Prevalence of Campylobacter spp. in chicken, beef, pork and sheep livers in Ireland

Campylobacteriosis is a self-limiting, notifiable disease caused by the Campylobacter genus, a gram-negative bacterium that typically resides in the gastrointestinal tract of many wild and domesticated animals, including pigs, poultry, sheep, and cattle. Though chicken meat is considered the main source of Campylobacter infection in humans, the prevalence of this foodborne pathogen in both poultry and non-poultry species retail liver products in Ireland is less well understood. In this pilot study, a total of 190 samples were analysed, comprising of chicken, beef, pork and sheep liver sourced from four abattoirs in the Leinster region of Ireland during the first half of 2022.Detection results confirmed high prevalence of Campylobacter spp. in poultry liver (35/50, 70%) and lower-than-expected prevalence in bovine (2/45, 4.4%) and porcine (8/50, 16%) liver when compared to the results of other similar studies. The most important finding of this study was the high prevalence of Campylobacter spp. in ovine liver (36/45, 80%). Amongst the 81 positive samples, speciation revealed an overall predominance of C. jejuni (50/81, 61.7%), compared to C. coli (39/81, 48.1%) in all species except porcine. Whole genome sequencing (WGS) using Illumina technology established the genomic diversity, antimicrobial resistance and virulence genes amongst isolates.These results highlight the role of liver as a potential source of Campylobacter spp. to humans, particularly ovine liver.