FIG. 3.

P. aeruginosa in vitro traversal assay using multilayered human corneal epithelia that were preexposed to PAO1 culture supernatant (1:5 dilution in KGM-2 medium) for 4, 8, or 12 h before inoculation with 10⁶ CFU of strain PAO1 for 8 h in the continued presence of the supernatant. Controls were treated with KGM-2 medium only. Viable counts were taken from the apical compartment (A), internalized bacteria were assessed by gentamicin survival (B), and viable traversed bacteria (basal compartment) were counted (C). *, P < 0.001 in each instance versus untreated controls (ANOVA with Fisher PLSD post hoc analysis). Data representative of three experiments are shown. Note that the x axis represents different supernatant pretreatment times prior to PAO1 inoculation.