Inflammatory-Type Tinea Corporis from Trichophyton mentagrophytes Animal Type 3 with Suspected Infection from a Guinea Pig.

An adlescent girl was bitten on the right middle finger while attempting to intervene in a fight among her three pet guinea pigs. She was initially treated by a local physician without improvement and was subsequently referred to the Department of Dermatology at our hospital. Direct microscopic examination of scales and crusts with KOH was positive, and she was diagnosed with tinea corporis. The isolated fungus was morphologically identified as belonging to the Trichophyton mentagrophytes complex, and topical luliconazole cream was administered. Molecular analysis based on the DNA sequence of the nuclear ribosomal internal transcribed spacer (ITS) 1 region revealed that the isolate belonged to ITS type II, corresponding to T. mentagrophytes animal type 3. These findings strongly suggested zoonotic transmission from the pet guinea pigs. This appears to be one of the very few reported cases of T. mentagrophytes animal type 3 isolated from a human lesion.