FIG. 4.

Time course of increase in NPN fluorescence intensity in P. aeruginosa cells treated with permeabilizers. At 0 s, 5 μM NPN was added to intact P. aeruginosa cells. (A) At the arrows, the following agents were added: a, azithromycin (128 μg/ml); b, azithromycin (8 μg/ml); c, clarithromycin (128 μg/ml); d, erythromycin (128 μg/ml). (B) At the arrow, 10 mM EDTA was added. (C) At the arrow, gentamicin (128 μg/ml) was added. (D) At the arrow, ceftazidime (128 μg/ml) was added. The data are representative of three separate experiments.