FIG. 1.

A/E lesion scores in tissues of gnotobiotic piglets inoculated with nonpathogenic E. coli (NPE), E. coli O157:H7 strain VS97 (luxS mutant), or 86-24 (Parent). The A/E lesion scores of the formalin-fixed intestinal sections were as follows: 0, no A/E lesions with discernable associated bacteria visible throughout the sections; 0.5, infrequent A/E lesions identified only with the immunohistochemical stain; 1, discernable lesions on fewer than 10% of the enterocytes of the sections; 2, discernable lesions on more than 10% but fewer than 50% of the enterocytes; 3, lesions present on 50% or more of the enterocytes. Contingency analysis detected statistically significant differences between the scores for the luxS mutant-inoculated tissues and those for the parent-inoculated tissues from the spiral colons (P < 0.03).