Abstract: Objective To study Fonsecaea spp. strains isolated from China to understand the characteristics of antifungal drug susceptibility and to provide data basis for the development of precise antifungal drug regimens for dark fungal diseases caused by Fonsecaea spp. infections in China. Methods Using the broth microdilution method (CLSI M38-A2 method) recommended by the American Clinical Laboratory Standardization Committee for filamentous fungi, in this study, in vitro drug sensitivity tests were conducted on 32 clinical isolates of Fonsecaea spp. against 11 clinical antifungal drugs. We also systematically analyzed the drug sensitivity characteristics and clinical prognosis of 83 reported cases of Fonsecaea spp. infection in China and abroad. Results Fonsecaea spp. was most sensitive to the antifungal activity of second-generation azole antifungal drugs, including:posaconazole (MIC₅₀=0.25 μg/mL, MIC₉₀=0.5 μg/mL), esaconazole (MIC₅₀=0.25 μg/mL, MIC₉₀=0.5 μg/mL), voriconazole (MIC₅₀=0.125 μg/mL, MIC₉₀=0.25 μg/mL). While amphotericin B (MIC₅₀=4 μg/mL, MIC₉₀=8 μg/mL), fluconazole (MIC₅₀=8 μg/mL, MIC₉₀>8 μg/mL), and echinocandins (MEC₅₀=8 μg/mL, MEC₉₀>8 μg/mL) had lower antifungal activity against Fonsecaea spp. Conclusion For the antifungal treatment of Fonsecaea spp. infection, it is advisable to give preference to second-generation azoles (posaconazole, esaconazole, voriconazole, etc.). The in vitro combined drug sensitivity profile of clinical isolates of Fonsecaea spp. warrants further study.

Key words: dark fungal disease, Fonsecaea spp., in vitro drug sensitivity test, antifungal drugs