The Present State of Trichophyton tonsurans Infection in Japan and Measures to Combat It

Scalp microbiota in members of a Japanese high school judo team including Trichophyton tonsurans carriers

Trichophyton tonsurans is a major causative fungus of human dermatophytosis, which has been isolated from contact sport players in Japan. The microbiome in the scalp of judoists with or without T. tonsurans infection was analyzed to investigate the correlation between T. tonsurans infection and microbiome profile. Among 30 members of the same judo team in a high school, samples were collected by scrubbing their scalp with shampoo hairbrushes; then, DNA was extracted directly from the obtained scales. Twenty-seven datasets were subjects for microbiome analysis and T. tonsurans was detected in six members (no T. tonsurans-positive participants had scalp lesions). Regarding the fungal microbiome, Cyphellophora were more abundant in the T. tonsurans-positive group (TP) than T. tonsurans-negative group (TN) (P < 0.05). Regarding the Malassezia microbiome, Malassezia caprae were more abundant in TP than TN (P < 0.01). Regarding the bacterial microbiome, Lactococcus, Actinobacillus, Beijerinckiaceae and Xanthomonas were more abundant in TP than TN (P < 0.05). Also, the Shannon diversity index revealed no significant diversity between TP and TN, and 3-D principal coordinate analysis revealed no clear separation between TP and TN. There was practically no difference in microbiome between TP and TN, indicating that T. tonsurans could colonize humans regardless of their original microbiome. T. tonsurans coexisted with other fungi and bacteria without affecting species diversity in asymptomatic carriers. To our knowledge, this is the first investigation of the correlation between T. tonsurans infection and microbiome profile.