Molecular identification and antifungal susceptibility profile of rare and emerging yeast species causing onychomycosis.

Objectives: Onychomycosis is a nail infection caused by various fungal agents. In recent years, there has been an increase in cases of onychomycosis caused by rare fungi, which are often challenging to identify using conventional methods. Sometimes, these unusual species exhibit different antifungal susceptibility patterns compared to more common yeast species. Therefore, this study aimed to identify rare yeast species causing onychomycosis and assess their antifungal susceptibility profiles.

Results: Nineteen rare and emerging yeast isolates, representing seven species, including Candida orthopsilosis (n = 9, 47.36%), Clavispora lusitaniae (formerly Candida lusitaniae) (n = 2, 10.52%), Wickerhamiella pararugosa (formerly Candida pararugosa) (n = 2, 10.52%), Naganishia diffluens (formerly Cryptococcus diffluens) (n = 2, 10.52%), Wickerhamomyces anomalus (n = 2, 10.52%), Cyberlindnera fabianii (n = 1, 5.26%), and Meyerozyma caribbica (formerly Candida fermentati) (n = 1, 5.26%), were identified. Most rare yeast agents exhibited high minimum inhibitory concentration (MIC) values for fluconazole.