Clavate macroconidia are characteristic of which one of the following fungi? (AIIMS Nov 2009)
a. Macroscopically, the colonies of Epidermophyton have a yellowish appearance (KHAKI Colored Growth). This dermatophyte invades skin and nails but never hair. On microscopic examination, clavate or paddle-shaped macroconidia are evident, with rounded ends and smooth walls. Microconidia are absent.
b. C. immitis is a dimorphic fungus endemic in some regions of the south western United States and in Latin America. In tissue, the organism exists as a spherule filled with endospores. When grown on solid media, the organism produces barrel-shaped arthroconidia, which stain with lactophenol cotton blue..
c. B. dermatitidis causes a chronic granulomatous disease. The yeast cells are globose or ovoid in shape. The single blastoconidium is attached by broad base to the parent cell.
d. M. canis is a dermatophyte that infects skin and hair but rarely nails. When hair is infected with this organism, it will fluoresce. Microscopic examination of this organism demonstrates rough-walled macroconidia of 8 to 15 cells.