Bacteriology: infant botulism: 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: infant botulism

Sample item

A 5-month-old breastfed infant has had constipation for 4 days and now has a weak cry, poor suck, drooping eyelids and generalised hypotonia. The parents had been giving a spoonful of honey. Which statement explains the pathogenesis?

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

The answer and the reasoning

B. Ingested spores germinate and colonise the immature gut, producing toxin in situ

In infant botulism, Clostridium botulinum spores in honey or dust germinate in the infant colon, which lacks a mature protective flora, and the toxin produced locally is absorbed. Botulinum toxin cleaves SNARE proteins and blocks acetylcholine release, causing flaccid paralysis. Honey should be avoided before 1 year of age, and treatment is supportive with human botulism immune globulin.

Option by option

  • A. Preformed toxin in the honey is absorbed from the gut

    Absorption of preformed toxin describes food-borne botulism in older children and adults.

  • B. Ingested spores germinate and colonise the immature gut, producing toxin in situ (correct)

    Correct. Colonisation and in situ toxin production is the mechanism specific to infants.

  • C. Toxin enters through a contaminated umbilical stump

    Wound or umbilical entry describes wound botulism or neonatal tetanus, not this presentation.

  • D. Endotoxin is released from overgrown Gram-negative gut flora

    Endotoxin from Gram-negative organisms does not cause descending flaccid paralysis.

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 B, Ingested spores germinate and colonise the immature gut, producing toxin in situ. In infant botulism, Clostridium botulinum spores in honey or dust germinate in the infant colon, which lacks a mature protective flora, and the toxin produced locally is absorbed.

Why is "Preformed toxin in the honey is absorbed from the gut" not the answer?

Absorption of preformed toxin describes food-borne botulism in older children and adults.

Why is "Toxin enters through a contaminated umbilical stump" not the answer?

Wound or umbilical entry describes wound botulism or neonatal tetanus, not this presentation.

Why is "Endotoxin is released from overgrown Gram-negative gut flora" not the answer?

Endotoxin from Gram-negative organisms does not cause descending flaccid paralysis.

What concept does this question test?

It tests Bacteriology: infant botulism in Microbiology. Botulinum toxin cleaves SNARE proteins and blocks acetylcholine release, causing flaccid paralysis. Honey should be avoided before 1 year of age, and treatment is supportive with human botulism immune globulin.

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: infant botulism?

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.