This set of Microbiology Multiple Choice Questions & Answers (MCQs) focuses on “Diseases Caused by Staphylococcus, Streptococcus and Bacillus”.
1. Which of the following toxins cause damage to the tissue cells by its phospholipase action?
a) alpha toxin
b) delta toxin
c) protein A
d) coagulase
View Answer
Explanation: Delta toxin damages tissue cells by its action as a phospholipase. It is produced by human strains of S. aureus.
2. Which of the following microorganism causes lesions in the form of abscesses?
a) Staphylococcus aureus
b) Streptococcus pyogenes
c) Streptococcus pneumoniae
d) Clostridium perfringens
View Answer
Explanation: Staphylococcus aureus causes localized infections in which the characteristic lesion is a walled-off fort called the abscess— a cavity filled with pus cells (neutrophils), dead tissue, and bacteria.
3. Antibiotics can easily reach the staphylococci.
a) True
b) False
View Answer
Explanation: Antibiotics have difficulty in reaching the staphylococci and may have to be administered to a patient for a long period in order to be effective.
4. Streptococus pyogenes comprises which Lancefield group?
a) A
b) B
c) C
d) D
View Answer
Explanation: Streptococus pyogenes comprises Lancefield group A. This organism causes several diseases like sore throat, scarlet fever etc.
5. Which of the following microbe does not belong to Group D enterococci group?
a) S. faecalis
b) S. faecium
c) S. durans
d) S. bovis
View Answer
Explanation: S. bovis belongs to Group D nonenterococci group. All other above microbes belong to Group D enterococci group.
6. Scarlet fever is similar to the pharyngitis in all respects.
a) True
b) False
View Answer
Explanation: Scarlet fever is similar to the pharyngitis except for the skin rash that appears because of the erythrogenic toxin.
7. Which of the following immunity is protective against infection by S.pyogenes?
a) cell-mediated immunity
b) antigen-antibody immunity
c) humoral immunity
d) no cure present
View Answer
Explanation: The only type of immunity that is protective against infection by S. pyogenes is humoral immunity: antibodies against M proteins act as opsonins, enhancing phagocytosis of the streptococci.
8. Puerperal fever is a streptococcal infection of the ______________
a) kidney
b) skin
c) uterus
d) heart
View Answer
Explanation: Puerperal fever, sometimes called puerperal sepsis, is a streptococcal infection of the uterus of a mother and is acquired at childbirth.
9. Which of the following is a major virulence factor of Streptococcus pneumoniae?
a) polysaccharide capsule
b) M protein
c) streptolysin O
d) streptolysin S
View Answer
Explanation: The major virulence factor is the polysaccharide capsule, which effectively inhibits phagocytosis.
10. Which drug is used for the treatment of anthrax?
a) erythromycin
b) penicillin
c) tetracycline
d) ampicillin
View Answer
Explanation: Penicillin is the drug of choice for the treatment of anthrax. A live attenuated vaccine is available for prevention of anthrax in cattle and sheep.
Sanfoundry Global Education & Learning Series – Microbiology.
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