Determination of genetic diversity and susceptibility of Trichophyton mentagrophytes isolates against antifungal effects of ethanolic extract of Allium jesdianum

Dermatophytes are a group of fungi with keratinophilic properties. They are able to invade epidermis, especially stratum corneum, by production of proteolytic enzymes such as keratinase. Trichophyton mentagrophytes (T. mentagrophytes) is a common cosmopolitan dermatophyte species. This species has different varieties based on genetic characteristics. In this study genetic diversity of 20 clinical isolates of T. mentagrophytes and their susceptibility to ethanolic extract of Allium jesdianum (A. jesdianum) were evaluated. Genetic diversity of the isolates was assessed by Random Amplified Polymorphic DNA (RAPD) method using 4 primers including OPN16, A08, OPD18 and R28. Then, susceptibility of T. mentagrophytes isolates to A. jesdianum extract was determined by standard microdilution broth method. The MIC values of the isolates were between 6.1 and 49.3 mg/ml (mean MIC: 20.3 mg/ml), whereas the MFC values of the isolates were between 24.6 and 49.3 mg/ml (mean MFC: 40.6 mg/ml). Twenty eight propagated DNA fragments were achieved in RAPD-PCR reaction. The most propagated DNA fragments (9 bands) were related to OPD18 primer. The R28 primer showed the least propagated DNA fragments (5 bands). Drawn dendrogram identified 3 main groups among 20 T. mentagrophytes isolates according to the all primers in 65% genetic distance. Most of T. mentagrophytes isolates (75%) were placed in group 2 and 100% genetical similarity was only seen between 2 isolates. It was concluded that all T. mentagrophytes genotypes were susceptible to A. jesdianum. The correlation between antifungal susceptibility and T. mentagrophytes genotype may be of potential therapeutic significance and larger studies are needed to prove this finding.