Which of the following is a dematiaceous fungus?

• A. Fonsecaea pedrosoi
• B. Candida albicans
• C. Aspergillus fumigatus
• D. Rhizopus oryzae

Answer: (A)

Dematiaceous fungi are pigmented because they have melanin in their cell walls, giving dark brown to black appearances in tissue and culture. Fonsecaea pedrosoi is a classic example and is well known for causing chromoblastomycosis, with pigmented hyphae that reflect this melanin-containing nature. In contrast, Candida albicans is a colorless yeast that forms budding cells and pseudohyphae, not pigmented; Aspergillus fumigatus is a hyaline mold with colorless to pale green spores and lacks melanin-based pigmentation; Rhizopus oryzae also shows nonpigmented, broad, nonseptate hyphae. So the pigment-producing organism among them is Fonsecaea pedrosoi.