FIG. 7.

C. jejuni mutants defective in motility or chemotaxis are unable to colonize the GI tract of LF mice. Insertion-deletion mutations were made in motB, cheAWY, and fliI in both the 81-176 (A) and 11168 (B) backgrounds. Groups of four to eight mice were inoculated with 10² to 10³ CFU of wild-type or mutant C. jejuni, and stool and tissue samples were collected at the indicated days p.i., with half the group sacrificed at day 7 to assess intestinal colonization. In striking contrast to both wild-type strains, all three mutants failed to colonize the LF C3H mice as demonstrated by analysis of fresh stool and large intestine tissue. Error bars represent the SEM. The limit of detection is 100 CFU/g of stool or tissue. Colonization-level differences between wild-type 81-176 and each of the mutants at day 7 for both stool and large intestine tissue were statistically significant (P values ranging from 0.0014 to 0.0467). For later time points and for analysis in the 11168 background, statistical significance was not achieved despite a lack of colonization by chemotaxis and motility mutants (within the limits of detection), due to smaller sample sizes. Statistical analysis of colonization levels was performed with the unpaired two-sample t test with unequal variances.