Hospital infection control: surgical prophylaxis: 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 · Hospital infection control: surgical prophylaxis

Sample item

A 62-year-old woman is scheduled for elective total hip replacement, and the team plans cefazolin prophylaxis. When should the dose be given for maximum benefit in preventing surgical site infection?

AThe evening before surgery, with a second dose in the morningBAfter skin closure in the recovery roomCWithin 60 minutes before skin incisionDDaily for 5 days after the operation

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

The answer and the reasoning

C. Within 60 minutes before skin incision

Prophylactic antibiotics are effective only if tissue levels are adequate at the time of incision, so the dose is given within 60 minutes before incision (up to 120 minutes for vancomycin or fluoroquinolones), with redosing for long operations or high blood loss. Prophylaxis is stopped within 24 hours of the end of surgery, and prolonged courses add resistance and toxicity without benefit.

Option by option

A. The evening before surgery, with a second dose in the morning
Pre-operative evening dosing leaves low tissue levels at incision and encourages colonisation by resistant flora.
B. After skin closure in the recovery room
A dose after closure misses the period when the wound is exposed.
C. Within 60 minutes before skin incision (correct)
Correct. Giving the drug within 60 minutes before incision ensures effective tissue levels during contamination.
D. Daily for 5 days after the operation
Prolonged post-operative courses add resistance and adverse effects without further benefit.

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.

Questions about this Microbiology question

What is the answer to this Microbiology question?

The best answer is C, Within 60 minutes before skin incision. Prophylactic antibiotics are effective only if tissue levels are adequate at the time of incision, so the dose is given within 60 minutes before incision (up to 120 minutes for vancomycin or fluoroquinolones), with redosing for long operations or high blood loss.

Why is "The evening before surgery, with a second dose in the morning" not the answer?

Pre-operative evening dosing leaves low tissue levels at incision and encourages colonisation by resistant flora.

Why is "After skin closure in the recovery room" not the answer?

A dose after closure misses the period when the wound is exposed.

Why is "Daily for 5 days after the operation" not the answer?

Prolonged post-operative courses add resistance and adverse effects without further benefit.

What concept does this question test?

It tests Hospital infection control: surgical prophylaxis in Microbiology. Prophylaxis is stopped within 24 hours of the end of surgery, and prolonged courses add resistance and toxicity without benefit.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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 Hospital infection control: surgical prophylaxis?

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.