Species and drug susceptibility of common dermatophytes in Xinjiang

To evaluate the in vitro antifungal susceptibility of dermatophytes to nine antifungal agents, 153 dermatophyte strains deposited in the Dermatological and Mycological Laboratory of the First Affiliated Hospital of Xinjiang Medical University between 2010 and 2023 were identified by using morphological and molecular biological methods. The minimum inhibitory concentration (MIC) values of terbinafine, amorolfine, luliconazole, amphotericin B, ciclopirox, itraconazole, voriconazole, griseofulvin, and fluconazole were determined by the microdilution method. Nine species of dermatophytes were identified, including 59 strains of Trichophyton rubrum (39%), 17 strains of T. interdigitale (11%), 15 strains of T. mentagrophytes (10%), 9 strains of T. tonsurans (6%), 8 strains of T. verrucosum (5%), 9 strains of T. violaceum (6%), 3 strains of T. schoenleinii (2%), 19 strains of Microsporum canis (12%), and 14 strains of M. ferrugineum (9%). In vitro susceptibility test revealed that luliconazole exhibited the strongest antifungal activity, with MIC values ranging from 0.000 5 to 0.004 μg/mL. Terbinafine (MIC: 0.000 125-0.25 μg/mL) itraconazole (MIC: 0.004-1 μg/mL), voriconazole (MIC: 0.004-0.5 μg/mL), amorolfine (MIC: 0.004-1 μg/mL), and ciclopirox (MIC: 0.063-4 μg/mL) also showed potent activity. Griseofulvin (MIC: 0.016-32 μg/mL) and amphotericin B (MIC: 0.032-16 μg/mL) displayed relatively weak antifungal effects. Fluconazole showed the poorest activity, with MIC values ranging from 0.125 to 64 μg/mL; notably, two strains of Microsporum ferrugineum and one strain of Trichophyton violaceum exhibited fluconazole MICs >64 μg/mL. Among all tested antifungal agents, luliconazole and terbinafine demonstrated the strongest in vitro activity against dermatophytes, whereas fluconazole and amphotericin B showed the weakest efficacy, with the emergence of resistant isolates.