Fig. 5: Role of total protein and 16s rRNA in nalidixic acid and tetracycline combination.

a Mean total protein per cell in the presence of different antibiotics. Mean total protein per cell increases in the presence of nalidixic acid but not in the presence of tetracycline. All antibiotic concentrations were used at 0.75× MIC. Data represent mean and SD from three independent experiments. All values represent **p < 0.01; one-way ANOVA followed by the Kruskal–Wallis post test was applied. b Expression of 16s rRNA gene in the presence of various antibiotics normalized to no drug control. Relative expression of 16s rRNA gene increases in the presence of nalidixic acid but not in the presence of tetracycline. The combination of both antibiotics leads to an intermediate increase in expression. There is a remarkable difference in 16s rRNA gene expression between nalidixic acid-resistant (A. baumannii AYE and E. coli RPTU54) and -susceptible bacteria (E. coli MG1655). All antibiotic concentrations were used at 0.75× MIC. Data represent mean and SD from three independent experiments. All values represent **p < 0.01; one-way ANOVA followed by the Kruskal–Wallis post test was applied.