Fig. 1.

Effect of antibiotics on biofilm formation and motility of P. aeruginosa. (a) The effects of different concentrations of antibiotics (tobramycin, Left; tetracycline, Center; ciprofloxacin; Right) on the formation of static biofilms was measured as described in ref. 33. Red, planktonic growth; black, growth-forming biofilm. The mean value and standard deviations of eight different replicates are shown. Standard deviation bar is not shown when its size was lower than the size of the symbol in the graph. The arrows indicate the concentrations of antibiotics used for the experiments with microarrays. (b) Effect of antibiotics in P. aeruginosa motility. Swarming (Upper) and swimming (Lower) motility was measured as described in ref. 34. Growth culture media were different as the one used in the biofilm assay and the experiments with microarrays, and thus antibiotic concentrations also were different. The concentrations used were 0.015 mg/liter ciprofloxacin, 0.5 mg/liter tetracycline, and 0.25 mg/liter tobramycin.