FIGURE 5.

Measurement of trans-epithelial resistance (TER), CFU and PFU at 72 h p.i. (A) Only combined phage and ciprofloxacin (CIP) treatment protected epithelial cells from PAO1 infection (violet bars). (B) No viable bacteria (detection limit of 10² CFU/well) were recovered from the apical side of the wild type and CTL cells, while surviving bacteria occurred in 2/3 experiments on the cftr-cells. (C) Phages remained at the level of the inoculum in the absence of bacteria (gray bars) but replicated in the presence of PAO1 treated with phages alone (blue bars). CIP reduced phage replication due to killing of PAO1 host cells. (D) Phages were added at t = 0 h at a 50:50 ratio. With the exception of the wild type cell line (blue bar), this ratio was maintained until 72 h p.i. Values represent mean and SEM (panels A,D), and median and range (panels B,C) of three independently performed experiments. Differences in TER between the conditions were assessed using a one-way ANOVA; *p < 0.05, **p < 0.01, ***p < 0.005.