Antimicrobials: sulbactam activity against Acinetobacter: practice question

A Pharmacology 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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Pharmacology · Antimicrobials: sulbactam activity against Acinetobacter

Sample item

Ampicillin-sulbactam is used in severe infection with Acinetobacter baumannii mainly for its sulbactam component rather than for its beta-lactamase inhibition. What explains its usefulness?

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

The answer and the reasoning

C. Intrinsic activity of sulbactam on Acinetobacter penicillin-binding proteins

Besides inhibiting beta-lactamases, sulbactam binds penicillin-binding proteins of Acinetobacter and kills the organism by itself. For this reason high-dose sulbactam is a core option for carbapenem-resistant strains. The ampicillin component adds little.

Option by option

  • A. Inhibition of efflux pumps within the organism

    Efflux pump inhibition is not an established action of sulbactam.

  • B. Inhibition of metallo-beta-lactamases

    Sulbactam does not inhibit metallo-beta-lactamases.

  • C. Intrinsic activity of sulbactam on Acinetobacter penicillin-binding proteins (correct)

    Correct. Sulbactam has direct activity on Acinetobacter penicillin-binding proteins.

  • D. Improved porin penetration of ampicillin

    Porin penetration is not the mechanism of its activity here.

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 Pharmacology question

What is the answer to this Pharmacology question?

The best answer is C, Intrinsic activity of sulbactam on Acinetobacter penicillin-binding proteins. Besides inhibiting beta-lactamases, sulbactam binds penicillin-binding proteins of Acinetobacter and kills the organism by itself.

Why is "Inhibition of efflux pumps within the organism" not the answer?

Efflux pump inhibition is not an established action of sulbactam.

Why is "Inhibition of metallo-beta-lactamases" not the answer?

Sulbactam does not inhibit metallo-beta-lactamases.

Why is "Improved porin penetration of ampicillin" not the answer?

Porin penetration is not the mechanism of its activity here.

What concept does this question test?

It tests Antimicrobials: sulbactam activity against Acinetobacter in Pharmacology. For this reason high-dose sulbactam is a core option for carbapenem-resistant strains. The ampicillin component adds little.

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 Antimicrobials: sulbactam activity against Acinetobacter?

Learn drugs as classes, then the exception in each class that an examiner would pick. Then use the flashcards and the other Pharmacology 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.