Linezolid twice-daily 0.5-h infusion of 200 or 600 mg over 48 h against E. faecalis ATCC 29212. Shown are the pharmacokinetic and pharmacodynamic effects of linezolid on E. faecalis ATCC 29212 during the simulation of twice-daily 0.5-h infusion of 200 mg (A1) and 600 mg (B1) over 48 h in the in vitro PK-PD model (mean; n = 2). ⧫, PCp concentration-time curve; ▴, control growth curve; ▪, killing and regrowth curve. (A2 and B2) Emergence of linezolid-resistant mutants of E. faecalis ATCC 29212 during the corresponding simulations (mean percentage of viable counts; n = 2). Blue, control; green, resistant to 1.0 μg/ml; yellow, resistant to 2.0 μg/ml.