FIG. 1.

Effects of pvdQ overexpression and deletion in P. aeruginosa virulence in the C. elegans infection model under standard paralytic conditions. The virulence of the PAO1 wild type and ΔpvdQ and pvdQ-overexpressing mutants was tested on C. elegans by screening only L4 and young adults (black bars) and a mixed population of all developmental stages (white bars). In both cases the PAO1 wild type, the control strain PAO1(pME6032), and the ΔpvdQ mutant resulted in rapid paralysis of the worms with almost a 100% mortality of the population screened. More than 95% of the worms fed with E. coli OP50 survived the 4-h exposure. The results were significantly different for PAO1(pMEpvdQ). When only L4 larvae were used, only 20% of the worms fed on this strain survived. However, in the mixed population more than 75% of the nematodes survived and continued to use this strain as a food source. This mainly included the L1 and L2 developmental stages, with a small number of L3 larvae also surviving.