FIG. 4.

AZM-mediated killing of stationary-phase cells is enhanced by rhamnolipids. (A) Strains were grown to stationary phase in LB medium, as described in the legend to Fig. 3, and exposed to AZM at the indicated concentrations for 22 h. Viable counts were determined by serial dilutions and plating on LB agar plates. (B) Growth curves in LB medium of an rhlA mutant harboring the vector pAK1900 (strain PT1332) or rhlAB-encoding plasmid pAKRHL (strain PT1323). (C) The killing by AZM was assessed after 22 h incubation by determination of viable counts, as described above for panel A. The results are expressed as the means ± standard deviations of three independent experiments.