250+ TOP MCQs on Infection Process – Events in Infection Following Penetration and Answers

Microbiology Question Bank focuses on “Infection Process – Events in Infection Following Penetration”.

1. Gas gangrene is caused by which of the following microorganisms?
A. Staphylococcus aureus
B. Clostridium perfringens
C. Pseudomonas aeruginosa
D. E.coli
Answer: B
Clarification: Anaerobic bacteria, Clostridium perfringens, causes wound infection gas gangrene.

2. The characteristic lesion, abscess caused by Staphylococcus aureus is a type of non-localized infection.
A. True
B. False
Answer: B
Clarification: The characteristic lesion, abscess caused by Staphylococcus aureus, is a walled-off cavity in the tissues containing the staphylococci, numerous white blood cells, etc. This is a type of localized infection.

3. Which of the following condition is false for tissue invasion by C.perfringens?
A. anaerobic condition of the wound
B. production of large amounts of hydrogen gas
C. production of small amounts of hydrogen gas
D. release of toxins
Answer: C
Clarification: Production of large amounts of hydrogen gas by the bacteria contributes to the rapidity of tissue invasion.

4. Amputation is the only way to stop the spread of C.perfringens to the rest of the body.
A. True
B. False
Answer: A
Clarification: Amputation of an affected limb is often the only way to stop the spread of C.perfringens to the rest of the body.

5. What is the shape of the lymph nodes?
A. tubular
B. circular
C. cuboidal
D. ovoid
Answer: D
Clarification: Lymph nodes are ovoid structures ranging in size from one to several millimeters and are widely distributed throughout the body.

6. Lymph enters a lymph node by several _________________
A. lymphatic trunks
B. lymphatic vessels
C. lymphatic ducts
D. arteries
Answer: B
Clarification: Lymph enters a lymph node by any of several lymphatic vessels, passes through the lymph node along tortuous, winding channels, and emerges via a single efferent lymph vessel.

7. Which microbe causes the disease erysipelas?
A. S. pyogenes
B. C. perfringens
C. Pseudomonas aeruginosa
D. E.coli
Answer: A
Clarification: Erysipelas, an inflammatory disease of the skin is caused by S. pyogenes. The painful lesions are spread by invasion of the lymphatic system of the subepidermal tissue.

8. Which of the following is not the characteristic of a bubo?
A. inflamed
B. sore when infected
C. small
D. free from bacteria
Answer: C
Clarification: The lymph node removes nearly all of the bacteria that enters it, and it may become inflamed, enlarged, and sore when infected and in this condition it is sometimes called a bubo.

9. Where does Neisseria meningitidis reach after entering the body?
A. kidney
B. intestine
C. nasopharynx
D. meninges
Answer: D
Clarification: Neisseria meningitidis present in the nasopharynx can reach the meninges (membranes that cover the brain and spinal corD. by means of transient bacteremia.

10. Which of the following microorganism can cause acute renal failure?
A. Leptospira
B. Salmonella typhi
C. Neisseria meningitidis
D. Bacillus anthracis
Answer: A
Clarification: By means of bacteremia, spirochetes of the genus Leptospira can reach the kidneys, where they may eventually cause acute renal failure.

11. Which of the following disease is caused by the pathogen directly infecting the lymphatic system?
A. meningitis
B. typhoid fever
C. renal failure
D. anemia
Answer: B
Clarification: In typhoid fever, Salmonella typhi after penetrating through the epithelial cells, enter the lymphatic system, and reach the mesenteric lymph nodes.

12. Which of the following disease is an example of septicemic infection?
A. typhoid fever
B. meningitis
C. anthrax
D. renal failure
Answer: C
Clarification: Anthrax is an example of septicemic infection in which the number of Bacillus anthracis organisms may often exceed the number of erythrocytes in the blood.

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