FIG 7.

Bactericidal effect of S. maltophilia wild-type and virB10 mutant strains on various strains of P. aeruginosa. S. maltophilia K279a (WT), virB10 mutant NUS15 (virB10), or complemented mutant NUS15(pvirB10) (virB10/virB10+) was mixed with P. aeruginosa strain 7700 (A), PAO1 (B), and PAK (C) at a ratio of ∼100:1 and spotted onto LB agar, and after 2 h of incubation, the numbers of each strain were determined by plating dilutions of the entire bacterial growth area on selective media. The results presented are the CFU at t = 0 h and t = 2 h for each time that the P. aeruginosa strain had been coincubated with the S. maltophilia WT, mutant, or complemented mutant strain (A to C, left) as well as the CFU at t = 0 h and t = 24 h for the three S. maltophilia strains under each growth condition (A to C, right). Asterisks indicate significant differences in CFU obtained at t = 0 versus t = 2 h (*, P < 0.05; **, P < 0.01). Data are presented as the means and standard deviations of results from three independent experiments (n = 3 each).