Antimicrobials: bactericidal and bacteriostatic: 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: bactericidal and bacteriostatic

Sample item

Which grouping is correct?

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

The answer and the reasoning

A. Aminoglycosides and fluoroquinolones show concentration-dependent killing, whereas beta-lactams show time-dependent killing

For aminoglycosides and fluoroquinolones the peak to MIC ratio determines the effect, while for beta-lactams the time above MIC is key, so frequent or extended infusions help. Tetracyclines, macrolides and chloramphenicol are generally bacteriostatic.

Option by option

  • A. Aminoglycosides and fluoroquinolones show concentration-dependent killing, whereas beta-lactams show time-dependent killing (correct)

    Correct. This is the standard pharmacodynamic grouping.

  • B. Beta-lactams show concentration-dependent killing

    Beta-lactam killing depends on time above MIC.

  • C. Tetracyclines are bactericidal and concentration dependent

    Tetracyclines are bacteriostatic.

  • D. Aminoglycosides are bacteriostatic and time dependent

    Aminoglycosides are bactericidal and concentration dependent.

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 A, Aminoglycosides and fluoroquinolones show concentration-dependent killing, whereas beta-lactams show time-dependent killing. For aminoglycosides and fluoroquinolones the peak to MIC ratio determines the effect, while for beta-lactams the time above MIC is key, so frequent or extended infusions help.

Why is "Beta-lactams show concentration-dependent killing" not the answer?

Beta-lactam killing depends on time above MIC.

Why is "Tetracyclines are bactericidal and concentration dependent" not the answer?

Tetracyclines are bacteriostatic.

Why is "Aminoglycosides are bacteriostatic and time dependent" not the answer?

Aminoglycosides are bactericidal and concentration dependent.

What concept does this question test?

It tests Antimicrobials: bactericidal and bacteriostatic in Pharmacology. Tetracyclines, macrolides and chloramphenicol are generally bacteriostatic.

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: bactericidal and bacteriostatic?

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.