Mycology: Candida krusei: 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: Candida krusei

Sample item

A neutropenic patient on fluconazole prophylaxis develops candidaemia. The blood isolate shows elongated yeast cells with branching pseudohyphae resembling crossed matchsticks on cornmeal agar, and is germ tube negative. Which organism is most likely?

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

The answer and the reasoning

C. Candida krusei

Candida krusei (Pichia kudriavzevii) is intrinsically resistant to fluconazole, so it emerges in patients on azole prophylaxis. It forms elongated cells with crossed-matchstick pseudohyphae and does not produce germ tubes. Echinocandins or amphotericin B are the usual treatment.

Option by option

  • A. Candida parapsilosis

    C. parapsilosis is typically associated with catheters and parenteral nutrition and is usually fluconazole susceptible.

  • B. Candida albicans

    C. albicans is germ tube positive and is generally susceptible to fluconazole.

  • C. Candida krusei (correct)

    Correct. Intrinsic fluconazole resistance and the matchstick morphology fit C. krusei.

  • D. Candida tropicalis

    C. tropicalis is a frequent cause of candidaemia in leukaemia but is usually fluconazole susceptible.

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.

More Microbiology questions

Questions about this Microbiology question

What is the answer to this Microbiology question?

The best answer is C, Candida krusei. Candida krusei (Pichia kudriavzevii) is intrinsically resistant to fluconazole, so it emerges in patients on azole prophylaxis.

Why is "Candida parapsilosis" not the answer?

C. parapsilosis is typically associated with catheters and parenteral nutrition and is usually fluconazole susceptible.

Why is "Candida albicans" not the answer?

C. albicans is germ tube positive and is generally susceptible to fluconazole.

Why is "Candida tropicalis" not the answer?

C. tropicalis is a frequent cause of candidaemia in leukaemia but is usually fluconazole susceptible.

What concept does this question test?

It tests Mycology: Candida krusei in Microbiology. It forms elongated cells with crossed-matchstick pseudohyphae and does not produce germ tubes. Echinocandins or amphotericin B are the usual treatment.

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 Mycology: Candida krusei?

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.