Mycological aspects of onychomycosis in Khuzestan Province, Iran: A shift from dermatophytes towards yeasts

Background and Purpose: Onychomycosis is fungal infection of the nails with an overall increasing incidence, worldwide. The epidemiological aspects of onychomycosis in Khuzestan, Iran, have not been established. In this study, we aimed to evaluate the clinical and mycological status of fungal nail infection in Khuzestan Province, Iran. Materials and Methods: The study population included 433 patients (143 males vs. 290 females). Nail samples underwent primary direct microscopy and culture. The isolated yeasts and dermatophytes were then subjected to additional molecular identification by r-DNA ITS-RFLP. Identification of some non-dermatophytic molds (NDMs) and unknown yeasts was accomplished by ITS and beta-tubulin sequencing. Results: Onychomycosis was confirmed in 154 patients (males: 36.4%; n=56 vs. females: 63.6%; n=98), whose age ranged from 2 to 85 years, with the highest prevalence in the age group of 41-50 years. Infection mostly occurred due to yeasts (57.15%), with Candida albicans as the most frequent (29.35%) species, followed by C. parapsilosis (13.8%) and C. tropicalis (4.5%). Dermatophytes were isolated in 38.35% of the cases; the most common isolates were found to be Trichophyton interdigitale (21.1%), Epidermophyton floccosum (10.5%), T. rubrum (5.25%), and Microsporum canis (1.5%). NDMs were isolated from 4.5% of the cases with Aspergillus spp. as the most common agent. Dermatophytes and NDMs were more frequently seen in toenails, whereas yeasts mostly infected fingernails. Fingernail onychomycosis was significantly more prevalent among females than in males (P<0.05). Conclusion: The study highlights that in Khuzestan province, the causative agents of onychomycosis have shifted from dermatophytes to yeasts.