Genetic relationship between Trichophyton mentagrophytes var. interdigitale and Arthroderma vanbreuseghemii.

Thirty-nine Arthroderma vanbreuseghemii isolates identified by mating behavior were assayed to determine their ribosomal RNA gene internal transcribed spacer (ITS) region genotypes. Twenty-two isolates of mating type (+) and 4 of (-) showed the genotype of Trichophyton mentagrophytes var. interdigitale, 9 isolates of mating type (+) and 4 of (-) showed the genotype of A. vanbreuseghemii. Nine of 14 isolates with granular or asteroid colony morphology showed the genotype of T. mentagrophytes var. interdigitale. There was no relation between ITS genotype and morphology or mating type of the isolates. Isolates of T. mentagrophytes var. interdigitale genotype were shown to include non-sexually degenerate zoophilic strains with granular colony morphology as well as sexually and morphologically degenerate anthropophilic strains and may be just one genotype of a heterogeneous species, A. vanbreuseghemii.