Fig. 4.

Virulence factor production affects bacterial uptake and host colonization ability. a Bacterial load inside C. elegans guts measured immediately after the recovery of worms from the exposure plates (0 h post exposure; hpe). Comparisons across isogenic PAO1 mutant strains, each deficient for the production of one or two virulence factors, reveal that the two quorum-sensing mutants PAO1ΔlasR and PAO1ΔrhlR reached lower bacterial densities than the wildtype. b Comparison of the relative colonization success of strains (ratio of bacterial loads at 0 hpe vs. 30 hpe) revealed that the siderophore-negative strain PAO1ΔpvdDΔpchEF showed significantly reduced ability to remain in the host compared to the wildtype. In contrast, the colonization success of PAO1ΔpchEF and PAO1ΔrhlR was increased relative to the wildtype. Gray shaded areas depict background fluorescence (mean ± standard deviation) of worms exposed to the non-fluorescent, non-pathogenic E. coli OP50. N = number of worms form four independent experiments. *p < 0.05; **p < 0.01; ***p < 0.001