Identification of dermatophytes by AP-PCR

Introduction and Objectives: Dermatophytes are closely related keratinophilic fungi that invade the keratinized tissues in humans causing dermatophytosis. Identification of dermatophytes with conventional methods is time consuming and sometimes problematic because of similarities and variability of species. Genetic amplification has made rapid and perfect identification of dermatophytes possible. The aim of this research is evaluation of AP-PCR method for identification of dermatophytes and to find a suitable approach for a rapid distinguish of dermatophytes. Materials and Methods: Fifty-two isolates from 10 species of dermatophytes include: T. mentagrophytes (10), T. verrucosum (9), T. rubrum (5), T. tonsurans (3), T, violaceum (2), T. schoenleinii (1), M. gypseum (8), M. canis (4), M. ferrugineum (2), E. floccosum (8) were collected and confirmed with microscopic, macroscopic and biochemical tests. Molecular identification was done using AP-PCR (arbitrarily primed PCR) with random primers OPAA11, OPU15, OPAA17 and OPD18. These primers amplified bands of different sizes in species of dermatophytes DNA. Results: All species of dermatophytes were recognized with a distinct DNA band patterns on gel agarose. The best random primer identified for each dermatophyte. The range of obtained bands was between 250 to 2000 bp for all dermatophyte. The best primers for recognizing species were OPAA11 and OPAA17. When OPD18 and OPU15 primers were used more bands observed than OPAA11 and OPPA17 primers. Conclusion: In laboratory, it is always difficult to distinguish T. mentagrophytes from T. rubrum but using this method, the distinction of the two species of fungus can easily done. AP-PCR of dermatophytes with random use of the following primers OPAA11, OPU15, OPAA17 and OPD18 is a useful and rapid method for distinguishing dermatophytes.

Dermatophyte, Random primer, AP-PCR