Trichophyton interdigitale is a species of Trichophyton. It can produce penicillin. Some sources equate it with "Trichophyton mentagrophytes". As such, it is one of three common fungi which cause ringworm in companion animals. It is also the second-most commonly isolated fungus causing tinea infections in humans, and the most common or one of the most common fungi that cause zoonotic skin disease (i.e., transmission of mycotic skin disease from species to species). The fungus has a major natural reservoir in rodents, but can also infect pet rabbits, dogs, and horses.