Figure 4. Effect of the PMF on the antimicrobial activity of imipenem.
Effect of 50 µM CCCP or 25 µM valinomycin on the anti-Burkholderia activity of 12.5 µg/ml imipenem (IM) (A). Stationary phase B. pseudomallei controls grown overnight in LBG broth were treated with 0.25% DMSO for 2.5 h. Killing of S. Typhimurium (STM) and E. coli (Eco) grown to log phase in LBG broth (B, C, D) or EG medium (E, F) by IM. Selected samples were treated with 750 µM spermine NONOate (sNO) or 50 µM CCCP. The samples in F were treated with 10 µM CCCP ± 250 µM sNO. p<0.01 compared to the CCCP, valinomycin- or sNO-treated groups. The PMF was estimated by measuring the accumulation of DiSC3(5) in STM (G). The data are expressed as arbitrary fluorescent units (A.U.). p<0.001 compared to the sNO-treated EG group. The data are the mean ± SEM from 3–5 independent observations collected on 2 separate days.