Antibiotics: ESBL infections: 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 · Antibiotics: ESBL infections

Sample item

A 70-year-old man has urosepsis. Blood culture grows Klebsiella pneumoniae resistant to ceftriaxone and ceftazidime, and an ESBL phenotype is confirmed. Which antibiotic is the most appropriate for this serious infection?

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

The answer and the reasoning

B. Meropenem

Extended-spectrum beta-lactamases hydrolyse penicillins and third-generation cephalosporins but are stable to carbapenems. Carbapenems are therefore the drug of choice for serious ESBL infections. Piperacillin-tazobactam was inferior to meropenem in bacteraemia due to ceftriaxone-resistant organisms.

Option by option

  • A. Piperacillin-tazobactam

    Piperacillin-tazobactam gave higher mortality than meropenem in this setting.

  • B. Meropenem (correct)

    Correct. Carbapenems are stable to ESBL hydrolysis and are standard for serious infection.

  • C. Ceftriaxone at a higher dose

    ESBL enzymes hydrolyse ceftriaxone, and a higher dose does not overcome this.

  • D. Cefepime

    Cefepime is unreliable against ESBL producers because of inoculum-dependent hydrolysis.

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 Pharmacology questions

Questions about this Pharmacology question

What is the answer to this Pharmacology question?

The best answer is B, Meropenem. Extended-spectrum beta-lactamases hydrolyse penicillins and third-generation cephalosporins but are stable to carbapenems.

Why is "Piperacillin-tazobactam" not the answer?

Piperacillin-tazobactam gave higher mortality than meropenem in this setting.

Why is "Ceftriaxone at a higher dose" not the answer?

ESBL enzymes hydrolyse ceftriaxone, and a higher dose does not overcome this.

Why is "Cefepime" not the answer?

Cefepime is unreliable against ESBL producers because of inoculum-dependent hydrolysis.

What concept does this question test?

It tests Antibiotics: ESBL infections in Pharmacology. Carbapenems are therefore the drug of choice for serious ESBL infections. Piperacillin-tazobactam was inferior to meropenem in bacteraemia due to ceftriaxone-resistant organisms.

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 Antibiotics: ESBL infections?

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.