FIG. 6.

Quantitation of bacterial burden and histopathological lesions. Mice (n = 4 to 6 per group), infected with 25 CFU of WT Schu S4, the Δctu mutant, and the transcomplemented Δctu+pctu strain were sacrificed at the indicated times. The bacterial burden in the lungs, liver, and spleen (A) and the histopathological lesions in the lungs (B) were quantitated. The results are expressed as the means ± SEs and are cumulative of the results of two independent experiments conducted. P values were determined using one-way ANOVA. ND, not detected; *, P < 0.05; **, P < 0.01; and ***, P < 0.001.