A 38-year-old HIV patient with CD4 count of 60 cells/μL presents with headache, fever, and altered sensorium. CSF reveals an India ink preparation showing encapsulated yeast cells with a wide polysaccharide capsule. Which organism is responsible?

• A Candida albicans
• B Aspergillus fumigatus
• C Histoplasma capsulatum
• D Cryptococcus neoformans ✓

Explanation

Cryptococcus neoformans is a yeast with a thick polysaccharide capsule that appears as a clear halo around cells in India ink preparation (negative staining). It is the leading cause of fungal meningitis in HIV/AIDS patients with CD4 < 100 cells/μL. Candida causes thrush and mucosal/systemic infections but lacks a polysaccharide capsule visible by India ink. Aspergillus is a mould (not yeast) and Histoplasma presents as small intracellular yeast in macrophages.

Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.