Bacteriology: Eikenella in human bite wounds: 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: Eikenella in human bite wounds

Sample item

A man punches another in the mouth and develops a swollen, tender, infected knuckle wound two days later. Gram stain of the pus shows Gram-negative bacilli, and the colonies pit the agar and smell like bleach. Which organism is most likely?

ACapnocytophaga canimorsusBEikenella corrodensCStreptobacillus moniliformisDPasteurella multocida

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

The answer and the reasoning

B. Eikenella corrodens

Eikenella corrodens is part of human oral flora and is a classic cause of infection after clenched-fist injuries and human bites, often with streptococci and anaerobes. It pits the agar and has a bleach-like odour, and amoxicillin-clavulanate is a standard treatment.

Option by option

A. Capnocytophaga canimorsus
Capnocytophaga canimorsus causes severe sepsis after dog bites, especially in asplenic patients.
B. Eikenella corrodens (correct)
Correct. A human oral commensal causing fight-bite infection that pits agar fits Eikenella.
C. Streptobacillus moniliformis
Streptobacillus moniliformis causes rat-bite fever.
D. Pasteurella multocida
Pasteurella multocida follows cat and dog bites and does not pit agar.

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 B, Eikenella corrodens. Eikenella corrodens is part of human oral flora and is a classic cause of infection after clenched-fist injuries and human bites, often with streptococci and anaerobes.

Why is "Capnocytophaga canimorsus" not the answer?

Capnocytophaga canimorsus causes severe sepsis after dog bites, especially in asplenic patients.

Why is "Streptobacillus moniliformis" not the answer?

Streptobacillus moniliformis causes rat-bite fever.

Why is "Pasteurella multocida" not the answer?

Pasteurella multocida follows cat and dog bites and does not pit agar.

What concept does this question test?

It tests Bacteriology: Eikenella in human bite wounds in Microbiology. It pits the agar and has a bleach-like odour, and amoxicillin-clavulanate is a standard treatment.

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: Eikenella in human bite wounds?

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.