Molecular Epidemiology of Japanese Isolates of Microsporum canis Based on Multilocus Microsatellite Typing Fragment Analysis.

Intraspecies polymorphisms of Microsporum canis strains isolated from human lesions and domesticated cats in Japan were examined by multilocus microsatellite (MS) analysis. Using 9 MS markers, 70 strains were classified into 20 genotypes (genotypes A to T). Of the 9 MS markers used, 5 were considered useful for genotyping, whereas the other 4 were not. The combination of MS2, MS4, and MS7 had the highest resolution power for inter-strain differentiation. Genotype A, present in 15 strains (21.4%), was the most frequent, followed by genotypes H (10 strains, 14.3%), P (8 strains, 11.4%), I (6 strains, 8.6%), and S (6 strains, 8.6%). Eight individual genotypes were present in one strain each. Five episodes of infection of humans and cats living in the same household were analyzed, with strains in all 5 respective households showing the same genotypes. Analysis of geographical distribution established that both genotypes A and H were isolated from 6 prefectures of Honshu and Kyushu islands. To our knowledge, this is the first report showing intraspecies polymorphisms of M. canis isolated in Japan using molecular methods.