FIG 6.

Colonic pathology in rabbits infected with WT or mutant S. flexneri. (A) Histopathological scores of heterophil infiltration in colonic sections of animals infected with indicated strains of S. flexneri. Means ± standard error of the mean values are superimposed. Statistical significance was determined using a Kruskal-Wallis test with Dunn’s multiple-comparison posttest; comparisons that are nonsignificant are not labeled. (B to D) Representative hematoxylin-and-eosin-stained colonic sections from rabbits infected with the indicated strains 36 hpi. In panel B, the inset to the right displays the magnified version of the boxed region of the larger micrograph. Black arrowheads point to heterophils (pink cytoplasm, multilobular darkly stained nucleus). Bar, 100 μm. In panel C (MxiM mutant), the inset to the right displays a magnified version of the boxed region of the larger micrograph. Arrowheads point to heterophils. Bar, 100 μm.