Trichophyton mentagrophytes and T interdigitale genotypes are associated with particular geographic areas and clinical manifestations

The fungi Trichophyton mentagrophytes and T interdigitale account for significant amount of dermatophytosis cases worldwide. These two dermatophytes form a species complex and have a number of ribosomal internal transcribed spacer (ITS) region genotypes, allowing simultaneous species identification and strain typing. Our aim was to describe the geographic distribution of T mentagrophytes/T interdigitale ITS region genotypes and find an association between the genotypes and clinical presentations of respective infections. We performed rDNA ITS region sequencing in 397 Iranian T mentagrophytes/T interdigitale isolates and analysed all available in GenBank entries with sequences of this kind. For the study, 515 clinical annotations were available. Statistical analysis was performed by chi-squared test and Spearman rank correlation analysis. A total of 971 sequences belonged to genotypes with at least 10 geographic annotations and were classified on the basis of exclusive occurrence in a particular region or high relative contribution to a regional sample. We discerned Asian and Oceanian ( Type V, Type VIII, ), European ( Type III, Type III*, Type VI) and cosmopolitan ( Type I, Type II, Type II* and Type XXIV) genotypes. There was statistically significant difference in the ITS genotype distribution between different affected body sites. Trichophyton mentagrophytes Type VIII correlated with tinea cruris, T mentagrophytes Type V correlated with tinea corporis, T interdigitale Type II correlated with tinea pedis and onychomycosis. Trichophyton mentagrophytes and T interdigitale genotypes can be associated with distinct geographic locations and particular clinical presentations.