Bacteriology: Capnocytophaga canimorsus: 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: Capnocytophaga canimorsus

Sample item

A 58-year-old splenectomised man with alcohol use disorder develops fulminant sepsis with purpura and DIC one day after a dog bite. Blood culture eventually grows slow-growing fusiform Gram-negative bacilli that need carbon dioxide. Which organism is most likely?

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

The answer and the reasoning

C. Capnocytophaga canimorsus

Capnocytophaga canimorsus lives in canine mouths and causes overwhelming sepsis after dog bites in asplenic or alcoholic patients. It grows slowly in a carbon dioxide-rich atmosphere, and amoxicillin-clavulanate is a standard choice.

Option by option

  • A. Francisella tularensis

    F. tularensis follows handling of rabbits or tick bites and gives ulceroglandular disease.

  • B. Pasteurella multocida

    P. multocida usually causes rapid cellulitis within 24 hours and is only occasionally septicaemic.

  • C. Capnocytophaga canimorsus (correct)

    Correct. Asplenic fulminant sepsis after a dog bite with a capnophilic bacillus indicates C. canimorsus.

  • D. Bartonella henselae

    B. henselae causes cat-scratch disease with regional lymphadenopathy.

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 C, Capnocytophaga canimorsus. Capnocytophaga canimorsus lives in canine mouths and causes overwhelming sepsis after dog bites in asplenic or alcoholic patients.

Why is "Francisella tularensis" not the answer?

F. tularensis follows handling of rabbits or tick bites and gives ulceroglandular disease.

Why is "Pasteurella multocida" not the answer?

P. multocida usually causes rapid cellulitis within 24 hours and is only occasionally septicaemic.

Why is "Bartonella henselae" not the answer?

B. henselae causes cat-scratch disease with regional lymphadenopathy.

What concept does this question test?

It tests Bacteriology: Capnocytophaga canimorsus in Microbiology. It grows slowly in a carbon dioxide-rich atmosphere, and amoxicillin-clavulanate is a standard choice.

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: Capnocytophaga canimorsus?

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.