SOIL DERMATOPHYTES IN MADRAS, INDIA, IN RELATION TO HUMAN RINGWORM

A total of 269 soil samples collected from different habitats in Madra s, India, were screened for the presence of dermatophytes by the hair- baiting technique. Three strains of Trichophyton mentagrophytes and 16 strains of Microsporum gypseum complex were isolated. These strains w ere subjected to the mating experiment. 2/3 soil isolates of Trichophy ton mentagrophytes belonged to Arthroderma vanbreuseghemii (+) mating type, and 1/3 was Arthroderma vanbreuseghemii mating type. Similarly 6 /70 clinical strains of Trichophyton mentagrophytes isolated in our pr evious study also belonged to Arthroderma vanbreuseghemii (+) mating t ype. These 6 strains were isolated from severe cases of tinea capitis in children belonging to rural Madras. The teleomorphic and mating typ e homology between the clinical and soil isolates of T. mentagrophytes suggest that soil may act as reservoir for these organisms. The incom patible clinical strains of T. mentagrophytes var. interdigitale and A . vanbreuseghemii showed DNA homology, thereby establishing the epidem iologic link which supports the above findings.