Killing kinetics for PAO1 (dashed lines and open symbols) and PAOΔmutS (solid lines and solid symbols). (A) Imipenem killing kinetics. Squares, control with no antibiotic; triangles, imipenem at 4 μg/ml; diamonds, imipenem at 8 μg/ml. (B) Ciprofloxacin killing kinetics. Squares, control with no antibiotic; triangles, ciprofloxacin at 0.5 μg/ml; diamonds; ciprofloxacin at 1 μg/ml.