Figure 3.

Intracellular persistence of the P. aeruginosa reference and clinical strains does not affect lung cell viability. A549, 16HBE14o- and CFBE41o- toxicity after 24 h of intracellular persistence of PAO1, PA14, PAET1, PAET2, and PAET4. The plot shows the normalized values of the absorbance measured at A₅₇₀ to the absorbance of the reference A₆₀₀, as recommended by the PrestoBlue^TM manufacturer. Higher absorbance values indicate greater metabolic activity and therefore viability. Data from three independent experiments are shown, and the error bars indicate the standard error of the mean of representative triplicate experiments. Untreated monolayers were used as controls for viability, and DMSO-treated cells were used as controls for toxicity. A representative picture of the Prestoblue^TM-treated cells is included in the figure in which the gradient from pink (viable cells) to dark blue (toxic cells) is related to the level of cellular toxicity.