The first isolation of Arthroderma benhamiae in Japan

A clinical isolate of Trichophyton mentagrophytes from rabbit was examined by polymerase chain reaction (PCR) analysis and a mating experiment. The species-specific primers designed from the nucleotide sequences of the chitin synthase 1 (CHS1) gene in the teleomorph of Arthroderma benhamiae amplified a fragment from genomic DNA samples of A. benhamiae and the clinical isolate but not from those of A. simii and A. vanbreuseghemii. On the other hand, the species-specific primers of A. simii and A. vanbreuseghemii did not amplify any fragment from the genomic DNA of the clinical isolates. When the isolate was respectively crossed with (+) or (-) tester strains of A. benhamiae, A. simii and A. vanbreuseghemii, ascospores were produced in the crossing with the A. benhamiae (+) strain. Therefore, the isolate was identified to be A. benhamiae (-), confirming the result of molecular analysis. This is the first report on the isolation of A. benhamiae in Japan.