Explore topic-wise MCQs in Microbiology.

This section includes 51 Mcqs, each offering curated multiple-choice questions to sharpen your Microbiology knowledge and support exam preparation. Choose a topic below to get started.

1.

and can be differentiated on the basis of which of the following tests?

A. Decarboxylation of ornithine
B. Fermentation of sucrose and cellobiose
C. Motility at 22°C
D. All of these
Answer» E.
Discussion
2.

Selective media for the isolation of is

A. Hektoen enteric agar
B. agar
C. Xylose lysine deoxycholate agar
D. All of these
Answer» E.
Discussion
3.

The technique(s), used for the assay of heat-labile enterotoxin produced by , is/are

A. Steroid production in Yl mouse adrenal cell culture
B. Morphological changes in Chinese hamster ovary
C. Enzyme-linked immunosorbent assay
D. All of these
Answer» E.
Discussion
4.

Verotoxin 1 of is similar to

A. cholera toxin
B. shiga toxin
C. heat-stable enterotoxin of
D. heat-labile enterotoxin of
Answer» C. heat-stable enterotoxin of
Discussion
5.

Heat-labile enterotoxin of activates

A. guanylate cyclase
B. adenylate cyclase
C. both (a) and (b)
D. none of these
Answer» C. both (a) and (b)
Discussion
6.

Heat-stable enterotoxin of activates

A. adenylate cyclase
B. guanylate cyclase
C. both of the above
D. none of these
Answer» C. both of the above
Discussion
7.

Which of the following species/subspecies of produce indole?

A. subspecies
B. subspecies
C. subspecies
Answer» E.
Discussion
8.

Which of the following serotypes of does not produce HS?

A. Both (a) and (b)
B. None of these
Answer» D.
Discussion
9.

The reaction(s) that is/are usually positive in , is/ are

A. Glucose fermentation
B. Indole reaction
C. Methyl red reaction
D. All of these
Answer» E.
Discussion
10.

Which of the following determine the pathogenicity of ?

A. V and W antigens
B. F1 envelope antigen
C. Production of pigmented colonies on haemin containing media
D. All of these
Answer» E.
Discussion
11.

An enrichment medium for the isolation of is

A. Alkaline peptone water
B. Terathionate broth
C. Selenite F broth
D. none of these
Answer» D. none of these
Discussion
12.

Which of the following serotypes of Salmonella does not produce H2S?
A. <i>S choleraesuis</i>
B. <i>S paratyphi A</i>
C. Both (a) and (b)
D. None of these
Answer» D. None of these
Discussion
13.

Xylose lysine deoxycholate (XLD) agar is better selective medium than the deoxycholate citrate agar (DCA) because
A. it is selective
B. it imparts better growth
C. it contains high salt concentration
D. it is less inhibitory to
E. <i>S. Dysentriae and S. flexneri</i>
Answer» E. <i>S. Dysentriae and S. flexneri</i>
Discussion
14.

Which of the following is the commonest species of Salmonella for causing zoonotic disease?
A. <i>S Indiana</i>
B. <i>S newport</i>
C. <i>S typhimurium</i>
D. <i>S enteritidis</i>
Answer» D. <i>S enteritidis</i>
Discussion
15.

Which of the following media is selective for Salmonella?
A. Thiosulphate citrate bile salt agar
B. Wilson and Blair's brilliant-green bismuth sulphite agar medium
C. Bile salt agar
D. All of the above
Answer» C. Bile salt agar
Discussion
16.

Selective media for the isolation of Shigella is
A. Hektoen enteric agar
B. <i>Salmonella-Shigella</i>
C. agar
D. Xylose lysine deoxycholate agar
E. All of these
Answer» E. All of these
Discussion
17.

The technique(s), used for the assay of heat-labile enterotoxin produced by Escherichia coli, is/are
A. Steroid production in Yl mouse adrenal cell culture
B. Morphological changes in Chinese hamster ovary
C. Enzyme-linked immunosorbent assay
D. All of these
Answer» E.
Discussion
18.

The media which serve(s) as enrichment media for Salmonella is/are
A. Tetrathionate broth
B. Brilliant green tetrathionate broth
C. Selenite-F broth
D. All of these
Answer» E.
Discussion
19.

Primarily human pathogenic bacteria is/are ,
A. <i>Salmonella typhi</i>
B. <i>S paratyphi A</i>
C. <i>S paratyphi B</i>
D. all of these
Answer» E.
Discussion
20.

The bacteria which produce(s) -galactosidase is/are
A. <i>Citrobacter</i>
B. <i>Enterohacter</i>
C. <i>Serratia</i>
D. all of these
Answer» E.
Discussion
21.

Which of the following property(ies), shown by the organisms belong(s) to the family Enterobacteriaceae?
A. They are catalase-positive
B. They are oxidase-negative
C. They ferment glucose
D. All of these
Answer» E.
Discussion
22.

In Widal test, the significant titre for O agglutinins is generally
A. 1:50 or more
B. 1:100 or more
C. 1:150 or more
D. 1:2.00 or more
Answer» C. 1:150 or more
Discussion
23.

Bipolar staining is characteristic of
A. <i>Yersinia pestis</i>
B. <i>Proteus mirabilis</i>
C. <i>Pseudomonas aeruginosa</i>
D. all of these
Answer» B. <i>Proteus mirabilis</i>
Discussion
24.

Spirochaetes exhibit
A. corkscrew-like rotatory movement
B. flexion and extension motility
C. translatory motion
D. all of the above
Answer» E.
Discussion
25.

