Bacteriology: Acinetobacter: 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: Acinetobacter

Sample item

A patient on mechanical ventilation in an ICU for 10 days develops ventilator-associated pneumonia. The endotracheal aspirate grows Gram-negative coccobacilli that are oxidase-negative, non-motile, non-lactose-fermenting and resistant to all carbapenems. Which organism is most likely?

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

The answer and the reasoning

D. Acinetobacter baumannii

Acinetobacter baumannii is an oxidase-negative, non-motile, strictly aerobic coccobacillus that survives on dry surfaces and causes outbreaks of ventilator-associated pneumonia and bacteraemia in ICUs. Carbapenem-resistant strains are widespread in Indian ICUs, and treatment often relies on colistin-based regimens.

Option by option

  • A. Pseudomonas aeruginosa

    Pseudomonas aeruginosa is oxidase-positive and motile with polar flagella.

  • B. Stenotrophomonas maltophilia

    Stenotrophomonas maltophilia is a motile bacillus with polar flagella and intrinsic carbapenem resistance; it is not a coccobacillus.

  • C. Klebsiella pneumoniae

    Klebsiella pneumoniae is a capsulated, lactose-fermenting bacillus, usually susceptible to carbapenems unless it carries carbapenemases.

  • D. Acinetobacter baumannii (correct)

    Correct. Oxidase-negative, non-motile coccobacilli with carbapenem resistance in ventilated patients indicate Acinetobacter.

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, Acinetobacter baumannii. Acinetobacter baumannii is an oxidase-negative, non-motile, strictly aerobic coccobacillus that survives on dry surfaces and causes outbreaks of ventilator-associated pneumonia and bacteraemia in ICUs.

Why is "Pseudomonas aeruginosa" not the answer?

Pseudomonas aeruginosa is oxidase-positive and motile with polar flagella.

Why is "Stenotrophomonas maltophilia" not the answer?

Stenotrophomonas maltophilia is a motile bacillus with polar flagella and intrinsic carbapenem resistance; it is not a coccobacillus.

Why is "Klebsiella pneumoniae" not the answer?

Klebsiella pneumoniae is a capsulated, lactose-fermenting bacillus, usually susceptible to carbapenems unless it carries carbapenemases.

What concept does this question test?

It tests Bacteriology: Acinetobacter in Microbiology. Carbapenem-resistant strains are widespread in Indian ICUs, and treatment often relies on colistin-based regimens.

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: Acinetobacter?

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.