Morphological and molecular differentiation by high resolution melting curves (hrma) and sequencing of the trichophyton mentagrophytes complex in human strains in valparaiso, chile

Trichophyton mentagrophytes complex is the most frequent agent found in dermatophyte isolates after Trichophyton rubrum. It is divided into 3 main groups: (1) Trichophyton benhamiae and related species; (2) Trichophyton simii and 2 related species, Trichophyton quinckeanum and Trichophyton schoenleinii; and (3) T. mentagrophytes, T. interdigitale, and related species. They are all difficult to identify by morphophysiology. With the aim of classifying them at the species level, a descriptive study was performed on 17 isolated clinical strains identified in the Mycology Laboratory of the Universidad de Valparaíso as belonging to the T. mentagrophytes complex. They were compared with 3 reference strains (T. mentagrophytes CBS 318.56, T. interdigitale CBS 428.63, Trichophyton erinacei CBS 511.73). Morphophysiological and molecular tests were performed by high resolution melting analysis curves and ITS regions sequencing. Phenotypically, 3 species of the complex were identified. Molecular analyses reclassified all the species as belonging to T. interdigitale. In conclusion, no reliable morphophysiological patterns were established to differentiate between the species of the complex. Molecularly, all the strains studied were classified as T. interdigitale.