Fig 3.

Increased antibiotic resistance in hypoxia is reversed by a multidrug efflux pump inhibitor. MICs for ATCC 27853 were determined by broth microdilution using a Sensititre GNX2F susceptibility plate under normoxia (N), hypoxia (H), or hypoxia in the presence of the efflux pump inhibitor (H+EPI) Phe-Arg β-naphthylamide dihydrochloride (20 μg/ml). A selection of CF-relevant antibiotics for which the EPI decreased the MIC under hypoxia is shown. Values are means ± standard errors of the means for 3 independent experiments (*, P < 0.05).