Birds and bats may be contributing to the spread of superbugs in cities in developing countries, according to a new study.
The study, published in The Lancet Planetary Health, revealed that birds who scavenge and eat seeds (like storks and bats) in Nairobi, Kenya, have high levels of bacteria like E. coli that are resistant to antibiotics.
The researchers from the University of Liverpool and the International Livestock Research Institute point to poor waste management as a leading cause, because these urban birds and bats feed from sewage plants, garbage lots, and waste from abattoirs, so they ingest superbugs from waste from humans and livestock.
They also warn that if these superbugs are transmitted to migrating birds, they could then make their way to Europe — further expanding on the threat of antimicrobial resistance (AMR).
People (and animals) around the world are becoming resistant to antibiotics, which means that common infections that were once easy to treat could one day become deadly.
AMR causes 700,000 deaths per year, and by 2050, that number could reach 10 million worldwide, according to the 2014 Review on Antimicrobial Resistance.
For this study, researchers took faeces samples from wildlife, livestock, and humans across multiple areas in Nairobi to test for E. Coli and incidences of resistance to 13 antibiotics.
They collected 2,000 wildlife samples and detected the presence of E. coli in 485 cases. Half of these 485 were resistant to antibiotics like cephalosporins and fluoroquinolones, which are commonly used to treat illnesses like respiratory and urinary tract infections.
The study found higher levels of multi-drug resistant superbugs in humans and livestock, but the authors warn that wildlife like birds could spread AMR in a significant way. Poorly managed waste, combined with livestock living close to people, make it easy for wildlife to ingest the bugs and fly away to other cities — or continents, as some species in Nairobi migrate to Europe.
“Since wildlife are not treated with antibiotics, this is indicative of how pervasive AMR is in urban environments. Species that move freely across cities and further afield could disseminate resistance acquired in urban areas more widely,” Dr. James Hassell, lead author of the study, said in a University of Liverpool news release. “As many scientists and policymakers are now realising, we cannot address the rise of antimicrobial resistance without focusing on the environmental, ecological and social settings in which humans exist.”
In other words, the issue of AMR does not just impact antibiotics — it’s an ecological threat that needs to be approached not just from a medical or health perspective, but also from an environmental one, Eric Fèvre, professor of veterinary infectious diseases at the University of Liverpool, explained.
AMR became part of the United Nations agenda in 2016. There is no one singular cause of AMR, as it’s the result of overuse of antibiotics by humans, but also in animals and the environment, due to agricultural practices, food trade, and population migration — which means that the global response will need to be comprehensive.
“This paper shows that contamination of urban environments with AMR is a serious issue. This is not just specific to Nairobi but findings can be extrapolated to other cities in Africa,” Professor Eric Fèvre, a joint appointee at the University of Liverpool and ILRI, said in the University of Liverpool news release. “We need to take an ecological approach to addressing this threat. Urban cities can address this by better urban planning, better waste disposal, and better livestock husbandry practices. This can go far toward disrupting AMR exchange between wildlife, livestock and humans.”