic treatment of contacts of patients with C. tetani infections.
Immunization of humans with a toxoid-containing vaccine.
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
Gram-positive rods. Which organism below is most likely to have caused this infection?
Clostridium botulinum.
Clostridium difficile.
Clostridium perfringens.
Clostridium tetani.
Listeria monocytogenes
How we can distinguish S. aureus from staphylococci epidermidis?
Colony color when grown on BHI agar.
Production of catalase.
Ability to grow on MacConkey agar.
Type of hemolysis on sheep blood agar.
Production of coagulase.
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?
The majority is...
Staphylococcus aureus Penicillin G
. Enterobacteriaceae Penicillin G
Mycobacterium tuberculosis Isoniazid
Obligate anaerobes Aminoglycosides
Obligate aerobes Metronidazole
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?
Rickettsia rickettsii
Borrelia burgdorferi
Treponema pallidum
Chlamydia psittaci
Streptococcus pyogenes
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?
Helicobacteri pylori Cytotoxin.
. Staphylococcus aureus Enterotoxin.
Escherichia coli Labile Toxin
D.
E.
439.
A.
B. *
C.
D.
E.
444.
Escherichia coli Stable Toxin.
Clostridium difficile Cytotoxin.
A febrile patient with E. coli sepsis develops ‘septic shock’.
Which of the following is likely to have played largest role in this reaction?
A humoral immune response to bacterial surface antigens.
A cell-mediated immune response to bacteria.
Secretion of cytokines by monocytes in response to stimulation by LPS [endotoxin].
Release of granule contents by mast cells and basophils.
Secretion of a bacterial superantigen toxin that activates TH cells.
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 appropriate?
. Shigella sonnei
Salmonella typhi
Pseudomonas aeruginosa
Escherichia coli
Klebsiella pneumoniae
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?
Copper
Potassium
Sodium
Magnesium
Iron
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?
Haemophilus influenzae
Staphylococcus aureus
Streptococcus pneumoniae
Neisseria gonorrhoeae
Nocardia asteroides
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?
Haemophilus influenzae
Neisseria gonorrhoeae
Streptococcus pneumoniae
Staphylococcus aureus
Nocardia asteroides
You suspect that a patient might have latent Syphilis. Which test below would most reliably detect it?
A.
B.
C. *
D.
Physical exam to detect characteristic neurological symptoms
Dark field microscopy of CSF.
Tests for ‘non-treponemal’ and ‘anti-treponemal’ antibodies in serum.
Culture of the organism from blood and CSF.
A.
B.
C. *
D.
E.
440.
A.
B.
C. *
D.
E.
441.
A.
B.
C.
D.
E. *
442.
A.
B.
C.
D. *
E.
443.
E.
445.
A. *
B.
C.
D.
E.
446.
A.
B. *
C.
D.
E.
447.
A. *
B.
C.
D.
E.
448.
A.
B.
C. *
D.
E.
449.
A.
B.
C.
D. *
E.
450.
A.
B.
C.
D.
Gram stain of material from a skin lesion.
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
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?
Staphylococcus aureus
Streptococcus bovis
Streptococcus pneumoniae
Streptococcus mitis
Enterococcus faecalis
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?
Enterococcus faecalis
Staphilococcus aureus
Streptococcus bovis
Streptococcus pneumoniae
Streptococcus mitis
A cyanotic, listless, infant with extremely poor muscle tone is brought to the Emergency Room.
Which condition is most likely, given this presentation?
Botulism
Tetanus
Lyme Disease
Rocky Mountain spotted fever
Rheumatic fever
A patient has a skin ulcer you suspect is caused by Bacillus anthracis. If your hypothesis is true,
which of the following would you expect to see in a Gram-stained smear of exudate from the wound?
Slender spirochetes.
Small Gram-positive cocci, in pairs.
Large Gram-positive rods.
Gram-negative rods of variable length.
Gram-negative coccobacilli.
Bordetella pertussis is:
Gram "+"
Modified acid fast "+"
Acid fast "+"
Gram "-"
Urease "+"
Which disease is caused by Streptococcus pneumoniae?
Nasopharyngeal carcinoma
Toxic shock syndrome
Reiter's syndrome
Scrub typhus
E. *
451.
A.
B.
C. *
D.
E.
452.
A. *
B.
C.
D.
E.
453.
A.
B.
C. *
D.
E.
454.
A.
B.
C.
D. *
E.
455.
A.
B.
C. *
D.
