Molecular Identification of Candida Species Isolated from Onychomycosis with In Vitro Antifungal Susceptibility Profiles

Background: Onychomycosis is one of the most common fungal infections. The most common etiological agents of onychomycosis in Iran are Candida species, especially fingernails. It is more common in women than men, particularly workers in occupations requiring them to submerge their hands or feet in water for prolonged periods. Objectives: The current study's main aim was to determine the abundance of candidal onychomycosis, identify the Candida species using molecular methods, and evaluate the in vitro antifungal susceptibility profiles. Methods: One hundred forty samples were obtained from patients suspected of onychomycosis, and 51 (36.4%) Candida strains were identified by PCR-RFLP. The in vitro susceptibility of four triazole (FLC, ITC, VRC, and POS) antifungal drug testing of 51 Candida species was performed using broth microdilution. Results: Direct microscopic examination by KOH 20% of 140 nail samples showed that 51 (36.4%) samples were positive in terms of fungal elements, with Candida parapsilosis complex being the most frequently isolated of patients, followed by C. albicans complex, C. glabrata, C. krusei, C. tropicalis, C. guilliermondii, C. famata, C. kefyr, and Candida species. All Candida species showed they were susceptible to four triazoles, except that five C. krusei were resistant to fluconazole. Only one C. glabrata isolates and one C. parapsilosis isolate were resistant to fluconazole. Conclusions: The growing trend towards the frequency of fingernail onychomycosis in housewives has been noticeable in the last decades in Iran. Therefore, accurate identification of Candida species and perform in vitro antifungal susceptibility testing can aid physicians in choosing an effective potential drug for treating onychomycosis patients.