Experimental tinea pedis induced by non-abrasive inoculation of Trichophyton mentagrophytes arthrospores on the plantar part of a guinea pig foot.

Arthrospores of Trichophyton mentagrophytes were inoculated on to the plantar part of a guinea pig foot by a newly devised non-abrasive method. Anthropophilic and zoophilic isolates required inocula of 280 and 80 arthrospores to infect 50% of inoculated feet, but much larger inocula (5 X 10(4)) were used to establish infection consistently in all feet. Anthropophilic isolate NTM-105 invaded only the upper two-thirds of the horny layer and induced no inflammatory responses. On the other hand, zoophilic isolate SM-110 invaded the whole horny layer and provoked strong inflammatory responses and clinical manifestations. Although the histological features and modes of fungal spreading in the guinea pig skin were quite different between anthropophilic and zoophilic isolate infections, infecting fungi were always recognized in the stratum corneum of all inoculated feet throughout the observation period longer than 6 months. Thus, two types of persistent infections with T. mentagrophytes were established as a guinea pig model of tinea pedis.