Download I. A bacterial population increases from 100 to I00,000,000 in 10

I. A bacterial population increases from 100 to I00,000,000 in 10 hours. What is the
generation time ofthis culture?
a. 30 minutes
b. 45 minutes
c. 60 minutes
d.2 hours
e. Not enough infonnation to detennine the generation time
2. What is the energy source for peptidoglycan crosslinking (transpeptidation)
a. Pentapeptide D-Ala-D-Ala last peptide bond
b. Pentaglycine bridge last peptide bond
c. ATP
d. NAM··UTP bond
e. C55 pyrophosphate bond
3. Fluoroquinolones affect
a. Protein synthesis by binding to the 23S ribosomal RNA
b. Protein synthesis by inhibiting tRNA binding to the ribosome
c. DNA replication by inhibiting DNA gyrase
d. DNA replication by inhibiting DNA polymerase
e. RNA synthesis by inhibiting RNA polymerase
f. RNA synthesis by inducing repressor binding
4. Which sequence is most commonly used for phylogenetic classification of bacteria
a. 238 ribosomal RNA
b. ]65 ribosomal RNA
c. RNA polymerase bela subunit
d. GroEL chaperone
e. Any conserved sequence
5. Which of the following best explains why the production of ethanol is important in
microbial cells that are under anaerobic conditions?
a. Ethanol keeps the electron transport system functioning
b. The organism would be lUlable to activate the enzymes of the Kliebs cycle without
ethanol
c. The process generates oxygen, which is required for glycolysis
d. The process regenerates NAD+, which is required for glycolysis
e. Ethanol stimulates rnitochondlial activity
6. Addition of salt to a culture medium only allows the salt-tolerant bacteria to grow.
This is an example ofa
a. Complex media
b. ChemicaJly defined media
c. Enrichment media
d. Differential media
e. Selective media
? Quorum sensing can involve
a. a secreted acyl bomoserine lactone
b. a secreted peptide
c. a two-component signaling system
d. regulation of biofi 1m formation
e. regulation of competence
f. all of the above
8. Two-component signaling systems typically involve
a. phosphorylation of histidine residues
b. methylation of aspartate residues
c. phosphorylation ofserine and threonine residues
d. enhanced DNA replication
e. sensing of intracellular metabolites
f. all of the above
9. Daptomycin
a. Is specific to Gram - bacteria
b. Causes Ca++ release from the cells in the presence of other ions
c. Causes release of other ions fiom the cells in the presence of Ca++
d. Inhibits protein synthesis by binding to the large ribosomal subunit
e. Inhibits RNA s)'llthesis by binding RNA polymerase
10. Erythromycin resistance is regulated at the level of
a. Transcription
b. Translation
c. Protein stability
d. Protein activity
e. Erythromycin resistance is not regulated
11. Which peptidoglycan precursor accwnulates in the presence of fosfomycin?
a. L-alanine
b. N-acetylgJucosarnine (NAG)
c. N-acety1muramic acid (NAM)
d. UDP-N-acetylmurarnic acid-L-ala-D-glu-L-Iys··
e. UDP-N-acetylglucosamine CUOP-NAG)
12. Asymptomatic carriage is:
a. Establishment ofa non disease-causing organism in the body
b. EstablisJunent of a disease-causing organism in the body
c. Infection in the absence of disease
d. Infection via a non-traditional portal of entry
e. Infection by a non-virulent pathogen
13. Characteristics used for bacterial identification include:
a. Differential (e.g. Gram) staining.
b. Biochemical testing.
c. rRNA sequencing.
d. In general, characteristics which evolve slowly.
e. In general, characteristics which arc casily testable.
f. a+b+e
g. a+b+c+d
h.a+c+d
i. b+c+e
14. Jf the bacterial mutation rate per generation is 10-7, this means that at each generation,
a. onc in 107 bacteria wilt have acquired a new point mutation
b. the chance that any give gene will have acquired a mutation is 10·7
c. about one in ten bacteria wiJl have acquired a new mutation
d. one in 107 daughter cells MIl have acquired a new point mutation
e. the number ofnew mutations cannot be estimated, since some oftbem will be
reverSJons
15. Movement of Listeria monocytogenes in the host cell cytoplasm is achieved by:
a. Sliding along the cellular membrane.
b. Using the bacterial flagella as a propeller.
c. Myosin polymerization.
d. Actin polymerization.
e. Forcing the phagolysosorne to move along cytoskeletal tracks.
