A 50-year-old man with chronic obstructive pulmonary disease on long-term prednisolone presents with fever, cough, and hemoptysis. Sputum KOH mount shows broad, non-septate hyphae with wide-angle (90-degree) branching. Which organism is most likely?

• A Aspergillus fumigatus
• B Candida albicans
• C Fusarium species
• D Mucor/Rhizopus species ✓

Explanation

Mucorales (Mucor, Rhizopus) characteristically show broad (6-25 µm), pauciseptate or non-septate hyphae with irregular, wide-angle (45-90 degree) branching on KOH mount. Aspergillus shows narrow, septate hyphae with regular acute-angle (45 degree) branching. Candida shows budding yeast with pseudohyphae. Fusarium shows septate hyphae with both acute and wide branching but is thinner and more regular than Mucorales.

Reference: Jawetz, Melnick, and Adelberg's Medical Microbiology, 28th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.