Bacteriology: Panton-Valentine leukocidin: 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: Panton-Valentine leukocidin

Sample item

A healthy 20-year-old has recurrent painful skin boils. His cousin from the same household develops rapidly progressive necrotising pneumonia with leukopenia after an influenza-like illness. Which virulence factor of the shared community strain is most associated with this picture?

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

The answer and the reasoning

D. Panton-Valentine leukocidin

Panton-Valentine leukocidin is a pore-forming toxin that kills neutrophils and is linked to community-associated MRSA with recurrent furunculosis and necrotising pneumonia, particularly after influenza.

Option by option

  • A. Toxic shock syndrome toxin-1

    TSST-1 is a superantigen that causes toxic shock with rash and desquamation.

  • B. Exfoliative toxin A

    Exfoliative toxin A cleaves desmoglein 1 and causes scalded skin syndrome.

  • C. Enterotoxin B

    Enterotoxin B causes food poisoning with rapid onset vomiting.

  • D. Panton-Valentine leukocidin (correct)

    Correct. PVL lyses leukocytes and causes necrotising pneumonia and recurrent boils.

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.

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Questions about this Microbiology question

What is the answer to this Microbiology question?

The best answer is D, Panton-Valentine leukocidin. Panton-Valentine leukocidin is a pore-forming toxin that kills neutrophils and is linked to community-associated MRSA with recurrent furunculosis and necrotising pneumonia, particularly after influenza.

Why is "Toxic shock syndrome toxin-1" not the answer?

TSST-1 is a superantigen that causes toxic shock with rash and desquamation.

Why is "Exfoliative toxin A" not the answer?

Exfoliative toxin A cleaves desmoglein 1 and causes scalded skin syndrome.

Why is "Enterotoxin B" not the answer?

Enterotoxin B causes food poisoning with rapid onset vomiting.

What concept does this question test?

It tests Bacteriology: Panton-Valentine leukocidin in Microbiology. The correct option holds because: Correct. PVL lyses leukocytes and causes necrotising pneumonia and recurrent boils.

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: Panton-Valentine leukocidin?

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.