A widely used weedkiller could be playing an unexpected role in the rise of dangerous antibiotic-resistant bacteria, according to new research.
Scientists have found that glyphosate—the active ingredient in many common herbicides—may help certain bacteria survive and spread, even in places far from hospitals.
Antimicrobial resistance (AMR) is already a major global health threat, causing an estimated 1.1 to 1.4 million deaths each year.
It happens when bacteria evolve so that antibiotics no longer work against them.
Traditionally, this problem has been linked to the overuse or misuse of antibiotics. However, this new study suggests that other chemicals in the environment, such as weedkillers, may also contribute.
The research was led by Dr. Daniela Centrón and her team at the Institute of Medical Microbiology and Parasitology in Buenos Aires.
Their findings were published in the journal Frontiers in Microbiology.
The scientists discovered that many bacteria commonly found in hospitals and known for being resistant to multiple antibiotics can also tolerate high levels of glyphosate.
To investigate this, the team collected 68 bacterial samples from sediments in a protected wetland area in Argentina’s Paraná delta.
Although glyphosate is not used directly in this reserve, nearby agricultural areas frequently apply it. The researchers tested these samples against 16 common antibiotics, as well as pure glyphosate and commercial herbicides.
They also compared these environmental bacteria with strains collected from hospitals and agricultural sites.
As expected, the hospital bacteria showed strong resistance to many antibiotics, including carbapenems, which are often used as a last resort. Alarmingly, all of these hospital strains were also highly resistant to glyphosate.
This means that if resistant bacteria from hospitals enter the environment—such as through untreated wastewater—they may survive and even thrive in agricultural soils where glyphosate is present. In other words, farms could become a new breeding ground for “superbugs.”
The study also found that bacteria from different environments shared similar resistance patterns. Certain groups, such as Enterobacter, were able to survive extremely high levels of glyphosate, while others, like Bacillus, were more sensitive. Overall, bacteria that were closely related genetically tended to show similar resistance, regardless of whether they came from hospitals, farms, or natural areas.
The researchers believe that glyphosate may act as a “selection pressure,” similar to antibiotics, encouraging the growth of resistant bacteria. These bacteria can then spread between environments through water systems, linking hospitals, farms, and natural ecosystems.
Glyphosate has already been controversial for other reasons, including concerns about its effects on wildlife and its possible link to cancer. Some European countries have restricted its use in public spaces or for household purposes.
The study’s authors suggest that regulators should take a closer look at how pesticides like glyphosate might contribute to antibiotic resistance. They recommend testing new chemicals for their potential to promote resistance and adding warning labels about this risk.
Overall, the findings highlight a growing concern: the fight against superbugs may not be limited to hospitals and medicines—it may also depend on how we manage chemicals in the environment.
