FIG.2.
Competition assays with E. coli strains TEM-1 and TEM-12 exposed to cefotaxime in the in vitro kinetic model. Five selective windows were investigated: 1 h (A), 2 h (B), 4 h (C), 8 h (D), and 12 h (E). In the first series (low Cmax; left panels) T > MIC was varied for TEM-1 (3, 4, 6, 10, and 14 h), and fixed (2 h) for TEM-12. Each graph displays means of 5 experiments with the exception of SW 2 h, which shows means based on 10 experiments. The bars represent standard deviations. In the second series of SWs (high Cmax; right panels) the cefotaxime doses were four times higher to prevent the emergence of high-level resistant mutants. T > MIC was varied for strain TEM-1 (4, 5, 7, 11, and 15 h), and fixed (3 h) for strain TEM-12. Each graph displays the means of two experiments. Solid line, strain TEM-12; dashed line, strain TEM-1.