General microbiology: transport media: practice question

A Microbiology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

Try it

Microbiology · General microbiology: transport media

Sample item

During a suspected cholera outbreak in a remote village, rectal swabs have to be sent to a district laboratory 8 hours away without refrigeration. Which transport medium is most appropriate?

ACary-Blair mediumBBuffered glycerol salineCRobertson cooked meat mediumDThioglycollate broth

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Cary-Blair medium

Cary-Blair is a semi-solid, buffered, low-nutrient transport medium that preserves Vibrio cholerae, Salmonella and Shigella in stool for days at ambient temperature. Alkaline peptone water is used for enrichment rather than long transport. Buffered glycerol saline suits Shigella but acidifies and kills Vibrio.

Option by option

A. Cary-Blair medium (correct)
Correct. Cary-Blair keeps vibrios viable at room temperature during transport.
B. Buffered glycerol saline
Buffered glycerol saline is used for Shigella and is unsuitable for Vibrio.
C. Robertson cooked meat medium
Robertson cooked meat medium maintains clostridia and other anaerobes.
D. Thioglycollate broth
Thioglycollate broth is a general enrichment medium for anaerobes and aerobes, not a stool transport medium.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Microbiology question

What is the answer to this Microbiology question?

The best answer is A, Cary-Blair medium. Cary-Blair is a semi-solid, buffered, low-nutrient transport medium that preserves Vibrio cholerae, Salmonella and Shigella in stool for days at ambient temperature.

Why is "Buffered glycerol saline" not the answer?

Buffered glycerol saline is used for Shigella and is unsuitable for Vibrio.

Why is "Robertson cooked meat medium" not the answer?

Robertson cooked meat medium maintains clostridia and other anaerobes.

Why is "Thioglycollate broth" not the answer?

Thioglycollate broth is a general enrichment medium for anaerobes and aerobes, not a stool transport medium.

What concept does this question test?

It tests General microbiology: transport media in Microbiology. Alkaline peptone water is used for enrichment rather than long transport. Buffered glycerol saline suits Shigella but acidifies and kills Vibrio.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study General microbiology: transport media?

Make a one-line identity card for each organism: shape and stain, defining test, toxin, disease and drug. Then use the flashcards and the other Microbiology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.