Sporulation from flask-shaped, pigmented projections is comm

Sporulation from flask-shaped, pigmented projections is commonly observed in which one of the following fungi?
A. E. floccosum
B. C. immitis
C. P. verrucosa
D. M. canis
E. B. dermatitidis

The answer is: C
Microscopic examination of fungal isolates is essential to the identification of the organism. Macroscopically, the colonies of Epidermophyton have a yellowish appearance. This fungus 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.

C. immitis is a dimorphic fungus endemic in some regions of the southwestern 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.

Phialophora verrucosa is one of the causes of chromoblastomycosis, a chronic localized infection of the skin and subcutaneous tissue. Microscopically, short or somewhat elongated, flask-shaped, pigmented phialides are seen. The collarettes are vase-shaped and darkly pigmented.

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.

Blastomyces dermatitidis causes a chronic granulomatous disease. The yeast cells are globose or ovoid in shape. The single blastoconidium is attached by a broad base to the parent cell. The following figure illustrates the broad-based budding cells.