Microbiology Questions and Answers for Campus interviews focuses on “Diseases Caused by Clostridium, Corynebacterium and Mycobacterium”.
1. Which of the following organisms produces neurotoxin as a virulence factor?
A. Bacillus anthracis
B. Clostridium tetani
C. Streptococcus pneumoniae
D. Staphylococcus aureus
Answer: B
Clarification: Clostridium tetani produces only one virulence factor which is a powerful neurotoxin. It is the causative agent of tetanus.
2. Booster immunizations should be given every 10 years.
A. True
B. False
Answer: A
Clarification: Booster immunizations should be given every 10 years to maintain an adequate level of antitoxin to protect against tetanus.
3. Clostridium perfringens type A occurs as a natural flora of ______________
A. stomach
B. mouth
C. intestine
D. eyes
Answer: C
Clarification: Clostridium perfringens type A occurs as part of the normal flora of the human intestine.
4. __________________ is a hyaluronidase that may aid invasiveness of C.perfringens.
A. alpha toxin
B. theta toxin
C. µ toxin
D. √ toxin
Answer: C
Clarification: The µ toxin is a virulence factor produced by C.perfringens and is a hyaluronidase that may aid invasiveness.
5. What pressure of oxygen is used in the treatment involving the use of hyperbaric oxygen?
A. 1
B. 5
C. 100
D. 3
Answer: D
Clarification: In the treatment involving the use of hyperbaric oxygen, the patient is placed in a chamber containing 3 atmospheres pressure of pure oxygen several times a day for half-hour periods.
6. Which of the following temperature is suitable for the multiplication of clostridia spores?
A. 109 to116 degree F
B. 100 degree F
C. -2 to 16 degree F
D. 30-40 degree F
Answer: A
Clarification: If the meat or poultry is cooked at a temperature that does not kill the spores and is subsequently kept at a temperature of 109 to 116 degree F for atleast 2 hours, the clostridia may multiply.
7. Which serovar of C. botulinum occurs mainly in the sediments of the Great Lakes?
A. A
B. B
C. E
D. F
Answer: C
Clarification: Serovar E occurs mainly in the sediments of Great Lakes and along the coasts of western North America and northern Japan.
8. Patients with botulism are treated with monovalent antitoxin.
A. True
B. False
Answer: B
Clarification: Patients with botulism are treated with polyvalent antitoxin (i.e., antitoxin against toxin types A, B, and E) to neutralize any toxin that has not yet become fixed to nerve tissue.
9. Toxin A involved in pseudomembranous colitis is a type of _______________
A. endotoxin
B. enterotoxin
C. cytotoxin
D. neurotoxin
Answer: B
Clarification: Toxin A is an enterotoxin which causes fluid accumulation in the bowel. It is a type of exotoxin and is involved in pseudomembranous colitis.
10. Which of the following inactivates IgA antibodies?
A. Cord factor
B. Diphthin
C. Neuroaminidase
D. K antigens
Answer: B
Clarification: Diphthin is a protease which inactivates IgA antibodies. It is a virulence factor produced by C.diphtheriae.
11. Erythrasma is caused by which of the following microorganism?
A. Corynebacterium diphtheriae
B. Corynebacterium ulcerans
C. Corynebacterium minutissimum
D. Listeria monocytogenes
Answer: C
Clarification: Corynebacterium minutissimum is a species which causes a skin disease called erythrasma.
12. Schick Test is used for detection of which of the following disease?
A. Diphtheria
B. Tuberculosis
C. Erythrasma
D. Botulism
Answer: A
Clarification: The detection of persons susceptible to diphtheria by means of the Schick test has made the disease rare in the US. It is performed by infection of a very small amount of diphtheria toxin into the skin.
13. Which among the following species causes tuberculosis?
A. Mycobacterium leprae
B. Mycobacterium kansasii
C. Mycobacterium bovis
D. Mycobacterium ulcerans
Answer: C
Clarification: M.bovis and M. tuberculosis are pathogenic species and both cause tuberculosis. They regularly exhibit susceptibility to antituberculosis drugs.
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