di Menna et Marples, 1954
Macroscopic morphology
The growth rate of Microsporum distortum colonies is moderate, maturing in 6 to 10 days following inoculation. The texture is velvety to cottony, flat, and often has radial grooves with a raised center. The color from the front is white to tan or buff and yellow tan from the reverse.
Microscopic morphology
Microsporum distortum produces septate hyphae, macroconidia, and abundant microconidia. Macroconidia are typically irregular and distorted. They contain 3 to 10 cells. Microconidia are unicellular, numerous and club-shaped.
Special notes
Microsporum distortum is considered as a variety of Microsporum canis by some authorities. Unlike Microsporum canis, Microsporum distortum produces distorted macroconidia and numerous microconidia.
In vitro hair perforation test is positive. Microsporum distortum differs from Microsporum audouinii by perforating hair and growing profusely on polished rice grains. Microsporum distortum is a rare cause of tinea capitis in human. It primarily infects cats and dogs. The natural reservoir remains unknown and it is mostly associated with South American monkeys.