Characterization and Prevalence of Campylobacter spp. From Broiler Chicken Rearing Period to the Slaughtering Process in Eastern China

Abstract

<i>Campylobacter</i> is one of the most important foodborne pathogens worldwide, and poultry is regarded as the main reservoir of <i>Campylobacter</i>. The contamination of <i>Campylobacter</i> in broiler chickens at the farm level is closely related to the transmission of <i>Campylobacter</i> in the poultry production chain. This study identified 464 <i>Campylobacter</i> isolates from 1,534 samples from broiler rearing period and slaughtering process including 233 <i>Campylobacter jejuni</i> isolates and 231 <i>Campylobacter coli</i> isolates. We have observed a dynamic distribution of <i>Campylobacter</i> during broiler chicken production, that 66.3% of Campylobacter isolates were <i>C. jejuni</i> during broiler rearing period, while <i>C. coli</i> occupied 60.4% of Campylobacter isolates during the broiler slaughtering process. A tag-label method allowed us to track the dynamic of <i>Campylobacter</i> in each broiler chicken from 31-day age at rearing to the partition step in the slaughterhouse. At the 31-day during rearing, 150 broiler chicken were labeled, and was tracked for Campylobacter positive from rearing period to slaughtering process. Among the labeled broiler, 11 of the tracking broiler samples were able to detect <i>Campylobacter</i> from rearing period to slaughtering. All <i>Campylobacter</i> isolates from the 11 tracking samples were sequenced and analyzed. <i>C. jejuni</i> isolates were divided into four STs and <i>C. coli</i> isolates were divided into six STs. Isolates with identical core genome were observed from the same tag-labeled samples at different stages indicating a vertical transmission of <i>Campylobacter</i> in the early broiler meat production. Meanwhile, the core genome analysis elucidated the cross-contamination of <i>Campylobacter</i> during the rearing period and the slaughtering process. The virulotyping analysis revealed that all <i>C. jejuni</i> isolates shared the same virulotypes, while <i>C. coli</i> isolates were divided into three different virulotypes. The antimicrobial resistance gene analysis demonstrated that all <i>Campylobacter</i> isolates contained at least two antibiotic resistance genes (ARGs), and the ARG profiles were well-corresponding to each ST type. Our study observed a high prevalence of <i>Campylobacter</i> during the early chicken meat production, and further studies will be needed to investigate the diversity and transmission of <i>Campylobacter</i> in the poultry production chain.