MCQ of the Day: 5 November 2026

Subacute meningitis with raised opening pressure in advanced HIV, and capsulated budding yeasts with a clear halo on India ink, indicate cryptococcal meningitis due to Cryptococcus neoformans. Its enzyme phenol oxidase (laccase) converts the diphenolic compounds in Guizotia abyssinica (Niger seed) agar into melanin, giving brown-to-black colonies; this, with rapid urease positivity and growth at 37 °C, supports identification. The cryptococcal antigen (CrAg) lateral flow assay is more sensitive than India ink for diagnosis.
A (Germ tube in serum): identifies Candida albicans (and C. dubliniensis); Cryptococcus does not form germ tubes.
C (Broad pauciseptate right-angle hyphae): describes Mucorales such as Rhizopus; Cryptococcus is a yeast in tissue and culture.
D (Chlamydospores on cornmeal agar): characteristic of C. albicans; Cryptococcus does not form pseudohyphae or chlamydospores.