Scientists from the Ineos Oxford Institute for antimicrobial research (IOI) and the Department of Biology have estimated that 80% of human Campylobacter infections in Oxfordshire are associated with poultry meat, and that many of these infections are resistant to antibiotics.
Campylobacter is the world’s leading bacterial cause of diarrhoeal disease, causing more than 3.5 times as many gastroenteritis cases in the UK each year as all other monitored foodborne bacteria combined.
While rarely fatal, Campylobacteriosis can cause vomiting, diarrhoea, fever, and, in rare cases, could lead to paralysis. Rising rates of antimicrobial resistance (AMR), which occurs when bacteria resist drugs designed to kill them, are making Campylobacter infections increasingly difficult to treat.
The findings come from an ongoing 22-year project funded by the Food Standards Agency (FSA) and PATH-SAFE programme, highlighting emerging trends in antibiotic-resistant infections across the UK.
Tracking resistance from farm to fork
Researchers collected bacterial samples from infected hospital patients, as well as from poultry, livestock, and less frequently studied sources like wild birds and deer. They used genetic sequencing to compare bacterial strains in humans and animals. This enabled them to trace human infections back to their animal sources, revealing the origin of resistant bacteria that move through the food production chain.
According to their analysis, poultry accounts for approximately 80% of human infections, making it the dominant source of Campylobacter. The highest antibiotic-resistance levels were found in strains isolated from chickens, three of which showed almost 100% resistance to some antibiotics – suggesting that reducing transmission from poultry is key to protecting human health.
Despite an overall reduction in antimicrobial use on UK farms, resistance to two major classes of antibiotics - fluoroquinolones and tetracyclines - has increased since the previous study period of 2015 to 2018. However, resistance to macrolide and aminoglycoside antibiotics remains low, indicating that responsible antibiotic use has helped slow the rise of resistance in some areas.
Professor Sam Sheppard said:
“Antibiotic use in UK farms has fallen substantially over the past decade, reflecting sustained efforts by farmers, veterinarians, and regulators. Our findings show this progress matters, as decreased use has helped keep resistance to some important antibiotics low.
However, this alone is not enough. Preventing infections, monitoring the entire food supply chain, and responsible use of antimicrobials in humans are all essential to tackling AMR.”
Combatting Campylobacter
Thorough cooking destroys Campylobacter, meaning many infections can be prevented in the kitchen.
Cross-contamination during food preparation is a major risk for spreading bacteria, and the Food Standards Agency recommend strict hygiene practices like not washing raw chicken.
Professor Martin Maiden said:
“Parts of this study took place during the COVID-19 lockdowns, allowing us to study how reduced travel and eating out affected infections. We saw very little change, suggesting most infections come from food consumed at home. This highlights the importance of comprehensive, science-based food hygiene education to reduce infection rates.”
The study recommends that existing biosecurity practices on poultry farms, which aim to keep farms clean and easy to disinfect, should be strengthened by improved animal welfare measures.
Dr Frances Colles said:
“Any improvements must be practical, affordable and beneficial to both consumer and industry, and an updated focus on chicken well-being could, for example, improve gut health and resilience to disease, cutting down on the need for antibiotics.”
Looking ahead, researchers emphasise the need for interdisciplinary studies across the food supply chain, involving farmers, retailers, and public health bodies like the UK Health Security Agency (UKHSA), Food Standards Agency (FSA) and the Animal and Plant Health Agency (APHA). Future studies could explore how Campylobacter spreads in poultry, how AMR persists without the continued pressure of antibiotic use, and how human behaviours influence infection risk.
