Molecular Epidemiology of Trichophyton tonsurans, the Causative Dermatophyte of the Tinea Gladiatorum Epidemic in Japan between 2011 and 2015

Trichophyton tonsurans, a major pathogen causing tinea capitis and tinea corporis, has been isolated from contact sports-players in Japan. The molecular types of 208 strains isolated between 2011 and 2015 were determined to understand the contemporary Japanese epidemic. Of these, 142 were isolated from practitioners of judo, 28 from wrestlers, 7 from sumo wrestlers, and 31 from individuals with unknown backgrounds. Based on length polymorphisms of the non-transcribed spacer (NTS) region of the ribosomal RNA gene, these 208 strains were divided into 3 subtypes: NTS I (204; 98.1%), II (3; 1.4%), and III (1; 0.5%). Single nucleotide polymorphisms (SNPs) and deletion/insertion profiles in the NTS region, length polymorphisms of the alkaline protease 1 gene, and a SNP in the carboxypeptidase Y gene were identified in 50 NTS I strains isolated between 2011 and 2015, and in 10 strains isolated before 2005. All 60 strains were classified as the same molecular type, with a profile identical to that of type Ib, a major type in the United States of America. These results indicate that NTS I strains isolated in Japan are clonal and independent of the type of sports activity.