Multidrug-Resistant Campylobacter coli Strain Found Circulating Across Europe, Study Finds
A new study published in Emerging Infectious Diseases has identified previously unrecognised cross-border circulation of a multidrug-resistant Campylobacter coli sequence type across nine European countries between 2018 and 2025, challenging the long-held view that such infections are sporadic and unrelated. Poultry was identified as the primary animal source, and researchers are calling for coordinated genomic surveillance.
A study published in Emerging Infectious Diseases has identified the previously unrecognised international spread of a multidrug-resistant Campylobacter coli sequence type across Europe between 2018 and 2025, challenging the assumption that campylobacteriosis cases are predominantly sporadic and unrelated.
Researchers used whole genome sequencing (WGS) to analyse 217 isolates drawn from human, animal, food, and environmental sources across nine countries, identifying cross-border genetic clusters of Campylobacter coli sequence type (ST) 10042. The strain was associated with a peak of infections in Portugal and was also detected in Germany, Luxembourg, France, Ireland, Denmark, the Netherlands, the United Kingdom, and Spain, according to Food Safety News.
The investigation was triggered by an increase in Campylobacter coli cases in Portugal in 2022, driven by ST10042. Most of the 217 isolates were from humans, with Portugal contributing the largest number, followed by Germany and Luxembourg. Portugal, Luxembourg, the Netherlands, and Ireland also had animal and food isolates, while environmental isolates were detected only in Portugal and Luxembourg.
Poultry was the dominant animal source: of the 30 animal and human food-derived isolates, 25 were from poultry. Food isolates were recovered from raw chicken and turkey meat in Portugal, and from chicken-based prepared dishes in Luxembourg.
The 104 Portuguese isolates from 2020 to 2025 included one main cluster of 28 isolates and 15 smaller clusters of two to four isolates, with the remainder classified as sporadic. One cluster from Ireland, which included chicken and human isolates from 2021 and 2022, was described as consistent with an outbreak possibly linked to chicken contamination.
Despite low levels of international reporting, the strain was found in databases across Europe, forming distinct genetic clusters across countries and sectors. However, researchers cautioned that the absence of detailed epidemiological metadata means transmission routes and outbreak causality remain unconfirmed.
"These findings demonstrate that Campylobacter 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," the scientists stated.
Campylobacteriosis cases are primarily caused by Campylobacter jejuni, followed by Campylobacter coli, with poultry identified as the main reservoir. WGS-based surveillance has demonstrated that many cases previously considered sporadic occur as genetically related clusters.
Prepared with AI assistance and reviewed by the editorial team.
