PHYLOGENETIC CLASSIFICATION OF TRICHOPHYTON-MENTAGROPHYTES COMPLEX STRAINS BASED ON DNA-SEQUENCES OF NUCLEAR RIBOSOMAL INTERNAL TRANSCRIBEDSPACER-1 REGIONS

Using internal transcribed spacer 1 (ITS1) region ribosomal DNA sequen ces from 37 stock strains and clinical isolates provisionally termed T richophyton mentagrophytes complex in Japan, we demonstrated the mutua l phylogenetic relationships of these strains. Members of this complex were classified into 3 ITS1-homologous groups and 13 ITS1-identical g roups by their sequences. ITS1-homologous group I consists of Arthrode rma vanbreuseghemii, T. mentagrophytes human isolates, and several str ains of T. mentagrophytes animal isolates. Five strains of Arthroderma simii form a cluster comprising ITS1-humologous group II. The America no-European and African races of Arthroderma benhamiae, T. mentagrophy tes var, erinacei, and one strain of a T, mentagrophytes animal isolat e constitute ITS1-homologous group III. According to the phylogenetic tree constructed with Trichophyton rubrum as an outgroup, ITS1-homolog ous groups I and II comprised a monophyletic cluster and ITS1-homologo us group III constituted another cluster which was rather distant from the others in the complex. This system was applicable to the phylogen etic analysis of closely related strains. Using this technique, human and animal isolates of T, mentagrophytes were also clearly distinguish able from each other.