Effect of bfmS deletion on bacterial virulence and the ability of P. aeruginosa to adapt to the host.

In all panels, MPAO1 and ΔbfmS harbor plasmid PAK1900, respectively. A) Photographs show lettuce midribs after three days of infection with 1×107 cfu of P. aeruginosa. Wild-type MPAO1 strain or ΔbfmS/p-bfmS strain shows necrosis and tissue maceration of infection. The ΔbfmS strain shows weak signs of infection. B) Constitutive expression of rhlR in ΔbfmS strain could restore the virulence to the level of the wild-type MPAO1 strain. In A) and B), lettuce leaves were inoculated with 10 mM MgSO4 as a control. C) Effect of P. aeruginosa inoculum on the survival rate of murine lung epithelial cell line 12 (MLE-12). D) Internalization of P. aeruginosa into the murine lung epithelial cell line 12 (MLE-12). In C) and D), values represent means ± SEM. E) Recovery of P. aeruginosa derivatives in a mouse model of acute pneumonia. Results are expressed as the ratio of cfu recovered per lung (output) to cfu present in the initial inoculum (input) and represent results from n = 9–10 mice per strain; the line shows the geometric mean for each group. CFU, Colony-Forming Unit. The Mann–Whitney test was used to calculate p-values (two-tailed). * p