Abstract

This longitudinal survey followed the life cycle of a New Zealand broiler flock to investigate sources of flock colonization by Campylobacter. Samples were collected at frequent intervals from potential Campylobacter reservoirs and sources, transmission routes for Campylobacter ingress into the broiler shed, and to monitor flock colonization. Of the 738 samples, 200 (27%) tested positive for Campylobacter. Campylobacter species from sample isolates included 316 Campylobacter jejuni, 39 Campylobacter coli, and 8 Campylobacter lari isolates; only C. jejuni was isolated from chickens. C. jejuni isolates (n = 199) were sequenced and consisted of seven sequence types (STs); the most abundant was ST6964 (105 isolates). Most flock isolates were ST6964 (44 isolates) or ST50 (27 isolates). ST6964 isolates closely matched those from the previous flock and another age-matched flock on the same farm, supporting a role for an on-farm reservoir contaminating flocks. There were six STs from catching crew and equipment isolates; the most prevalent were ST6964 (19 isolates) and ST50 (21 isolates). The close genetic match, high Campylobacter prevalence in catching samples (59/130, 45%), and the timing of flock colonization occurring closely following catcher presence in the shed support that catchers and equipment might also contaminate the shed and flock from prior flocks that they visited. There was no evidence for wildlife, feed, drinking water, breeder flock, or shed litter as sources of the Campylobacter genotypes colonizing the flock. Taken together, this study identified key areas where the poultry industry might focus on-farm risk management practices to reduce colonization of broiler flocks by Campylobacter.

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