Bacteriology: Campylobacter: 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.

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Microbiology · Bacteriology: Campylobacter

Sample item

A 28-year-old man has bloody diarrhoea and cramps after eating undercooked chicken. Ten days later he develops ascending symmetrical limb weakness with areflexia. Which culture conditions would have isolated the organism responsible for the preceding diarrhoea?

ASelective medium, 42 degrees C, microaerophilic atmosphereBCold enrichment in broth at 4 degrees C for several weeksCRobertson cooked meat medium incubated anaerobically at 37 degrees CDMacConkey agar incubated aerobically at 37 degrees C

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

The answer and the reasoning

A. Selective medium, 42 degrees C, microaerophilic atmosphere

Campylobacter jejuni is a curved, motile Gram-negative rod that is microaerophilic and thermophilic, and it grows best at 42 degrees C on selective media such as Skirrow or CCDA. It is the commonest antecedent infection of Guillain-Barre syndrome because of molecular mimicry between its lipo-oligosaccharide and neural gangliosides.

Option by option

A. Selective medium, 42 degrees C, microaerophilic atmosphere (correct)
Correct. Microaerophilic incubation at 42 degrees C selects for Campylobacter and suppresses other faecal flora.
B. Cold enrichment in broth at 4 degrees C for several weeks
Cold enrichment is used to recover Listeria and Yersinia enterocolitica, not Campylobacter.
C. Robertson cooked meat medium incubated anaerobically at 37 degrees C
Anaerobic incubation is needed for clostridia and Bacteroides; Campylobacter requires reduced oxygen, not its absence.
D. MacConkey agar incubated aerobically at 37 degrees C
Aerobic growth on MacConkey agar suits lactose fermenters and Enterobacterales; Campylobacter does not grow well in air.

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, Selective medium, 42 degrees C, microaerophilic atmosphere. Campylobacter jejuni is a curved, motile Gram-negative rod that is microaerophilic and thermophilic, and it grows best at 42 degrees C on selective media such as Skirrow or CCDA.

Why is "Cold enrichment in broth at 4 degrees C for several weeks" not the answer?

Cold enrichment is used to recover Listeria and Yersinia enterocolitica, not Campylobacter.

Why is "Robertson cooked meat medium incubated anaerobically at 37 degrees C" not the answer?

Anaerobic incubation is needed for clostridia and Bacteroides; Campylobacter requires reduced oxygen, not its absence.

Why is "MacConkey agar incubated aerobically at 37 degrees C" not the answer?

Aerobic growth on MacConkey agar suits lactose fermenters and Enterobacterales; Campylobacter does not grow well in air.

What concept does this question test?

It tests Bacteriology: Campylobacter in Microbiology. It is the commonest antecedent infection of Guillain-Barre syndrome because of molecular mimicry between its lipo-oligosaccharide and neural gangliosides.

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 Bacteriology: Campylobacter?

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.