Comparison of in vitro activities of newer triazoles and classic antifungal agents against dermatophyte species isolated from Iranian University Hospitals: a multi-central study

BACKGROUND: Dermatophytes have the ability to invade the keratin layer of humans and cause infections. The aims of this study were the accurate identification of dermatophytes by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism method and sequencing and comparison between the in vitro activities of newer and established antifungal agents against them. METHODS: Clinical specimens of patients from five Iranian university laboratories were entered in this study. Samples were cultured on sabouraud dextrose agar medium. For molecular identification, extracted DNAs were amplified by the universal fungal primers ITS1 and ITS4, and digested with MvaI enzymes. The antifungal susceptibility test for each isolate to terbinafine, griseofulvin, caspofungin, fluconazole, itraconazole, luliconazole, and isavuconazole was performed, according to the microdilution CLSI M38-A2 and CLSI M61 standard methods. RESULTS: Two hundred and seven fungi species similar to dermatophytes were isolated of which 198 (95.6%) were dermatophytes by molecular assay. The most commonly isolated were Trichophyton mentagrophytes (76/198), followed by Trichophyton interdigitale (57/198), Trichophyton rubrum (34/198), Trichophyton tonsurans (12/198), Microsporum canis (10/198), Trichophyton simii (3/198), Epidermophyton floccosum (3/198), Trichophyton violaceum (2/198), and Trichophyton benhamiae (1/198). The GM MIC and MIC(90) values for all the isolates were as follows: terbinafine (0.091 and 1 μg/ml), griseofulvin (1.01 and 4 μg/ml), caspofungin (0.06 and 4 μg/ml), fluconazole (16.52 and 32 μg/ml), itraconazole (0.861 and 8 μg/ml), isavuconazole (0.074 and 2 μg/ml), and luliconazole (0.018 and 0.25 μg/ml). CONCLUSION: Trichophyton mentagrophytes, Trichophyton interdigitale, and Trichophyton rubrum were the most common fungal species isolated from the patients. luliconazole, terbinafine, and isavuconazole in vitro were revealed to be the most effective antifungal agents against all dermatophyte isolates.