Mycology: Scedosporium apiospermum: 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 · Mycology: Scedosporium apiospermum

Sample item

A man develops a brain abscess and a lung lesion months after a near-drowning in a pond. Biopsy shows hyaline septate hyphae resembling Aspergillus, but the isolate is resistant to amphotericin B. Which organism is the likely cause?

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

The answer and the reasoning

D. Scedosporium apiospermum

Scedosporium apiospermum (the asexual form of Pseudallescheria boydii) is found in polluted water and soil. It causes mycetoma and disseminated infection after near-drowning, looks like Aspergillus microscopically and is intrinsically resistant to amphotericin B, so voriconazole is preferred.

Option by option

  • A. Aspergillus fumigatus

    A. fumigatus looks similar but is generally amphotericin and voriconazole sensitive, and is not linked to near-drowning.

  • B. Sporothrix schenckii

    S. schenckii is a dimorphic fungus with cigar-shaped yeasts and does not produce septate hyphae in tissue.

  • C. Rhizopus oryzae

    Rhizopus has broad aseptate ribbon-like hyphae.

  • D. Scedosporium apiospermum (correct)

    Correct. Septate hyaline hyphae after near-drowning with amphotericin resistance indicate Scedosporium.

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 D, Scedosporium apiospermum. Scedosporium apiospermum (the asexual form of Pseudallescheria boydii) is found in polluted water and soil.

Why is "Aspergillus fumigatus" not the answer?

A. fumigatus looks similar but is generally amphotericin and voriconazole sensitive, and is not linked to near-drowning.

Why is "Sporothrix schenckii" not the answer?

S. schenckii is a dimorphic fungus with cigar-shaped yeasts and does not produce septate hyphae in tissue.

Why is "Rhizopus oryzae" not the answer?

Rhizopus has broad aseptate ribbon-like hyphae.

What concept does this question test?

It tests Mycology: Scedosporium apiospermum in Microbiology. It causes mycetoma and disseminated infection after near-drowning, looks like Aspergillus microscopically and is intrinsically resistant to amphotericin B, so voriconazole is preferred.

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 Mycology: Scedosporium apiospermum?

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.