TolB is crucial for <i>P. aeruginosa</i> resistance and persistence.

<p>(A) Growth of PAO1 (circles) and PAO1 <i>tolB</i> conditional mutant (diamonds) at 37°C in MH broth at 200 rpm in flasks after two successive subcultures in the presence (filled symbols) or in the absence (open symbols) of 0.2% arabinose. The graph is representative of several assays giving similar results. (B) Lytic effect of SDS (0–5%), measured as decrease in cell suspension turbidity (OD₆₀₀), on PAO1 wild-type cells (WT, filled circles), TolB-deficient mutant cells (<i>tolB</i>, open diamonds) and TolB-proficient mutant cells (<i>tolB</i> TolB⁺, filled diamonds). (C) Resistance of WT, <i>tolB</i> and <i>tolB</i> TolB⁺ to the bactericidal activity of 50% human serum or (D) to the bactericidal antibiotic ofloxacin (0.5 mg/L), expressed as percent survival compared to untreated cells. Results in panels B–D are the mean (± SD) of four independent experiments. (E) Persistence of WT, <i>tolB</i> and <i>tolB</i> TolB⁺ cells in <i>G. mellonella</i> larvae at 2 h post-infection. Sixteen larvae per group were infected in three independent assays. ***, P<0.001 (one-way ANOVA).