FIG. 5.

Salmonella serovar Typhimurium-induced intestinal pathology. Mice were treated with the specified antibiotics in drinking water for 2 days. Doses are in mg/liter. Following antibiotic withdrawal, mice were infected with 2.7 × 10⁸ CFU of Salmonella serovar Typhimurium for 3 days. Experiments were repeated three times with six mice per group. The results of a representative experiment are shown. P values were calculated using Kruskal-Wallis with Dunn's posttest, with a 95% confidence interval. C, control; Sm, streptomycin; Vanc, vancomycin. (A) Tissues were harvested, fixed in formalin, and stained with H&E. Antibiotic-treated Salmonella serovar Typhimurium-infected sections show escalating pathology, indicated by rising levels of inflammatory infiltrate starting from the submucosa and spreading to the lumen, as well as increasing epithelial disorganization, indicated by mucinous plugs in crypts, mounting epithelial regenerative changes, desquamation, and the presence of dead epithelial cells in the lumen. Arrowheads indicate the lumen. (B) Quantification of indicators of pathology. Groups marked with an asterisk are significantly different from the respective C group (P < 0.05).