Molecular approaches to the study of dermatophytes.

Dermatophyte species are common keratinophilic fungi responsible for superficial infections called dermatophytosis or ringworm and composed of three anamorphic genera, Trichophyton, Microsporum and Epidermophyton. Through the use of several complementary molecular methods, dermatophytes have been shown to constitute an homogeneous group of species with very low genetic diversity contrasting with high phenotypic heterogeneity. For diagnostic applications, distinction among isolates to the species level was easily performed using polymerase chain reaction-based assays, which could be useful tools in the mycology laboratory, particularly for atypical isolates. In contrast, in all but a few cases distinction between dermatophyte strains has failed, which has hindered the development of molecular-based epidemiological investigations.