The climate crisis, already busy melting glaciers and cooking the planet, has now apparently decided to lend a hand to antibiotic resistance - because why should one global health catastrophe have all the fun? A new study published in The Lancet Planetary Health has revealed that rising temperatures and shifting rainfall patterns are accelerating the spread of antibiotic-resistant genes in salmonella, one of the world's most common bacterial diseases.
Antibiotic resistance, which already kills more than 1 million people annually and threatens people of any age in any country, was previously content to be mainly driven by the misuse and overuse of antibiotics. But according to researchers from the UK, France, Australia, Switzerland, and China, climate change is now muscling in on the action. Between 1940 and 2023, climate change was associated with a 10% global increase in salmonella antibiotic resistance genes, the first-of-its-kind study found.
The study analyzed genomes from more than 480,000 salmonella samples across 139 countries collected over 83 years, comparing resistance gene levels with changes in average temperature and rainfall. The relationship turned out to be nonlinear - antibiotic resistance doesn't just steadily rise with temperature, but changes in a more complicated dance depending on both heat and precipitation, suggesting environmental changes can speed up bacterial adaptation to antibiotics.
Some 82% of countries studied saw increases in antibiotic resistance genes in salmonella, with the strongest climate-associated upticks in the Middle East and north Africa, followed by south Asia and sub-Saharan Africa. The authors note that while the study shows a link rather than direct causation, it provides "robust evidence" that climate change is associated with a heightened risk of antibiotic resistance. They urge urgent integration of climate change-mitigation policies, particularly those aligned with the Paris agreement, alongside enhanced antimicrobial stewardship and One Health surveillance - which is a lot of jargon for "please stop making things worse."