Development of an experimental model of Campylobacter jejuni intestinal colonization in commercial turkeys

Abstract

Abstract The cecum is the main site where poultry are asymptomatically colonized by thermophillic Campylobacter spp. Consumption of contaminated poultry products is one of the main sources of human campylobacteriosis, for which Campylobacter jejuni is responsible for approximately 90% of the cases. In chickens, experimental models of C. jejuni colonization to examine the host-response have been established, but a model remains to be developed for commercial turkeys. We sought to develop a model to characterize intestinal colonization and host response in commercial turkeys using mutants of C. jejuni (strain NCTC 11168) constructed to express different antibiotic resistance markers (chloramphenicol (CjCm) or kanamycin (CjK)). Turkey poults were colonized by oral gavage at 21 days of age with up to 5×108 cfu of either CjCm, CjK or sterile PBS. Up to 8 poults/treatment were euthanized at days 2, 7 and 14 post-exposure and intestinal samples were assessed for colonization and host-response. Both mutants were consistently recovered from cecum, but not ileum, throughout the study, with ~107 cfu/g detected from cecal contents at day 14 post-exposure. Mild inflammatory changes were histologically noted in the cecum and cecal tonsil of CjCm or CjK colonized poults at days 7 and 14 post-exposure. Using IHC, Campylobacter antigen was detected between cecal villi by day 7, indicating persistent colonization. Host-response for cytokines (IL-6, -8, -10, -17A, -22 and others) and β-defensins was analyzed by qRT-PCR from intestinal tissues. This study demonstrates that CjCm and CjK persistently colonize the cecum of commercial turkeys and will be useful to evaluate strategies to reduce intestinal colonization by C. jejuni in turkeys and promote food safety.