Multisectoral Emergence of Multidrug-Resistant Campylobacter coli Sequence Type 10042 Lineage, Europe, 2018-2025.

Campylobacter spp. remain the leading bacterial cause of foodborne gastroenteritis in Western countries. We report sustained, previously unrecognized circulation of a multidrug-resistant Campylobacter coli sequence type 10042 lineage across Europe during 2018-2025. Whole-genome sequencing of 217 isolates from 9 countries spanning human, animal, food, and environmental sources identified cross-border clusters, including a large lineage linking primarily Portugal and Luxembourg, as well as Germany, Ireland, Spain, and the United Kingdom. Genomic data indicates ongoing clonal expansion with increasing diversification over time. Isolates exhibited a conserved multidrug-resistant phenotype, including resistance to fluoroquinolones, tetracyclines, and β-lactams; reduced susceptibility to carbapenems was observed. Resistance was associated with GyrA Thr86Ile, tet(O/32/O)/tet(O) genes, and blaOXA-61 promoter variants; variation in porA was linked to variable amoxicillin/clavulanic acid and ertapenem susceptibility. Those findings demonstrate that C. coli infections can involve sustained international transmission rather than sporadic cases and highlight the need for coordinated, cross-sector genomic surveillance to detect emerging antimicrobial-resistant lineages.