INHIBITION OF CAMPYLOBACTER-JEJUNI COLONIZATION IN CHICKS BY DEFINED COMPETITIVE-EXCLUSION BACTERIA

Campylobacter enteritis in humans has been linked to consumption of ch icken. Reducing Campylobacter jejuni colonization in chickens can pote ntially reduce Campylobacter infections in humans. In this study, the reduction of C jejuni colonization in chicks by oral administration of defined competitive exclusion (CE) cultures, 2.5% dietary carbohydrat es, or CE cultures and carbohydrates was examined. Prevention, elimina tion, or direct challenge of Campylobacter infection was simulated by administering treatments before, after, or at the same time as that of the Campylobacter inoculation. Additionally, the effect of maintainin g high levels of protective bacteria was evaluated by administering CE cultures on days 1 and 4 (booster treatment). All treatments reduced C. jejuni colonization. Protection by aerobically grown CE cultures wa s not statistically different from that by anaerobically grown CE cult ures. A combination of Citrobacter diversus 22, Klebsiella pneumoniae 23, and Escherichia coli 25 (CE 3) was the most effective CE treatment . Maintaining high numbers of CE isolates by administering CE boosters did not increase protection. The greatest reduction of Campylobacter colonization was observed in schemes to prevent or eliminate C. jejuni infection. C. jejuni was not detected in the ceca of birds receiving the prevention treatment, CE 3 with mannose, representing a 62% reduct ion in the colonization rate. The protection factor (PF), a value comb ining the colonization rate and the level of infection, for CE 3 with mannose was high (>13.2). Fructooligosaccharides alone strongly preven ted Campylobacter colonization. Only 8% of the chicks in this group we re colonized, with a PF of >14.3. Lactose and CE 3 greatly reduced est ablished infections (PF, >20.1); C. jejuni was found in the ceca of on ly 5% of the chicks treated with this combination compared with 80% of the control chicks. While specific prevention and elimination treatme nts were highly protective, they were not statistically more protectiv e than the best challenge and booster treatments. Thus, CE cultures an d carbohydrates can be effectively administered to reduce Campylobacte r colonization.