FIG 1.
P. aeruginosa Psl production antagonizes growth of S. aureus. (A) S. aureus USA300 was grown in coculture with either P. aeruginosa PAO1 or ΔPpsl on solidified medium using a cross-streak assay. Arrows point to the inhibition zones of S. aureus growth that were observed after overnight incubation. (B) S. aureus survival over the course of 8 h when grown alone or cocultured with PAO1 or ΔPpsl. Data are means and standard deviations (SD); individual points indicate the means for biological replicates (N = 5; n = 3). Significance was determined using Student’s t test. *, P < 0.05 compared to PAO1. (C) S. aureus survival when cocultured for 7 h with PAO1, ΔpslD, or the complemented ΔpslD/pslD+ strain. N = 4; n = 3. Data are means and SD; individual points indicate biological replicates. S. aureus survival (B and C) is presented as CFU normalized to the starting CFU at 0 h. Significance was determined using a one-way ANOVA. *, P < 0.05 compared to PAO1.