E.
456.
A. *
B.
C.
D.
E.
457.
A.
B.
C. *
D.
E.
Pneumonia
Phenotypic properties of Streptococcus pyogenes is:
Urease "+"
dsDNA
Catalase "-"
H2S "-"
Coagulase "-"
Which of the following are true according to Streptococcus agalactiae
A.
Normal vaginal flora
A.
Botulism symptoms include descending paralysis, dry mouth, constipation, and urinary
retention.
A.
Yeast form - in tissues; hyphae and pseudohyphae - both in tissues and in nature
(temperature/nutrition dependent)
A.
Exposure to antibiotics - major risk factor.
N. asteroides & N. caviae - pulmonary infections; N. brasiliensis - skin infections. Rare in
immunocompetent.
Neisseria gonorrhoeae
Fungi
Helminths
Bacteria
Viruses
Protozoa
Oxygen requirements of Staphylococcus epidermidis is:
Aerobic
Obligate anaerobe
Microaerophilic
Facultative anaerobe
Capnophilic
Staphylococcus epidermidis is:
Aerobic
Obligate anaerobe
Facultative anaerobe
Microaerophilic
Obligate aerobic
Which of the following statements refers to Coxiella burnetii :
May include pneumonia, hepatitis, and endocarditis.
Masseter muscles are often the first to be affected producing trismus (lockjaw).
Strains A-C: trachoma. Strains D-K: genital infections. Strains L1-L3: lymphogranuloma venereum.
Receptor - CD21 (complement receptor type 2)
Disease is mostly caused by O1 Classic and El Tor strains; recently also O139
What is correct about Coxiella burnetii
Masseter muscles are often the first to be affected producing trismus (lockjaw)
Can cause diplopia,disphagia, disphonia
May include pneumonia, hepatitis, and endocarditis
Disease is mostly caused by O1 Classic and El Tor strains; recently also O139
Can be transmitted by the bites of foxes
458.
A.
B.
C.
D. *
E.
459.
A.
B.
C.
D. *
E.
460.
A.
B.
C. *
D.
E.
461.
A.
B.
C. *
D.
E.
462.
A.
B.
C.
D.
E. *
463.
A.
B.
C. *
D.
E.
464.
A.
B.
C. *
D.
E.
465.
A.
Morbidity of Pseudomonas aeruginosa is:
Lymphogranuloma venereum
Enteric fever
Necrotising faciitis
Sepsis
Subacute sclerosing panencephalitis
What disease can cause Salmonella typhi?
Lymphogranuloma venereum
Sepsis
Necrotising faciitis
Enteric fever
Subacute sclerosing panencephalitis
Helicobacter pylori is:
Vibrio
Mold
Spiral-shaped
Rod
Yeast
Therapy of Candida albicans is:
Antitoxin
Cefotetan
Nystatin
Ketoconazole
Penicillin
What medicine is use for therapy of Candida albicans infection
Penicillin
Ketoconazole
Antitoxin
Cefotetan
Nystatin
Morbidity of Clostridium tetani is:
Cholera gravis
Pelvic inflammatory disease
Tetanus
Wound infection
Parotitis
Clostridium perfringens is сausative agent of:
Cholera gravis
Pelvic inflammatory disease
Wound infection
Parotitis
Tetanus
Which of the following statements refers to Clostridium botulinum
Includes S. typhimurium, S. dublin, S. enteritidis, S. hadar - enteritis; S. typhi, S. paratyphi - enteric
fever, possible intracellular infection.
B.
C.
D.
E. *
466.
A.
B.
C. *
D.
E.
467.
A.
B. *
C.
D.
E.
468.
A.
B. *
C.
D.
E.
469.
A.
B.
C. *
D.
E.
470.
A.
B.
C.
D. *
E.
471.
A. *
B.
C.
D.
E.
472.
A.
B.
Group is determined base on polysaccharide C; type - based on M-protein; strain - based on T
antigen.
Toxins: Stx - EHEC; ShET2 - EIEC.
Exposure to antibiotics - major risk factor
Botulism symptoms include descending paralysis, dry mouth, constipation, and urinary retention.
Find the correct sentence according to Clostridium botulinum
Includes S. typhimurium, S. dublin, S. enteritidis, S. hadar - enteritis; S. typhi, S. paratyphi - enteric
fever, possible intracellular infection.
Group is determined base on polysaccharide C; type - based on M-protein; strain - based on T
antigen.
