Clinical microbiology and hospital infection control: NDM treatment: 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 · Clinical microbiology and hospital infection control: NDM treatment

Sample item

A bloodstream Klebsiella pneumoniae isolate from an ICU patient is resistant to meropenem. The EDTA combined disc test is positive and PCR detects blaNDM. Which regimen is rational?

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

The answer and the reasoning

D. Ceftazidime-avibactam plus aztreonam

NDM metallo-beta-lactamases hydrolyse carbapenems and are not inhibited by avibactam. Aztreonam is stable to metallo-enzymes, and avibactam protects it from co-produced ESBL or AmpC enzymes, so the combination is recommended.

Option by option

  • A. Ceftriaxone combined with sulbactam

    Ceftriaxone with sulbactam is hydrolysed by NDM and has no activity here.

  • B. Meropenem-vaborbactam given as monotherapy

    Vaborbactam does not inhibit metallo-beta-lactamases.

  • C. Ceftazidime-avibactam given as monotherapy

    Avibactam does not inhibit metallo-beta-lactamases, so ceftazidime is hydrolysed by NDM.

  • D. Ceftazidime-avibactam plus aztreonam (correct)

    Correct. Aztreonam resists NDM and avibactam protects it from co-produced serine enzymes.

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, Ceftazidime-avibactam plus aztreonam. NDM metallo-beta-lactamases hydrolyse carbapenems and are not inhibited by avibactam.

Why is "Ceftriaxone combined with sulbactam" not the answer?

Ceftriaxone with sulbactam is hydrolysed by NDM and has no activity here.

Why is "Meropenem-vaborbactam given as monotherapy" not the answer?

Vaborbactam does not inhibit metallo-beta-lactamases.

Why is "Ceftazidime-avibactam given as monotherapy" not the answer?

Avibactam does not inhibit metallo-beta-lactamases, so ceftazidime is hydrolysed by NDM.

What concept does this question test?

It tests Clinical microbiology and hospital infection control: NDM treatment in Microbiology. Aztreonam is stable to metallo-enzymes, and avibactam protects it from co-produced ESBL or AmpC enzymes, so the combination is recommended.

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 Clinical microbiology and hospital infection control: NDM treatment?

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.