Distribution and characteristics of Campylobacter spp. in turkeys at slaughter

Campylobacter is the leading cause of bacterial foodborne gastrointestinal infection in humans, and poultry is among the most important reservoirs. Turkeys have been shown to frequently carry Campylobacter, and the isolates recovered from turkeys show high antimicrobial resistance. We studied the prevalence of Campylobacter in Finnish slaughter turkeys during 2013-2023 from the monitoring data of a Finnish turkey slaughterhouse, covering 1856 turkey flocks originating from 41 farms over the monitoring period. Additionally, we used whole-genome sequencing to identify bacterial species, resistance profiles, sequence types, and core genome allelic profiles for 103 Campylobacter isolates from turkey faecal samples collected at the slaughterhouse between 2013 and 2021. In total, 9.5 % of the flocks and 82.9 % of the farms were Campylobacter positive. The prevalence varied significantly between years, months, and farms. Campylobacter jejuni (87.6 %) was the most common species followed by Campylobacter coli (4.0 %) and Campylobacter lari (1.1 %). We obtained 34 sequence types, with ST45 being the most common (20.2 % of the isolates). Genetically closely related isolates originated mostly from the same farm with a tight temporal connection. Five antimicrobial genotypic resistance profiles were identified. Most of the isolates carried only the blaOXA gene, and only one Campylobacter isolate carried several resistance genes. We showed that Campylobacter prevalence and the occurrence of antimicrobial resistance genes in the isolates is low in Finnish slaughter turkeys. Further, we demonstrated that Campylobacter spread between the flocks on the same farm, but the same STs did not persist.