Figure 2.

CF newborn ferret lungs fail to irradiate Pseudomonas aeruginosa. (A) Schematic of bacterial challenge assays. Newborn non-CF and CF kits (6–24 h old) were challenged via intratracheal injection with 1.5 × 10⁴ CFU of ampicillin-resistant P. aeruginosa (PA01) or erythromycin-resistant Staphylococcus pseudintermedius into the airways for 6 hours. The lung and tracheal tissue was then harvested and homogenized. The total number of CFU was determined by plating serial dilutions of lung homogenate on Luria-Bertani agar plates containing the appropriate antibiotic and counting colonies the next day. (B and C) Plot of results of in vivo bacterial challenge after intratracheal injection. For each experiment, input CFU was determined as well to control for variation on different days, and the total lung CFU was calculated as a percentage of the input CFU. Average input CFU (100%) is denoted with a line on each graph. Error bars represent SEM. *P < 0.05, ***P < 0.001, using the nonparametric Kruskal-Wallis test with Dunn’s multiple comparison post test. (B) n = 8 non-CF, 12 CF animals; (C) n = 9 non-CF, 6 CF animals.