Molecular Epidemiological Analysis of the Spreading Conditions of Trichophyton in Long-Term Care Facilities in Japan

Tinea pedis and tinea unguium are common infectious diseases, and many elderly people are reported to contract these infections. In this study, to investigate whether strains of the same origin are spreading inside a long-term care facility, we analyzed Trichophyton rubrum and Trichophyton mentagrophytes, isolated from the residents and staff at the facilities located in the Kanto area, using a genomic analytical method targeting tandem repeat regions in the nontranscribed spacer (NTS) region of ribosomal DNA. Five NTS types were confirmed in T. rubrum. T. rubrum of various types (types 1 to 5) was detected at each facility, but there was no isolate specific to one facility only. Eight NTS types of T. mentagrophytes were detected, and T. mentagrophytes that carried an NTS type that was confirmed at one facility only (types C4II, F4II, and D4II) was isolated. These T. mentagrophytes sequence types were isolated from several subjects residing at the same facility. This study proved that a T. mentagrophytes strain of the same type had spread in long-term care facilities. We believe in the importance of cleaning at a long-term care facility as a countermeasure to the spread of Trichophyton species.