Fig 2. Fleroxacin accumulation in E. aerogenes strains.

Strains were grown in LB broth and cells were harvested at mid-log phase. Cells were washed and concentrated 10-fold in NaPi pH 7.0 supplemented with Mg²⁺. Fleroxacin (FLX) was added to the bacterial suspensions in the absence or in the presence of 10 μM CCCP. After a 30 min incubation time, bacterial lysates were prepared as described in Materials and Methods. The concentration of FLX in the lysates was estimated after normalization of the spectra to their corresponding tryptophan emission peak at 356 nm. The antibiotic-free control time-zero was subtracted from the values obtained for each assay. All values are means of at least three independent experiments.