A study at the University of Surrey is warning that antibiotic resistance in the environment is a growing but overlooked threat to global health.

Researchers found resistant bacteria are most common in rivers and soil near wastewater and manure.

Air, oceans and green spaces are under-researched, and less than 1% of studies came from low-income countries where the risk is highest.

The team is calling for urgent global action to monitor and understand how resistance spreads in the natural environment.

The comprehensive review, published in Environment International, researched 13,000 studies from 1990 to 2021 to identify patterns and gaps in the topic area.

The team identified 738 studies that focused strictly on non-built, non-industrial environments, such as rivers, fields and air.

The researchers found that antibiotic-resistant bacteria are most often detected in freshwater and soil, particularly in places exposed to pollution from wastewater or manure.

Two bacteria, Escherichia coli and Pseudomonas, were the most studied organisms, while genes conferring resistance to medicines including sulphonamides, tetracyclines and beta-lactams, were very prominent.

We’re told very few studies have explored how antibiotic resistance spreads in the air, oceans or green spaces.

The team also highlighted a lack of research in low-income regions, where the health burden of antibiotic resistance is likely to be highest.