FIG 6.
CpxRA is required for efficient infection of C3H/HeJ mice. C3H/HeJ mice were infected by oral gavage with 2 × 108 CFU of the wild-type, ΔcpxRA, or ΔcpxRA::cpxRA C. rodentium strain. (A) Each data point represents the percentage of mice still surviving from an initial population of 9 to 12 mice. Statistical analyses were performed by using a Gehan-Breslow-Wilcoxon test, and asterisks indicate statistical significance (***, P < 0.001). (B) Numbers of CFU per gram of feces (day 3 and day 6) or colon (day 9) 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. The median for each group is indicated on the graph by horizontal bars. Asterisks indicate statistical significance (**, P < 0.05; **, P < 0.01), as determined by a Kruskall-Wallis test and Dunn's multiple-comparison post hoc analysis.