Figure 2

Quorum-sensing dependent phenotypes of P. aeruginosa isolates from tracheal aspirates and intubation devices. Elastase production (A and B), adhesion capacity (C and D) and biofilm formation (E and F) by P. aeruginosa isolates recovered from tracheal aspirates (open squares, TA isolates) and intubation devices (plain circles, ID isolates). Elastolytic activities were determined by ECR assays and expressed as the OD measured at 495 nm per unit of OD 660 nm. The adhesion capacities and biofilm formation were expressed as the percentage relative to the level obtained with the wild-type P. aeruginosa strain PT5. (A, C and E) Results individualized for each patient (8, 12 and 13), error bars correspond to the standard errors of the means. (B, D and F) Mean values and variances for 11 tracheal aspirate isolates and 25 isolates recovered from the intubation devices. For each individual isolate the determinations were performed twice in triplicates.