16. The mechanism by which certain bacteria are able 10 inject proteins into host cells
is known as a
a. Type III secretion system
b. Hin injectase
c. IpaA injectase
d. Ton system
e. Two-component signaling system
17. Defensins are
a. Antibiotics
b. Bacterial endotoxins
c. Bacterial exotoxins
d. Antibacterial peptides
c. Iron chclators
18. Unbroken skin is:
a. Impenneable to all microorganisms.
b. Penneable to small bacteria.
c. Impenneable to bacteria.
d. Impermeable to bacteria, but provides a suitable environment for growth.
e. Penneablc to small bacteria, but bacterial growth is inhibited.
19. Bacterial virulence factors do Jiot include:
a. Exotoxins.
b. Pili.
c. LPS.
d. Glycolytic enzymes.
e. Siderophores.
L Capsules
20. Which statement regarding the Diphtheria toxin is incorrect
a. Is expressed only in high iron concentration.
b. Is the principal virulence factor of Corynebacterium diphtheriae.
c. Is an A-B toxin.
d. Is prophage-encoded.
e. Is regulated by dtxR.
f ADP-ribosylates translation elongation factor EF-2
21. Bacterial patllogenicity can often be understood as
a. The optimal way for the bacteria to thrive in the human body
b. Loss of optimal adaptation by a normally commensal organism
c. The normal mechanism by which the bacteria use a host as food source
d. A breakdown of host defense mechanisms
e. An lmavoidable byproduct ofany host-parasite interaction
22. In bacterial conjugation,
a. two bactcria from the same species mate, and generate recombinant progeny
b. two bacteria from different species mate, and generate hybrid progeny
c. the F factor is transmitted from the donor cell, which becomes F-, to the recipient
cell, which becomes F+
d. the F factor is transmitted from the donor cell, which remains F-I, to the recipient
cell, which becomes F+
e. the F factor is mobilized on a transposon that moves from a plasmid to the bacterial
chromosome or vice-versa
23. A recently hired laboratory technologist forgot the heat step (fixation) while
perfonning a Gram stain on Staphylococcus. ll1e most likely result is that the
organism would
a. Appear blue-violet.
b. Appear pink.
c. Be colorless.
d. Wash off the slide.
e. lyse.
24. Selective inhibition of synthesis of dipicolinic acid would most likely inhibit
fonnation of
a.
Bacterial flagella.
b.
eukaryotic flagella.
c.
Bacterial spores.
d.
fimbriae.
e.
mesosomes.
25. One hundred million bacteria/ml (1 x l08/mt) were counted while the viability
counts were perfonned on nutrient agar. The same nwnber was found when the
counts were pertonned on MacConkey, but some of the colonies were pink and
some were off-white. This result suggests that
a.
in the original test tube there was a mixture of two gram-negative
bacteria, one lactose-positive and the other laclose-negative.
b.
A mixture of gram-positive and gram-negative bacteria was in the test
tube.
c.
A genetic mutation changed the color of the colonies.
d.
An outside contamination of gram-positives occurred.
e.
b+ C
26. What is true concerning pili (fimbriae) in bacteria?
a.
They are present only in pathogenic bacteria.
b.
They can serve as virulence factor.
c.
Their connection to the substrate is dependent only on the electrical
charge.
d.
Their appearance is genetically dependent.
e.
They can serve as virulence factor and their appearance is genetically
dependent.
27. Which ofthe fo 1I0wing statements eoneeming the cell wall is not correct?
a.
The peptidoglycan layer is beneath the outer membrane in gram·
negative bacteria.
b.
The peptidoglycan layer is composed ofN-acetylglucosamine and Nacetylmuramic acid.
c.
The peptidoglycan layer is thicker in gram-negatives than in grampositive.
d.
The peptidoglycan layer is thicker in gram-positives than in gram-
negatives.
e.
All of the above is not correct.
28. Endospores of Bacillus subtilis are characterized by aJ] of the following except
a. Lack of metabolic activity.
b. Greater resistance than the vegetative cell to drying.
c. Multiple covering layers, including a peptidoglycan-containing sporewall cortex.
d. High calciwn content.
e. Lack of dipicolinic acid.
29. Sputum ofa patient suffering from pneumonia was scnt to the laboratory.
Diplococci were isolated. Which of the following statements is most
accurate?
a.
Diplococci are found only in the pharynx ofsick people.
b.
The causative agent is probably pneumococci.
c.
Diplococci are not found in the pharynx of healthy people.
d.
