Contributions of whole-genome sequencing to the epidemiological monitoring of Campylobacter spp. in France.

Next-generation sequencing techniques have revolutionized the epidemiology and understanding of Campylobacter spp. infections. In this study, we present the results of a next-generation sequencing (NGS) analysis conducted in 2024 on 2,360 Campylobacter spp. strains isolated in France, including 1,959 Campylobacter jejuni, 358 Campylobacter coli, and 43 Campylobacter fetus strains. We describe the diversity of circulating strains and provide an overview of the main mechanisms of antibiotic resistance. We identified a variety of resistance mechanisms, particularly for resistance to group A penicillins. Notably, we identified a novel promoter upstream of the gene encoding a beta-lactamase. Using source attribution markers for C. jejuni and C. coli, we identified poultry as the main vector for infections by these two species. However, ruminant meat accounts for a significant proportion of C. jejuni infections in France. This study demonstrates how a sequencing strategy can generate large-scale and high-resolution data for understanding Campylobacter spp. infections.