Fig. 5. Optimization of the A. baumannii dose in the development of the acute pneumonia model at 24 and 48 h after challenge. Bacterial burdens in lungs (a), spleens (b) and stomachs (c) were presented as mean±sd. The limit of detection is 1 c.f.u. g−1, i.e. log (c.f.u. g−1) = 0. Body weight change at 24 and 48 h post-challenge (d) was presented as mean±sd. n=7 for high- and medium-dose groups; n=2 for PBS control. These data represent three independent experiments. Statistical differences were determined using one-way ANOVA (P value < 0.05) (*P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001; ****P ≤ 0.0001).