Molecular epidemiology of Microsporum canis isolated from Japanese cats, dogs and pet owners by multilocus microsatellite typing fragment analysis.

Multilocus microsatellite typing (MLMT) was performed on 93 strains of Microsporum canis isolated between 2012 and 2017 from 75 cats, eight dogs and 10 pet owners. These strains were derived from two major reservoirs: commercial breeding facilities and pet shops (PS), and stray cats and pet cats that went outdoors and came in contact with stray cats (Outdoor). Six microsatellite markers were used for genotyping. These 93 strains included 22 genotypes, 11 previously detected in Japan and 11 new genotypes. Strains belonging to the previously reported genotypes P and A were distributed widely throughout Japan. Genotype P was the most frequent, accounting for 37 (39.8%) of the 93 strains, most derived from Outdoor sources. Genotype A was the second most frequent, being present in 11 (11.8%) of the 93 strains, most derived from the PS reservoir. All new genotypes were detected in isolates from cats, with many of these derived from the Outdoor reservoir. The consistency of infection was shown in 18 of 19 familial cases. These findings indicate that genotypes differ in strains derived from PS and Outdoor reservoirs and that genotyping by MLMT is useful for tracking the routes of spread and transmission of M. canis in Japan.