The pneumococci are definitely not the causative agent.
e.
Diplococci are not found in the pharynx of healthy people and they are
definitely not the causative agent.
30. All of the following statements concerning rheumatic fever are true except:
a. It is a complication of group A streptococcal pharyngitis.
b. It is a complication of group B streptococcal pharyngitis.
c. The pathogenesis is related to the similarity between streptococcal
antigen and a human cardiac antigen.
d. It is characterized by inflanunatory lesions that may involve joints and
the heart.
e. Prophylaxis can be provided by penicillin.
31. Cytoplasmic membranes of both gram-positive and gram-negative bacteria are
composed ofcomplex macromolecules. Which of the following statements
describes both gram"positive and gram-negative membranes?
a.
They are a diffusion barrier to large molecules.
b.
They act as a barrier to the extraction of crystal violet-Lugol complex by
alcohol.
c.
Their antigenic specificity is detennined by polysaccharide 0 antigen.
d.
They contain a significant amount ofteichoic acids.
e.
b+c
32. Pseudomembranous enterocolitis is effectively treated by
a.
cephalosporin.
b.
gentamicin.
c.
d.
penicillin.
vancomycm.
e.
Clindamycin
33.
A box ofsand\Viches with mayonnaise, prepared by a person with a boil on his
neck, was left on the table for 4 hours. All the people who ate those
sandwiches became ilL The most likely cause is
a.
Staphylococcus aureus enterotoxin.
b.
coagulase from StaphyLococcus aureus in the sandwiches.
c.
Staphylococcus aureus leukocidin.
d.
Clostridium welchii toxin.
e.
penicillinase.
34. A 21-year-old woman reported to the college infirmary complaining of frequency
of mination accompanied by a burning sensation, along with lower back pain.
A urine sample was sent to the laboratory and plated on MacConkey agar and
a blood-agar base (DAB). The following day, 3x IOs/ml gram-positive cocci
were found on BAB, but none were found on MacConkey.
likely causative agent?
a. Staphylococcus aureus
b. Staph. saprophyticus
c. Staph. epidermidis
d. Group B streptococci
e. Pneumococci
f. Staphylococcus aureus and Group B streptococci
Which is the most
35.
A patient who was brought to the hospital is suspected of gas gangrene
(myonecrosis). Cl welchii was isolated from the wound. Which of the
following statements is/are correct?
a. CI. welchii' is suspected to be the causative agent.
b. Only toxigenic Cl. welchii can cause this disease.
c. Antibiotic therapy is very important for treatment.
d. Lecithinase is one of the most important exotoxins in developing gas
gangrene.
e. All of the above
36. In South America an epidemic of cholera is confirmed.
applied because the antibiotics
a. Will directly lower the excretion ofliquid.
b. Will inhibit mUltiplication of the causative agent.
c. Will stop the activated toxin.
d. Will stop the activity ofadenyl cyclase.
c. None of the above
A regime of antibiotics is
37. In which ofthe following diseases is a chronic canier state most probable?
a. Shigellosis
b. Salmonellosis
c. Typhoid
d. Cholera
e. Typhus
38. a-Hemolysis is obtained on a blood-agar base medium.
bacteria is/are able to form a-hemolysis?
a. SIr. viridans
b. Sfr. pyogenes
c. Diplococcus pneurnoniae
d. SIr. Viridans and Diplococcus pneumoniae
e. Sfr. Viridans and Sfr. pyogenes
39. A patient was hospitalized, suspected ofhaving tetanus.
treatment you have 10 consider?
a.
Toxoid
b.
Antibiotics
c.
Antitoxin
d.
Infusion with saline and electrolytes
e.
Blood infusion
Which of the following
Which is the most urgent
40. A midstream sample of urine was sent to the laboratory. The wine was
quantitatively iuoculated after 6 hours at room te!TIQ.:., and the total number of
bacteria was found to be 4 x 105/m!. This result indicates that
a.
'Ibis person surely suffers from a severe urinary tract infection.
b.
An additional sample of urine should be sent to the laboratory to
coniirm the previous results.
c.
It might be an extemal contamination.
d.
b+C
e.
All ofthe above
41. A 25-year-old patient is admitted to the hospital because of diarrhea, with
erythrocytes and mucus in the stool. Two days earlier he ate hamburger. The
most likely causative microorganism is
a.
E. coli 0157:H7.
b.
Salmonella typhi.
c.
Vibrio cholera.
d.
Shigella sonnei.
e.
Helicobacter pylori.
