Infections: rapidly growing mycobacteria: practice question

A Dermatology 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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Dermatology · Infections: rapidly growing mycobacteria

Sample item

Three weeks after a cosmetic injection, a patient has multiple red, tender, discharging nodules at the injection sites. Routine bacterial cultures are sterile and there is no response to cloxacillin. What is the best next step?

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

The answer and the reasoning

B. AFB smear and mycobacterial culture of aspirate or biopsy

Post-procedural nodules unresponsive to usual antibiotics with sterile routine cultures suggest rapidly growing non-tuberculous mycobacteria such as Mycobacterium fortuitum, chelonae or abscessus. Acid-fast smear and mycobacterial culture with susceptibility testing guide combination therapy, often including clarithromycin. Surgical debridement may be needed.

Option by option

  • A. Start oral fluconazole

    Fluconazole is not directed at the likely cause.

  • B. AFB smear and mycobacterial culture of aspirate or biopsy (correct)

    Correct. Mycobacterial smear and culture is the key step.

  • C. Observe without investigation

    Observation delays diagnosis of an infection that spreads.

  • D. Add a second beta-lactam

    Beta-lactams do not treat atypical mycobacteria.

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 Dermatology question

What is the answer to this Dermatology question?

The best answer is B, AFB smear and mycobacterial culture of aspirate or biopsy. Post-procedural nodules unresponsive to usual antibiotics with sterile routine cultures suggest rapidly growing non-tuberculous mycobacteria such as Mycobacterium fortuitum, chelonae or abscessus.

Why is "Start oral fluconazole" not the answer?

Fluconazole is not directed at the likely cause.

Why is "Observe without investigation" not the answer?

Observation delays diagnosis of an infection that spreads.

Why is "Add a second beta-lactam" not the answer?

Beta-lactams do not treat atypical mycobacteria.

What concept does this question test?

It tests Infections: rapidly growing mycobacteria in Dermatology. Acid-fast smear and mycobacterial culture with susceptibility testing guide combination therapy, often including clarithromycin. Surgical debridement may be needed.

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 Infections: rapidly growing mycobacteria?

Learn each condition by its primary lesion, site and signature sign. Then use the flashcards and the other Dermatology 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.