Fluconazole susceptibility testing. The inhibition on growth by fluconazole was determined by microdilution method. The wild-type strain (SC5314, squares) and the cdr1/cdr1 mutant cells (DSY448, triangles) were grown in the absence (solid symbols) or presence of 10% fetal bovine serum (open symbols). The optical density (OD) of each well was read at 600 nm after incubated at 35°C for 48 hours. The horizontal dotted line represents 50% inhibition and the vertical dotted line refers the inhibition by 0.125 mg/l fluconazole.