42. Respiratory anthrax occurs following inhalation of spores. Which ofthe follm:ving
answers is correct?
a.
Edema factor, protective Ag and lethal factor are 3 proteins which
together act a~ a potent exotoxin.
b.
Rapid identification and antibiotic treatment are critical for preventing
high mortality rate.
c.
d.
e.
The spores are rapidly destroyed in the soil.
Direct person-ta-person spread of anthrax is very couunon.
The route ofcontamination is from the lesions ofthe skin to the lungs.
f.
arb are correct
g.
b +C are correct
h.
All the above is correct
43
.An effective vaccine exists to prevent infections from:
a.
Strep.pnewnonia (pneumococci)
b.
Strep. pyogenes
c.
Staph. aureus
d.
Neisseria gonorrhocae
e.
None of the above
44. Erythrogenic toxins derived from streptococci are thought to be involved in which
disease(s)
a.
scarlet fever
b.
sore throat
c.
STSS (Streptococcal Toxic Shock Syndrome)
d.
e.
Erysipelas
scarlet fever and STSS (Streptococcal Toxic Shock Syndrome)
f.
STSS (Streptococcal Toxic Shock Syndrome) and Erysipelas
45. When bacteria cause disease without spreading t.hrough host tissue, what is
the most common mechanism of damage?
a. secretion of toxins
b. production ofpili
c. production of capsule
d. intracellular cytotoxicity
e. None of the above~ bacteria must always spread tluough tissue to be a
successful pathogen.
46. Which ofthe following would not be identifiable by gram stain.
a. Staph. aureus
b. StT. pneurnoruae
c. E. coli
d. Bacillus
e. All ofthe above could be identified by gram stain.
47. Finding a catalase (-), IX hemolytic gram (+) coccus that is optochin
sensitive in a sputum sample that contains many ephithelial cells and a
severe cough means:
a. The person has influenza
b. The person has pneumonia
c. The person has whooping cough.
d. The person has a chronic bronchitis.
e. None of the above.
48. An epidemic of staphylococcal infections has appeared in the leU. In
attempt to find out who is the carrier ofthis particular strain you will
sample the hospital personal from:
a. Nasopharynx
b. Blood
c. Feces
d. Skin
e. Sputum
49. The most effective treatment for a case ofclinical tetanus would be:
a. Penicillin
b. Penicillin plus tetanus toxoid
c. Pcnicillin plus tetanus antitoxin
d. Polymyxin
e. None of the above- tetanus cannot be cured.
50. Why are patients with diarrhea caused by ETEC generally treated with
antibiotics?
a. To prevent the entry of these bacteria into the United States.
b. The disease can progress to urinary tract infections ifnot treated.
c. To help the patients enjoy their vacation.
d. To prevent further multiplication ofthe bacteria.
e. None of the above.
51. Helicobacter pylori is associated with all of the following except:
a. Gastritis
b. Peptic ulcer
c. Adenocarcinoma
d. Asymptomatic carriage.
e. Dysentery
51.. A patient who developed signs of endotoxemia was hospitalized. Which
statement is correct?
a.
Bacterial endotoxins are delivered only after lysis of gram negative
bacteria.
b.
The antigenic structure is due to lipid A.
c.
Bacterial endotoxlns are present in both gram (+) and gram (-)
bacteria.
d.
Toxoids can prevent endotoxernia.
e.
Antitoxins against endotoxin are available
53. All the following diseases develop due to exotoxin activation except
a. cholera.
b. acute gastroenteritis (E. coli).
c. tetanus.
d. Glomerulonephritis
e. botulism.
51\-. In South America an epidemic ofcholera is confirmed. A regime ofantibiotics is
applied because the antibiotics
a.
Will directly lower the excretion ofliquld.
b.
Will inhibit multiplication ofthe causative agent.
c.
Will stop the activated toxin.
d.
Will stop the activity of adenyl cyclase.
e.
None of the above
55. 1- A 49-year old woman is bitten by her cat on the dorsal aspect of her right index
fingerat 8:00AM. By4:30PMshehasatemperature of38oCandthefingerand
the dorsum of her right hand are red, swollen and painful. An oxidase ~ and
catalase +, gram negative rod with bipolar staining is recovered from an aspirate
of the abscess on her finger. The organism most likely responsible is:
a.
Brucella canis
b.
Pasteurella multocida
c.
Haemophilus inOuenzae
d.
Francisella tularensis
e.
