A chronic pulmonary infection in a farmer from Brazil yields a yeast on biopsy showing multiple buds attached to the central cell by narrow necks, resembling a ship's steering wheel. Which organism produces this appearance?
- A Histoplasma capsulatum
- B Blastomyces dermatitidis
- C Paracoccidioides brasiliensis ✓
- D Cryptococcus neoformans
Correct answer: C. Paracoccidioides brasiliensis
Explanation
The pilot-wheel or mariner's-wheel appearance of multiple daughter buds arranged around a central mother cell is pathognomonic of Paracoccidioides brasiliensis yeast phase in tissue. Blastomyces shows single broad-based buds, Histoplasma shows small intracellular yeasts with narrow-based budding inside macrophages, and Cryptococcus shows encapsulated yeasts with narrow-based buds surrounded by a halo. Recognising these distinct budding patterns is a standard examination point in systemic mycoses.
Reference: Ananthanarayan and Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.