Molecular Identification of Candida Species Isolated from Onychomycosis in Shanghai, China

Candida is a common cause of onychomycosis, especially for fingernail onychomycosis. In this study, two simple PCR-based assays combined with the internal transcribed spacers sequencing were performed to reveal the prevalence of Candida species including emerging species in onychomycosis, and triazole antifungal susceptibility profiles for Candida species were also evaluated. Among 210 Candida strains isolated from onychomycosis, Candida parapsilosis was the most common species (54.3%), followed by C. albicans (23.3%) and C. metapsilosis (9.5%). However, C. metapsilosis became the second leading species in toenail onychomycosis and accounted for 19.5% of Candida isolates from toenail samples. C. nivariensis, an emerging species, was firstly recovered from a toenail sample. Other emerging species such as C. orthopsilosis, C. pararugosa and C. fabryi were also identified by molecular tools. C. metapsilosis isolates exhibited significantly higher fluconazole minimum inhibitory concentrations than those exhibited by C. parapsilosis and C. albicans (P < 0.001). This study provides insight into the prevalence, distribution and susceptibility profiles of Candida species including emerging Candida species in onychomycosis.