Effect of mutating the cj1169c-cj1170c operon on Campylobacter colonization and transmission in birds. (A) Colonization levels in chickens inoculated with wild-type NCTC11168, KOp50Q, and Comp50Q, respectively. The birds were necropsied on 9 and 12 DAI. Each symbol represents a single bird. Horizontal bars indicate the mean and standard error for each group. (B) Transmission of C. jejuni from seeder birds to naive (non-inoculated) birds. The percentage of naive birds positive for C. jejuni in each group was shown. (C) Cecal colonization levels of the wild-type, KOp50Q, and Comp50Q in naive birds co-mingled with seeder birds. The birds were sacrificed at 9 and 12 days after initiation of co-mingling. Each symbol represents the colonization level in a single bird. The horizontal bars indicate the mean and standard error for each group.