Antimicrobial resistance: ESBL: 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 · Antimicrobial resistance: ESBL

Sample item

An Escherichia coli isolate is reported as an extended-spectrum beta-lactamase producer. What resistance mechanism is most characteristic?

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

The answer and the reasoning

B. Hydrolysis of many extended-spectrum cephalosporins

ESBL enzymes hydrolyse many penicillins and extended-spectrum cephalosporins, though specific susceptibility testing guides therapy. They are often plasmid mediated and may coexist with resistance to other drug classes.

Option by option

  • A. Methylation of 23S rRNA only

    23S rRNA methylation can confer macrolide resistance but is not the ESBL mechanism.

  • B. Hydrolysis of many extended-spectrum cephalosporins (correct)

    Correct. Enzymatic beta-lactam hydrolysis defines ESBL production.

  • C. Inhibition of folate synthesis

    Folate-pathway inhibition describes sulfonamides or trimethoprim, not bacterial resistance here.

  • D. Altered ergosterol synthesis

    Ergosterol is a fungal membrane target.

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 B, Hydrolysis of many extended-spectrum cephalosporins. ESBL enzymes hydrolyse many penicillins and extended-spectrum cephalosporins, though specific susceptibility testing guides therapy.

Why is "Methylation of 23S rRNA only" not the answer?

23S rRNA methylation can confer macrolide resistance but is not the ESBL mechanism.

Why is "Inhibition of folate synthesis" not the answer?

Folate-pathway inhibition describes sulfonamides or trimethoprim, not bacterial resistance here.

Why is "Altered ergosterol synthesis" not the answer?

Ergosterol is a fungal membrane target.

What concept does this question test?

It tests Antimicrobial resistance: ESBL in Microbiology. They are often plasmid mediated and may coexist with resistance to other drug classes.

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 Antimicrobial resistance: ESBL?

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.