Molecular characterization of dermatophytes of the Trichophyton mentagrophytes complex found in Taiwan with emphasis on their correlation with clinical observations

Summary Background  Fungi of the Trichophyton mentagrophytes complex are important pathogenic dermatophytes capable of causing various human skin infections. There are many species and varieties involved in this complex. Due to morphological similarity and existing intermediate forms and variants, unequivocally separating these dermatophytes is not always straightforward, and sampling appropriate isolates for research is often troublesome. Communicating epidemiological statistics of these dermatophytes is greatly impeded because taxonomic schemes adopted by different research groups are inconsistent and hardly comparable. Objectives  To analyse the molecular types existing within isolates of the T. mentagrophytes complex in Taiwan and evaluate the applicability of the current taxonomy on these isolates. Methods  Forty‐eight isolates of the T. mentagrophytes complex were obtained from humans and animals (rabbit, guinea pig and hedgehog) in Taiwan. Sequences of ITS1‐5.8S‐ITS2 and β‐tubulin gene regions of each isolate were used for molecular typing. Results  Among the 48 isolates, 43 belonged to the T. interdigitale clade, including 21 of the anthropophilic strain and 22 of the zoophilic strain, and five belonged to the T. erinacei clade. No isolates of the T. mentagrophytes genotype were found. Conclusions  The isolates previously identified as T. mentagrophytes should be relabelled as T. interdigitale according to current taxonomy. Because the taxonomy is quite different from what it used to be, confusion in the nomenclature of the T. mentagrophytes complex is to be expected. The applicability of the current taxonomic concept may require further evaluation.