FIG 2.

Results of in vitro competition experiments of PAOΔcreBC versus PAO1 (A) and PAOΔcreD versus PAO1 (B) in the presence of β-lactams. In vitro competitions were performed using LB broth flasks containing 1/4, 1/2, and 3/4 MICs of ceftazidime (CAZ) (0.25, 0.5, and 0.75 μg/ml, respectively), imipenem (IMP) (0.25, 0.5, and 0.75 μg/ml, respectively), or cefoxitin (FOX) (250, 500, and 750 μg/ml, respectively). The CI values obtained for each of the eight independent experiments are plotted, and the median values are shown in parentheses. P values of <0.05 for the comparison of the CIs in the presence and absence of antibiotics are indicated with an asterisk.