In vitro antifungal activity of micafungin and caspofungin against dermatophytes isolated from China.

Aims: The aims of this study are to investigate the in vitro activities of micafungin and caspofungin that are two new echinocandin antifungal drugs against clinically isolated dermatophytes in China and to define MEC (minimal effective concentration) as the reading endpoints of this study in accordance with (Clinical and laboratory Standards Institute) CLSI M38-A2 reference.

Methods: Minimal effective concentrations (MECs) of micafungin and caspofungin for 82 dermatophyte strains were determined according to CLSI (formerly NCCLS) M38-A2 broth microdilution methods.

Results: (1) The MEC(90s) of micafungin for Trichophyton violaceum and Trichophyton tonsurans were 0.25 μg/mL, and for Microsporum canis and Trichophyton verrucosum were 0.06 μg/mL. The MEC(90s) for Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum gypseum and Epidermophyton floccosum were 0.03 μg/mL. (2) The MEC(90s) of caspofungin for T. rubrum, T. violaceum and T. tonsurans were 1 μg/mL, and for T. mentagrophytes, M. canis, M. gypseum, E. floccosum and T. verrucosum were 0.5 μg/mL. (3) Compared with caspofungin, micafungin demonstrated lower MEC value to dermatophytes (P < 0.05).

Conclusions: Micafungin has stronger in vitro antifungal activity than caspofungin.