Yersinia enterocolitica
56. A 35-year old man who enjoys huntiogjackrabbits has a sudden onset of
headache, fever, chills and swollen lymph nodes. He also experiences nausea,
vomiting, anabdominal discomfort. A painful papule on his left hand heals over a
period of about six weeks and his lymphadenopathy subsides approximately 4
months later.
Routine blood cultures are negative. \Vhich ufthe following organisms is the most
likely causative agent?
a. Yersinia pestis
b. neisseria gonorrhoeae
c. FrancisclJa tularensis
d. Pasteurella multocida
e. Brucella melitensis
57.
Pathogenic bacteria enter the body by various routes and entry mechanisms are
critical for understanding the pathogenesis and transmissibility of each agent.
"Which one ofthe following is a correct association between a pathogen and its
common entry mechanism?
a.
Neisseria meningitis - sexually transmitted entry
b.
Corynebacterium diphtheriae - food bom entry
c.
Rickettsia rickettsii - entry by contamination ofwolU1d with soil
d.
Clostridium tctani - inhalation entry
e.
Borrelia burgdorferi - arthropod vector-borne entry
58. A 21-year old male visits a sexually transmitted disease clinic with complaints of
a purulent urethral discharge and dysuria. Pus cells, but no bacteria, are noted on
the Gram stain examination ofthe exudate. Which of the following organisms are
the most likely cause the infection?
a.
Neisseria gonorrhoeae and Chlamydia trachomatis
b.
Treponema pallidum and Neisseria gonorrhoeae
c.
Ureaplasma urealyticum and Chlamydia trachomatis
d.
Mycoplasma hominis and Chlamydia psittaci
e. Erlichia chaffeensis and Treponema pallidum
59. Wbich organism listed below is regarded as the classic cause in previously healthy
individual ofatypical pneumonia., characterized by an insidious onset, headache,
non-productive cough and cold agglutinin formation?
a. Chlamydia psittaci
b.
Chlamydia trachomatis
c.
Mycoplasma pneumoniae
d.
Streptococcus pneumoniae
e.
Legionella pnewnophila
60. For which of the following organism is there no known animal reservoir?
a. A Francisella tularensis
b. B. Leptospira interrogans
c. C. Brucella melitensis
d. D. Yersinia pestis
e. Treponema carateuID
6]. Erythema chronicum migrans is a clinical manifestation associated with an
infection caused by
a. Borrelia burgdorferi
b. Francisella Tularensis
c.
Yersinia enterocoIitica
d. BrucelJa abortus
e. Bartonella henselae
62. A 30 years old patient arrives in the emergency room complaining of severe
headache and fevers. The cerebrospinal fluid collected by lumbar puncture present
a yellowish color. You will;
a.
let the patient to recover for 5 hours and then you \\Till repeat the lumbar
puncture.
b. Perform an encephalogran1 and according to the result you will or not begin an
antibiotherapy.
c. begin immediately a treatment with a third-generation cephalosporin
d. begin immediately a treatment with Penicillin G
e. wait the result of cerebrospinal fluid culture then you will give the most
adapted antibiotherapy.
f. do nothing. This is a typical case ofviral meningitis
63. The extracellular stage ofChlamydia trachomatis is known as a
a. endospore.
b.
reticulate body.
c. blastospore.
d. elementary body.
e. vegetative cell.
64. Syphilis and Lyme disease are strinkingly similar in which ofthe following aspects?
a. Their modes of transmission are similar
b. Both diseases display three similar, distinct phases.
c. Both causative agents share many antigenic markers.
d. The diseases show cross immunity
e. Both causative agents can be cultured
65. Postpartum fever due to Mycoplasma hominis js treated with:
a. tetracycline
b. Penicillin G
c.
Cphalosporins
d. vancomycin
e. A combination of Penicillin G and an inhibitor of beta lactamase
66. A man goes camping in the Appalachian Mountains. Within a week after
returning home he has a high fever and a petechial rash that is spreading from his
hands toward his shoulders. This disease was most likely caused by:
a. a gram-negative spirochete.
b. a bacteriwn that lives within the cytoplasm of infected endothelial cells.
c.
a bacterirun with two developmental fonns -one infective and one replicative.
d. a bipolar staining gram negative rod that has been used as an agent ofbioJogical
warfare.
f.
None of the above
67. Blood taken from vein ofpatient with endocarditis can be sterile (or almost
sterile) for the following reasons:
a.
