ABOVE: The new study found that wild birds living close to humans in cities are likely to carry bacteria with antimicrobial resistance (AMR). Image credit: Viktor Keri: Unsplash
Research from the Ineos Oxford Institute for Antimicrobial Research at Oxford University has revealed that wild birds, such as ducks and crows, living near human populations—especially in urban areas—are likely to carry bacteria with antimicrobial resistance.
This highlights the urgent need for policymakers and health services to address the various ways antibiotic-resistant bacteria can spread beyond hospital settings.
AMR occurs when bacteria and other microbes become resistant to antibiotics that would typically kill them.
In 2022, around 58,224 people in the UK suffered severe antibiotic-resistant infections, resulting in 2202 deaths.
Globally, AMR was linked to 1.27 million deaths in 2019, with the World Health Organisation classifying it as one of the most pressing global public health and development challenges.
In a new study published in Current Biology, researchers analyzed 700 bacterial samples from the gut microbiomes of 30 wild bird species across eight countries.
They focused on Campylobacter jejuni, a bacteria that commonly causes diarrhea and can be transmitted between animals and humans (a zoonotic disease).
Through genomic analysis, the study explored the diversity of C. jejuni strains and the presence of AMR genes, using a novel statistical model to examine how bird behavior and location influenced these factors.
AMR-related genetic markers were found in all bird species studied.
Antimicrobial resistance occurs when disease-causing microbes such as bacteria become resistant to antibiotics that would otherwise kill them. Image credit: Anna Shvets: Pexels
Birds living near humans, like crows and ducks, carried a wider range of bacterial strains and up to three times more AMR genes compared to birds in more remote areas.
This included genes resistant to commonly used antibiotics such as fluoroquinolones and beta-lactams.
Professor Samuel Sheppard, lead author of the study and Digital Microbiology and Bioinformatics Lead at the Ineos Oxford Institute, said: “AMR is a complex issue affecting human health, animals, and the environment.
Wild birds can spread AMR over long distances to livestock and pets, which has implications for agriculture, animal welfare, and food security.”
Urban animals are exposed to various sources of AMR bacteria, like wastewater-contaminated rivers, and may play a role in transmitting these bacteria to humans.
As urbanization continues and human populations expand, greater contact between humans and wild animals increases the risk of spreading zoonotic pathogens.
Despite the global health threat posed by AMR, research on how habitat disruption impacts the bacteria in animals living close to humans is limited.
This study offers valuable quantitative evidence of AMR transmission across ecosystems and highlights the interconnected roles of humans, animals, and the environment in spreading AMR.
Given that birds can travel great distances, species like crows and thrushes, which thrive in urban areas, could contribute significantly to AMR spread.
The data from this study will be crucial for future research aimed at understanding the broader impact of human expansion on zoonotic pathogens and AMR.
The study, “Proximity to humans is associated with antimicrobial resistant enteric pathogens in wild bird microbiomes,” is published in Current Biology.
The research included samples from Canada, Finland, Italy, Lithuania, Japan, Sweden, the UK, and the USA.