Q&A Microbiology (Bacteriology)

 1. Name a gram positive coccus that is arranged in pairs

Streptococcus pneumoniae

2. Name a bacteria that gives a bile esculin positive test

Enterococcus

3. Meliodosis is caused by?

Burkholderia pseudomallei

4. Why does Staphylococcus form grape like clusters?

In case of Staphylococcus cell division occurs in 3 planes. After cell division the daughter cells remain in close proximity to each other resulting in  formation of a cluster

5. What is MRSA?

Methicillin resistant staphylococcus aureus

It is resistant to all Beta lactam antimicrobials

6. What is MGIT?

Mycobacterium growth indicator tube 

It is an automated culture system for 

Mycobacterium tuberculosis

7. What is the role of Albert stain in staining of Corynebacterium diphtheriae?

Albert's stain is useful to demonstrate bluish black metachromatic granules that are present in Corynebacterium diphtheriae 

8. Describe the diphtheria toxin

Diphtheria toxin is a protein. It is a powerful exotoxin. Diphtheria toxin acts by inhibiting protein synthesis 

9. Name a bacteria that lacks cell wall

Mycoplasma

10. Scrub typhus is caused by?

Orientia tsutsugamushi 

11. Stuart's transport media is used for in case of which bacteria?

Gonococcus

12. Amongst enterobacteriaceae, only two bacteria  are non motile. Name them.

Klebsiella and Shigella

13. Name the gram positive bacilli 

Bacillus

Clostridium

Corynebacterium

Listeria

14. Why does Salmonella produces red colonies with black centres on XLD agar?

Because of H2S production

15. What is the difference between the shapes of meningococcus and gonococcus?

Meningococcus - Lens shape

Gonococcus - Kidney shape

16. Pseudomembrane formation is seen in which disease?

Diphtheria

17. What is bamboo stick appearance?

Long chains of gram positive bacilli

Seen in Bacillus anthracis

18. Lancefield grouping is done for which bacteria?

Beta hemolytic streptocci

Lancefield grouping is done on basis of cell wall carbohydrate antigen

19. Which bacteria is also known as Hansen's bacilli?

Mycobacterium leprae

20. Tumbling motility is seen in?

Listeria monocytogenes

21. What makes Mycobacterium acid fast?

The higher content of mycolic acid in cell wall

Integrity of cell wall

22. What is the typical colony appearance of Mycoplasma?

Fried egg appearance

23. What is ETEC?

Enterotoxigenic E. coli

It causes traveller's diarrhea

24. Q fever is caused by?

Coxiella burnetti

25. Bordetella pertussis causes whooping cough

The clinical course of whooping cough passes through 3 stages. What are those?

Catarrhal phase

Paroxysmal phase

Convalescent stage

26. What is Gas Gangrene?

Gas gangrene is rapidly spreading edematous myonecrosis which occurs when severely crushed wounds get contaminated with pathogenic clostridia. Gas gangrene is always polymicrobial.

27. What is stormy clot reaction?

Clostridium perfringens produces stormy clot reaction in litmus milk. It occurs due to fermentation of lactose which produces acid and vigorous gases.

28. Clostridium tetani produces 2 exotoxins - Tetanolysin and tetanospasmin. Which of them is a neurotoxin that is responsible for clinical manifestations of tetanus?

Tetanospasmin

29. What is Risus sardonicus?

Sustained spasm of facial muscles Which gives an appearance of grinning. It is one of the complications of tetanus.

30. Why does Robertson cooked meat broth allows growth of obligate anaerobes?

RCM broth contains chopped meat particles which provide glutathione and unsaturated fatty acids which take up oxygen and create low redox potential. It thus allows growth of obligate anaerobes.