FIG 1.

Schematics of the experimental evolution strategies of fluconazole resistance in C. auris. (A) Eight independent samples (containing 4 × 10⁵ cells) of C. auris BJCA001 were initially cultured in 0.2 ml RPMI 1640 medium (OD₆₀₀ ≈ 0.1) containing 32 mg/liter fluconazole (FLC) and grown at 35°C for 48 h. After two more passages under the same conditions, cells were inoculated and grown in YPD medium containing 64 mg/liter and then 128 mg/liter fluconazole for three passages each. Two and three samples failed to grow after treated with 32 mg/liter and 64 mg/liter fluconazole, respectively. Three isolates that grew in the medium containing 128 mg/liter fluconazole were then plated on YPD medium for 3 days of incubation at 37°C. Eighteen independent colonies (A1 to A18) with MICs of ≥32 mg/liter were picked and subjected to whole-genome sequencing (WGS). To strengthen the fluconazole-resistant feature, samples A1 to A8 were inoculated into RPMI 1640 medium containing 128 mg/liter fluconazole for four additional passages and then subjected to WGS (samples B1 to B8). (B) Induction of the loss of fluconazole resistance strain B1. Cells of the fluconazole-resistant strain B1 were inoculated and grown on YPD plates without fluconazole at 25°C for 1 month. Colonies were then subjected to MIC testing. (C) MICs of fluconazole for BJCA001 and strains A1 to A18, B1 to B8, and R1 to R3.