Bacteriology: rat-bite fever: 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 · Bacteriology: rat-bite fever

Sample item

A laboratory worker bitten by a rat develops fever, a rash on the hands and feet and migratory polyarthritis five days after the healed bite. Blood grows, on serum-enriched medium, a pleomorphic Gram-negative bacillus with bulbous swellings and filaments. Which organism is responsible?

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

The answer and the reasoning

D. Streptobacillus moniliformis

Streptobacillus moniliformis causes Haverhill fever, the form of rat-bite fever with arthritis and rash, and needs enriched medium for growth. Spirillum minus causes the sodoku form, which has a relapsing ulcer and lymphadenitis but little arthritis.

Option by option

  • A. Spirillum minus

    Spirillum minus is a spiral organism, not cultivable, and the sodoku form lacks prominent arthritis.

  • B. Bartonella henselae

    Bartonella henselae causes cat-scratch disease with regional lymphadenitis.

  • C. Pasteurella multocida

    Pasteurella multocida causes rapid cellulitis within 24 hours of a cat or dog bite.

  • D. Streptobacillus moniliformis (correct)

    Correct. Pleomorphic bacilli with bulbous swellings and arthritis after a rat bite indicate S. moniliformis.

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.

More Microbiology questions

Questions about this Microbiology question

What is the answer to this Microbiology question?

The best answer is D, Streptobacillus moniliformis. Streptobacillus moniliformis causes Haverhill fever, the form of rat-bite fever with arthritis and rash, and needs enriched medium for growth.

Why is "Spirillum minus" not the answer?

Spirillum minus is a spiral organism, not cultivable, and the sodoku form lacks prominent arthritis.

Why is "Bartonella henselae" not the answer?

Bartonella henselae causes cat-scratch disease with regional lymphadenitis.

Why is "Pasteurella multocida" not the answer?

Pasteurella multocida causes rapid cellulitis within 24 hours of a cat or dog bite.

What concept does this question test?

It tests Bacteriology: rat-bite fever in Microbiology. Spirillum minus causes the sodoku form, which has a relapsing ulcer and lymphadenitis but little arthritis.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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: rat-bite fever?

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.