Fig. 7: cdrA promoter activity increases following treatment with sub-MIC thiostrepton and tobramycin.

PAO1 or oprF::FRT cells containing pMS402(Empty) or pMS402(PcdrA) were treated with ½ MIC cefixime (a), thiostrepton (b), tobramycin (c) or a vehicle control and monitored for growth and luminescence. Mean relative luminescence (RLU = arbitrary luminescence values divided by OD₆₀₀) of the treated wells divided by the mean RLU of the matched untreated wells is plotted on the Y-axis as the fold change. The time in hours is plotted on the X-axis and readings were taken every 15 min. Circles represent the mean of six values taken across three biological replicates each performed in technical duplicate. Error bars represent the standard error of the mean. Red and blue circles represent data from PAO1 and oprF::FRT containing pMS402(PcdrA), respectively. Data are plotted as a fold change over the empty vector control, therefore the empty vector data are all equal to one, as they would be a well’s fold change versus itself. A two-way ANOVA followed by Dunnett’s multiple comparisons test was performed to compare each antibiotic treatment condition across the time course to the six-hour time point, and the results of the comparison are shown for the 16-h time point. ns not significant, ****p < 0.0001. Source data are provided in Supplementary Data Set 1.