FIG 3.

CpxRA is essential for efficient colonization and infection of C57BL/6J mice. C57BL/6J mice were infected with the indicated C. rodentium strains. Mice were sacrificed at 12 days postinfection. Each mouse in the experiment is represented by a single point. The median for each group is indicated on the graph by horizontal bars. Asterisks indicate statistical significance (*, P < 0.05; ***, P < 0.001), as determined by Kruskall-Wallis analysis and Dunn's multiple-comparison post hoc analysis. (A) Numbers of CFU per gram of colon from each animal were determined by serial dilution plating. (B) Prior to dissection, each animal was weighed, the spleens were then removed and weighed individually, and spleen indexes were calculated [√(weight of spleen × 100/weight of mouse)]. (C) Numbers of CFU per gram of feces were determined for mice infected with the wild-type (circles), ΔcpxRA (triangles), or ΔcpxRA::cpxRA (squares) strain by serial dilution plating. LOD indicates the limit of detection.