FIG 3.

NTHi infection significantly decreases P. aeruginosa (Pa) colonization/persistence in mouse lung. Either BALBc/J mice were intratracheally infected with NTHi (NTHi Hi-1r) 24 h prior to introduction of mPA (mPA 08-31) in a sequential fashion or the species were introduced at the same time (concurrently) and assessed 48 h postinfection. (A) Bacterial counts of NTHi and P. aeruginosa in the lung homogenates enumerated by plate counting. (B) Bacterial counts of P. aeruginosa in the lung homogenates, comparing sequential infection and concurrent infection. (C and D) Severity of disease indicated by H&E-stained lung sections (×200 magnification) (C) and semiquantitative grading by a pathologist (L.N.) (D). (E) Total cell counts in BALF samples quantified by differential cell counts. (F) Percentage of PMNs in the BALF samples. Values are mean ± SEM (n = 10). LOD, limit of detection. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001, Kruskal-Wallis test with Dunn’s multiple-comparison test.