Botulism symptoms include descending paralysis, dry mouth, constipation, and urinary retention
Exposure to antibiotics - major risk factor.
.
Produce endotoxin and coagulase.
Phenotypic characteristic of Chlamydia pneumoniae is:
ssDNA
Obligate intracellular parasite
ssRNA
Coagulase "+"
streptobacillus
Chlamydia pneumoniae is:
ssDNA
Obligate intracellular parasite
It grows onto nutrient media
Coagulase "+"
Acid fast "+"
Toxicogenity of Vibrio cholerae is accociated with:
LPS
Toxic shock syndrome toxin
Toxin - activates adenylate cyclase
Enterotoxins
Hemolysins
Phenotypic characteristic of Staphylococcus epidermidis is:
Optochin sensitive
Non-enveloped
Motility "+"
Coagulase "-"
Oxidase "+"
One of the phenotypic characteristic of Staphylococcus epidermidis is:
Coagulase "-"
Optochin sensitive
Non-enveloped
Oxidase "+"
Motility "+"
Normal microflora of water?
Staphylococcus aureus
E.coli
C. *
D.
E.
473.
A.
B.
C. *
D.
E.
474.
A.
B.
C.
D.
E. *
475.
A.
B.
C.
D. *
E.
476.
A.
B.
C.
D. *
E.
477.
A. *
B.
C.
D.
E.
478.
A. *
B.
C.
D.
E.
479.
A.
B.
C.
D. *
E.
480.
Micrococcus roseus
Salmonella typhy
Bacillus subtilis
Morphology of Yersinia enterocolitica is:
Mold
Cocci in chains
Rod
Cocci in clusters
Branching beaded rods
Morphology of Pneumococcus is:
Rod
Cocci in chains
Cyst
Spiral-shaped
Diplococci
Morbidity of Treponema pallium is:
Meningitis
Enteritis
Hepatitis
Syphilis
Food poisoning
Morbidity of Escherichia coli is:
Myocarditis
Fe deficiency anemia
Carbuncles
Sepsis
Pharyngitis
Group of Rickettsia prowazekii is:
Bacteria
Protozoa
Helminths
Fungi
Viruses
Group of Klebsiella spp is:
Bacteria
Helminths
Protozoa
Fungi
Viruses
Stain of Shigella spp. is:
Gram "+"
Modified acid fast "+"
Acid fast "+"
Gram "-"
Hinse
Group of Clostridium botulinum is:
A. *
B.
C.
D.
E.
481.
A.
B.
C.
D. *
E.
482.
A.
B.
C.
D.
E. *
483.
A.
B.
C.
D.
E. *
484.
A.
B.
C.
D. *
E.
485.
A.
B.
C.
D. *
E.
486.
A.
B.
C.
D.
E. *
487.
A.
B.
C. *
Bacteria
Protozoa
Fungi
Helminths
Viruses
Which of the following statements refers to Rickettsia rickettsii
Normal flora of the oral cavity
DNA homology studies indicate that only a single Brucella species, Brucella melitensis, is justified,
but the names Brucella abortus and Brucella suis (now considered biovars) are still in use.
Envelope consists of HBsAg
Pathogenesis - vasculitis
Toxin can be chronically produced in infant's colon causing infant botulism.
What is true according to Rickettsia rickettsii
Normal flora of the oral cavity
DNA homology studies indicate that only a single Brucella species, Brucella melitensis, is justified
Toxin can be chronically produced in infant's colon causing infant botulism.
Envelope consists of HBsAg
Pathogenesis - vasculitis
Morbidity of Candida albicans is
Endocarditis
Pneumonia
Bronchopneumonia
Bladder carcinoma
Systemic candidiasis
Morbidity of Klebsiella spp. is:
Rhinocerebral disease
Hemorrhagic cystitis
Enteritis
Urinary tract infections
Cervicitis
Group of Bordetella pertussis is:
Protozoa
Viruses
Fungi
Bacteria
Helminths
Phenotypic characteristic of Staphylococcus aureus is:
Enveloped
Motility "+"
ssRNAOxidase "-"
Coagulase "+"
Toxin of Chlamydia psittaci is:
Cholera toxin - activates adenylate cyclase
Exotoxin A - inhibits protein synthesis
LPS
D.
E.
488.
A.
B.
C.
D. *
E.
Elastase - hemorrage
Hemolysin
Mode of transmission of Herpes simplex virus is:
Mosquito bites
Perinatal
Droplet nuclei
Direct contact
Sexual