FIG. 5.
Colitis caused by the Salmonella wild-type strain, an fliGHI mutant, and a cheY mutant. Three groups of 10 streptomycin-pretreated mice were treated with 10% bicarbonate p.o. prior to infection for 24 h with 5 × 107 CFU of serovar Typhimurium strains SL1344 (wild type), M913 (fliGHI), and M935 (cheY). The data were obtained from two independent experiments performed with groups of five mice. (A to D) Bacterial loads in the cecal contents (A), the mLN, (B), the spleen, (C), and the liver (D). The dotted lines indicate the limits of detection, and the solid horizontal lines indicate the medians. (E) Histopathological analysis. HE-stained sections of cecal tissue were scored for edema in the submucosa (black bars), PMN infiltration (PMN inf.; medium gray bars), reductions in the numbers of goblet cells (dark grey bars), and desquamation, erosion, and ulceration of the epithelial layer (light gray bars) (see Materials and Methods). The scores are expressed as stacked vertical bars. The total pathological score (sum of the separate scores) and the bacterial load were statistically analyzed by using the exact Mann-Whitney U test (in comparison to wild-type strain SL1344). S. Tm, Salmonella serovar Typhimurium; wt, wild type; stat. anal., statistical analysis; NS, not statistically significant (P ≥ 0.05).