In vitro antifungal susceptibility testing.

All 14 isolates of the three species were tested for in vitro susceptibility against currently available systemic antifungals (18) and olorofim by using the Clinical and Laboratory Standards Institute (CLSI) M38-ED3:2017 reference method for broth dilution antifungal susceptibility testing of filamentous fungi (42). Olorofim was provided by F2G, Ltd., and all other drugs were purchased from Sigma (St. Louis, MO). The MIC was defined as the lowest concentration that completely inhibited growth in comparison to the growth in the drug-free well (control) as assessed by visual inspection. All incubations were performed in three biological replicates on different days, and MICs were read after incubation for 48 h at 35 to 37°C.