Fig 6.

Expression of brlR partially restores resistance in the absence of MexAB-OprM and MexEF-OprN. P. aeruginosa PAO1, PAO255, and PAO255 biofilms overexpressing brlR (PAO255/pJN-brlR) were grown for 1 day and subsequently treated for 1 h with tobramycin (50 μg/ml) (A), kanamycin (150 μg/ml) (B), trimethoprim (150 μg/ml) and tetracycline (100 μg/ml) (C), and norfloxacin (400 μg/ml) (D). Experiments were carried out at least five times. Error bars denote standard deviations. * and **, significantly different from the values for P. aeruginosa PAO1 (P ≤ 0.05 and P ≤ 0.01, respectively).