Why are chicken farms a breeding ground for antibiotic resistant bacteria?
Scientists from the University of Nottingham are one step closer to understanding how bacteria, such as E. coli and Salmonella enterica, share genetic material which makes them resistant to antibiotics
15 Jan 2024
Antimicrobial resistance (AMR), the capability of organisms to be resistant to treatment with antibiotics and other antimicrobials, is now one of the most threatening issues worldwide. Livestock farms, their surrounding environments and food products generated from husbandry, have been highlighted as potential sources of resistant infections for animals and humans.
In livestock farming, the misuse and overuse of broad-spectrum antimicrobials administered to reduce production losses, is a major known contribution to the large increase and spread of AMR.
The study looked at two important bacteria found in food animals – Escherichia coli and Salmonella enterica – which both show high levels of drug resistance, are common in farming settings, have high levels of transmissibility to humans, and cause food poisoning.
The team collected 661 E. coli and Salmonella bacteria isolates from chickens and their environments in 10 Chinese chicken farms and four abattoirs over a two-and-a-half-year period. Large-scale analysis was carried out using conventional microbiology DNA sequencing and data-mining methods powered by machine learning.
The main findings indicated that E. coli and Salmonella enterica co-existing in the chicken gut, compared to those existing in isolation, feature a higher share of AMR-related genetic material, implement more similar resistance and metabolic mechanisms, and are likely the result of a stronger co-evolution pathway.
The results demonstrated that different bacteria species, co-existing within the same microbial community, are able to share AMR-associated genetic material and end-up implementing similar resistance mechanisms. The discovery has important implications as it affects our understanding of AMR and poses further challenges to the implementation of solutions for surveillance and treatment/control.
The research is a collaboration between experts from the University’s School of Veterinary Medicine and Science, the China National Centre for Food Safety Risk Assessment, New Hope Liuhe Group Ltd in China and Nimrod Veterinary Products Limited.