Identification and subtyping of Trichophyton mentagrophytes by random amplified polymorphic DNA

Trichophyton mentagrophytes is one of the most common pathogens for human and animal dermatophytoses and known as a complex species with variable morphology, and ecologic and genetic backgrounds. We performed random amplified polymorphic DNA (RAPD) analysis on 43 human and 18 animal isolates of T. mentagrophytes along with other 10 anamorphic species of dermatophytes and three teleomorphic species of T. mentagrophytes. Using RAPD analysis with primer 5'-ATGGATC(G,C)(G,C)C-3' (ATGS), all T. mentagrophytes strains produced identical band patterns with those of Arthroderma vanbreuseghemii, one of the teleomorphs of T. mentagrophytes, regardless of their phenotypes. Therefore, T. mentagrophytes could be identified by RAPD analysis with primer ATGS. Using RAPD analysis with primer 5'-ATGGATCGGC-3' (ATG) on T. mentagrophytes, human isolates yielded two distinct subgroups related by their colony morphologies at the time of primary isolation from patients. Three morphologic types--cottony, powdery and persicolor--revealed identical bands whereas the granular type lacked one minor band (0.74 kbp). Animal isolates of T. mentagrophytes produced five band patterns and some of them were identical with those of human isolates. With primer 5'-GAAGGCTCCC-3' (OPAO-15), animal isolates of T. mentagrophytes showed diverse band patterns in contrast to the uniform band pattern of human isolates. These results suggest that RAPD analysis may be a useful tool to identify and subtype T. mentagrophytes complex.