Trichophyton bullosum: a new zoonotic dermatophyte species

We report the first human case of dermatophytosis caused by Trichophyton bullosum in a 21-year-old male who had a skin lesion located on his forearm. The dermatophyte was isolated in culture and further identified by sequence analysis of internal transcripted spacer regions. The species T. bullosum is a zoophilic dermatophyte rarely isolated from the coat of horses in Africa and Asia. In the present case, it was probably transmitted by contact with an infected donkey in a rural area in France. Antifungal therapy led to remission of the lesion in the patient after 2 months of treatment. T. bullosum ITS region sequences were closely related to those of the African species of Arthroderma benhamiae and grouped in a zoophilic cluster with Trichophyton verrucosum, T. erinacei and the Trichophyton anamorph of A. benhamiae (zoophilic species of the T. mentagrophytes complex). Systematic molecular identification could contribute to an accurate identification of this unusual species.