Trichophyton Rubrum

Trichophyton rubrum is a fungus that is the most common cause of athlete's foot, jock itch, and ringworm. This fungus was first described by Malmsten in 1845. The growth rate of Trichophyton colonies in the lab can be slow to rather quick. Their texture is waxy, smooth and even to cottony. From the top, the color is white to bright yellowish beige or red violet. Reverse is pale, yellowish, brown, or reddish-brown. Although Trichophyton rubrum is the most common of the dermatophytes causing fingernail fungus infections, there are others. Trichophyton interdigitale is the second most common source of fungal nail infections from the dermatophyte group. (Used to be called Trichophyton mentagrophytes var interdigitale - new guidelines now state that a fungus can only be called T mentagrophytes if it is isolated from an animal - the human varient is T. interdigitale)