A-Z Index × Submit A-Z Index × Submit A-Z Index Search Dropdown × Submit Facebook Twitter LinkedIn Syndicate Emerging Infectious Disease journal ISSN: 1080-6059 Disclaimer: Early release articles are not considered as final versions. Any changes will be reflected in the online version in the month the article is officially released.
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 bla OXA-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.
Since 2005, campylobacteriosis has been the most frequently reported foodborne zoonosis in the European Union (EU); 168,396 human cases were reported in 2024 ( 1 ). Infections affect all age groups but are most severe in young children, the elderly, and immunocompromised persons ( 2 ). Campylobacteriosis typically manifests as bloody or watery diarrhea, abdominal cramping, fever, vomiting, and nausea ( 3 , 4 ). Severe or prolonged infections can lead to complications, such as bacteremia, that occasionally require hospitalization or result in death ( 3 , 4 ). Antimicrobial therapy is warranted in those cases, highlighting growing concerns regarding Campylobacter antimicrobial resistance (AMR), particularly to fluoroquinolones, macrolides, and carbapenems ( 4 , 5 ).
Campylobacteriosis cases are primarily caused by Campylobacter jejuni (≈90%) and C. coli (≈10%) ( 2 ). Poultry is the main reservoir, although livestock commodities, domestic and wild animals, humans, and contaminated water or soil also contribute to transmission ( 2 , 6 ). Although most Campylobacter infections have historically been considered sporadic ( 7 ), recent whole-genome sequencing (WGS)–based surveillance has demonstrated that many cases occur as genetically related clusters ( 8 – 12 ).
Genomic surveillance leveraging WGS-based approaches, including whole-genome and core-genome multilocus sequence typing (MLST), has markedly enhanced identification of outbreaks, investigation of transmission pathways, and detection of emerging epidemic lineages, providing high-resolution insights into genetic diversity, AMR determinants, and source attribution ( 8 – 12 ). WGS data also expand knowledge on novel AMR determinants, such as porA gene, which encodes the major Campylobacter outer-membrane porin and whose allelic variants might reduce β-lactam and carbapenem influx through altered mem…