The place of molecular methods in the identification of dermatophytes and the determination of their feasibility

Background and Design: Unlike opportunistic fungi, dermatophytes cannot be isolated on the conventional culture media in a few days. Their growing periods cover approximately two weeks in a suitable media and identification are made with conventional methods as typical macroscopic and microscopic appearance. However, successful results are not always obtained with the phenotypic features, and thus, diagnostic problems and delay in diagnosis and treatment may arise. For this reason, the methods based on nucleic acid amplification have been necessary. In this study, we aimed to identify 56 dermatophytes strains, which were identified by conventional methods, by molecular methods and to investigate the correlation between the two methods and to determine the usability of molecular methods in routine laboratories. Materials and Methods: Several clinical samples of 270 patients with suspected dermatophytoses (hair+scalp, skin and nail scrapings) were examined by conventional methods; Sabouraud dextrose agar, corn meal agar and potato dextrose agar were used for isolation. In case of necessity to hydrolyze urea, to be used different vitamins in Trichophyton agar media were investigated. Polymerase chain reaction (PCR) and sequence analyses were done for the molecular diagnosis. Results: Using conventional methods, 37 strains (66,1%) were identified as Trichophyton(T) rubrum, four (7.1%) - T.mentagrophytes, four (7.1%) - T.tonsurans, one (1.8%) - T.violaceum, eight (14.3%) - Trichophyton spp., one (1.8%) - Microsporum(M) canis, and one (1.8%) - Microsporum spp. According to the molecular and sequence analyses results (T1PCR, 25GAPCR, ITSPCR-RFLP and sequence analyses), 41 (73.8%) strains were identified as T.rubrum, 10 (17.8%) - T.interdigitale, one (1.8%) - T. violaceum, two (3.6%) - M. canis, one (1.8%) - Peacilomyces lilacinus, and one (1,8%) - Aspergillus fumigatus. Discussion: This study suggests that, molecular methods offer fast and reliable results in identification of dermatophytes.