Following colonization in the heart, the microorganisms can be eradicated from
both the heart and the blood. The disease then sustain even in the absence of
the microorganisms.
b.
once colonized in the heart, the microorganism remains firmly attached Lo the
heart tissue.
c. bacteria that cause endocarditis CaDllot be cultured in available tissue cultures.
d. in some cases, microorganisms that circulate outside the heart are destroyed by
the immune system.
e. endocarditis develops regardless ofthe presence ofmicroorganism in the blood.
68. Multiple drugs arc usually prescribed to treat tuberculosis because:
a. there are high loads of bacteria in infected patients.
b. there is not time to determine sensilivities before treatment is initiated.
c. spontaneous mutations can render the bacteria resistant.
d. all of the above
e. none of the above
69. Which of the following sentences best describe sepsis:
a. local response against microorganisms
b. systemic response of the immune system against microorganisms
c. can be induced by various kinds ofmicroorganisms that invade the blood
system.
d. usually associated with patient with underlying other diseases.
e. all the above
f. b+d are corrcect
g. b-f c+d are correct
'/0. Which of the following factors do NOT contribute to the increasing incidence of
sepsIs:
a. old age
b. too competent immune system.
c. compromised immune system.
d. neonate.
e. invasive devices.
f. chemotherapy.
g. inflammatory diseases.
71. Most of the extra-cardiac symptoms of bacterial endocarditis are caused by:
a. damage caused by bacterial exotoxins.
b. septic emboli.
c. lipopolysaccharide (endotoxin).
d. hypo-perfusion.
e. cytotoxicity caused by intracellular bacteria
72 . TIle reservoir of Legionella is:
a. larva of mosquitoes..
b. adult mosquitoes.
c. army veterans
d. humans only.
e. amoeba.
f. birds
73. In unimmwlizerl children suspected of having Diphtheria it is imperative to give
them:
a. the toxoid.
b. anti-diphtheria antibodies.
c. the toxin
d. antibiotics that work on intracellular bacteria.
e. muscle relaxants.
A 2 month old in1ant recently brought to the Emergency Room "With a lO-day history
of coughing spells. The illness had started with a runny nose and some coughing but
had gotten progressively worse in the last week. The baby's coughing was so violent
that he often became cyanotic and gasped for breath when the coughing subsided. In
addition, he had several episodes of vomiting associated with his coughing. His pulse
is rapid, and he is also breathing rapidly. His throat is somewhat red, but contains no
pus, swelling, or gray, membranous structure.
74.
Which disease is bcst fitted to these symptoms?
a. Diphtheria
b. Legionnaires Disease
c. Pertussis
d. Meningitis
c. None of the above.
75. Which of the following courses best describes the ~mcal primary infection with
Mycobacteriwn tuberculosis?
a.
Colonization ofthe upper respiratory tract, followed by aspiration, followed
by severe cough with rust-colored sputum.
b. Hematogenous spread from tissues into the Itmg parenchyma with coughing
up of blood.
c. Direct inhalation into the alveoli with symptomatic disseminated infection
(lymphadenopathy, skin rash, high fever, and disseminated intrava<;cular
coagulation).
d. Direct inhalation into the alveoli with no symptoms ranging to flu-like
symptoms.
e. Colonization ofthe nasopharyJ))( without symptoms for a few years.
76. How does iron affect expression ofDiphieria toxin?
a.
It compromises the bacterial proliferation capacity and indirectly affects the
toxin yield.
b.
Binds the transcriptional activator and enhances its activation capacity.
c.
Binds Ule transcriptional repressor and prevents its repression activity,
d.
It is required for efficient proliferation of the bacteria and indirectly affects the
toxin yield.
e. c+d
77. \\!hat is the major tissue (best studied) that Bordetella pertussis bacteria interacts
with:
a. red blood cells.
b. heart muscle.
c. Nerve.
d. Epithelial cells of the gut.
e. lymph nodes
f. Ciliated ceJls in the nasopharyngeal tract.
'18. Which of the following microorganisms is the most resistant to disinfectants:
a. HIV
b. Polyovirus
c. S. aureus (vep,etative)
d. Mycobacterium
e. E. coli
79. Which of the following parameters affect disinfection/sterilization efficiency?
a. bacterial strain and form (vegetative vs spore).
b. Temperature or disinfectant concentration.
c. Treatment duration.
d. Initial concentration ofcells and spores.
e. AU ofthe above
f. none of the above.
80. The primary tissue infected by M. leprae is:
a. skin
b. peripheral nerve
c. peripheral muscle
d. red blood cells
e. fingers and nose.
Good I.Juck!
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