Species of Shigella which is predominant in India is
A. <i>S sonnei</i>
B. <i>S dysenteriae</i>
C. <i>S boydii</i>
D. <i>S flexneri</i>
Answer» E.
Discussion
26.

Which of the following disease is caused by Yersinia enterocolitica in man?
A. Gastroenteritis
B. Mesenteric lymphadenitis
C. Septicaemia
D. All of these
Answer» E.
Discussion
27.

Which of the following determine the pathogenicity of Yersinia pestis?
A. V and W antigens
B. F1 envelope antigen
C. Production of pigmented colonies on haemin containing media
D. All of these
Answer» E.
Discussion
28.

The most common cause of urinary tract infection in the community is
A. <i>Klebsiella pneumoniae</i>
B. <i>Proteus vulgaris</i>
C. <i>Escherichia coli</i>
D. <i>Citrobacter freundii</i>
Answer» D. <i>Citrobacter freundii</i>
Discussion
29.

Enterobacter can be differentiated from Klebsiella by
A. ornithine positivity
B. motility
C. both (a) and (b)
D. none of these
Answer» D. none of these
Discussion
30.

Heat-labile enterotoxin of Escherichia coli activates
A. guanylate cyclase
B. adenylate cyclase
C. both (a) and (b)
D. none of these
Answer» C. both (a) and (b)
Discussion
31.

The bacteria that is negative for fermentation of mannitol is
A. <i>S flexneri</i>
B. <i>S boydii</i>
C. <i>S dysenteriae</i>
D. <i>S sonnei</i>
Answer» D. <i>S sonnei</i>
Discussion
32.

Prodigiosin (red pigment) is produced by members of genus
A. <i>Hafnia</i>
B. <i>Enterobacter</i>
C. <i>Serratia</i>
D. <i>Cirobacter</i>
Answer» D. <i>Cirobacter</i>
Discussion
33.

Which of the following serotypes of Salmonella can cause gastroenteritis?
A. <i>S enteritidis</i>
B. <i>S newport</i>
C. <i>S typhimurium</i>
D. All of these
Answer» E.
Discussion
34.

An enrichment medium for the isolation of Shigella is
A. Alkaline peptone water
B. Terathionate broth
C. Selenite F broth
D. none of these
Answer» D. none of these
Discussion
35.

Heat-stable enterotoxin of Escherichia coli activates
A. adenylate cyclase
B. guanylate cyclase
C. both of the above
D. none of these
Answer» C. both of the above
Discussion
36.

Which of the following(s) bacteria belong to the family Entero-bacteriaceae?
A. <i>Yersinia</i>
B. <i>Shigella</i>
C. <i>Salmonella</i>
D. All of these
Answer» E.
Discussion
37.

Transmission of bubonic plague is by
A. rat flea
B. inhalation
C. ingestion
D. all of these
Answer» B. inhalation
Discussion
38.

The bacteria, which is more resistant to adverse environmental conditions, is
A. <i>S sonnei</i>
B. <i>S dysenteriae</i>
C. <i>S flexneri</i>
D. <i>S boydii</i>
Answer» B. <i>S dysenteriae</i>
Discussion
39.

The reaction(s) that is/are usually positive in Escherichia coli, is/ are
A. Glucose fermentation
B. Indole reaction
C. Methyl red reaction
D. All of these
Answer» E.
Discussion
40.

Sylvatic plague occurs in
A. mice
B. squirrels
C. chipmunks
D. all of these
Answer» E.
Discussion
41.

Transmission of pneumonic plague from man to man is through
A. inoculation
B. ingestion
C. droplet infection
D. all of these
Answer» D. all of these
Discussion
42.

Which of the following genus belongs to family Spirochaetaceae?
A. <i>Treponema</i>
B. <i>Spirochaeta</i>
C. <i>Borrelia</i>
D. All of these
Answer» E.
Discussion
43.

Which of the following bacteria is/are known as coliform bacilli?
A. <i>Escherichia</i>
B. <i>Klebsiella</i>
C. <i>Enterobacter</i>
D. All of these
Answer» E.
Discussion
44.

The agent(s) which can cause plague is/are
A. <i>Yersinia pestis</i>
B. <i>Proteus mirabilis</i>
C. <i>Pseudomonas aeruginosa</i>
D. All of these
Answer» B. <i>Proteus mirabilis</i>
Discussion
45.

In Yersinia pestis, capsule is best demonstrated in cultures grown at
A. 25 C
B. 29 C
C. 37 C
D. 45 C
Answer» D. 45 C
Discussion
46.

Which of the following can readily kill Salmonellae?
A. Moist heat at 55 C for 20 min
B. Moist heat at 55 C for 10 min
C. Moist heat at 55 C for 30 min
D. Moist heat at 55 C for 1 hr
Answer» E.
Discussion
47.

Example of the pathogenic bacteria is/are
A. <i>L biflexa</i>
B. <i>Lparva</i>
C. <i>Leptospira interrogans</i>
D. All of these
Answer» D. All of these
Discussion
48.

Yersinia enterocolitica and Y. pestis can be differentiated on the basis of which of the following tests?
A. Decarboxylation of ornithine
B. Fermentation of sucrose and cellobiose
C. Motility at 22 C
D. All of these
Answer» E.
Discussion
49.

In Widal test the significant titres for H agglutinins is
A. 1:50 or more
B. 1:100 ormore
C. 1:200 or more
D. 1:400 or more
Answer» D. 1:400 or more
Discussion
50.

Salmonellae can also be killed by
A. pasteurisation
B. chlorination
C. boiling
D. all of these
Answer» E.
Discussion