Figure 2

Effect of multi-drug resistant (MDR) clinical isolates of P. aeruginosa on transepithelial resistance (TER) of Caco-2 monolayers. (A) TER of Caco-2 cells measured dynamically during co-incubation with MDR P. aeruginosa. PA103, well known cytotoxic strain; PAO1, well known invasive laboratory strain; ATCC 27853, a prototype laboratory strain used as a susceptible control in the antibiotic resistance assay; 190, a Gm^S environmental isolate; and 180, a Gm^R environmental isolate were used as non-MDR controls. TER is expressed as % of control TER in confluent Caco-2 cells. (B) MDR clinical isolates and control non-MDR P. aeruginosa strains are arranged in descending order of their ability to affect the TER of Caco-2 cells expressed as ΔTER/hour normalized to the initial bacterial cell density. (C) The most virulent strain, #1, induced a fall in TER even at an extremely low concentration of 10³ CFU/ml. Data are mean ± SD (n = 3).