A laboratory study has found that bacteria resistant to last‑resort antibiotics in hospitals can also survive concentrations of glyphosate, the active ingredient in the widely used herbicide Roundup. Researchers say the results suggest that routine agricultural applications of the chemical could create environmental “refuges” for superbugs, potentially widening the gap between clinical and environmental reservoirs of antimicrobial resistance (AMR).
What happened
Scientists at an unnamed research institute examined clinical isolates of carbapenem‑resistant Enterobacteriaceae (CRE) and other multidrug‑resistant organisms collected from hospitals across several countries. In a series of growth‑inhibition assays, the bacteria were exposed to glyphosate at levels ranging from 0.5 g/L to 5 g/L—concentrations that match or exceed those measured in soils after standard field applications of the herbicide. The isolates not only survived but continued to proliferate, and in some cases displayed heightened tolerance to beta‑lactam, fluoroquinolone and aminoglycoside antibiotics after glyphosate exposure.
The lead author, identified only in a Science Daily press release, described glyphosate as acting “as a selective pressure, similar to antibiotics, that favors the emergence and maintenance of multidrug‑resistant organisms.” The study’s findings were posted on a pre‑print server and highlighted by Science Daily on June 20, 2026.
Why it matters
AMR is already a global health emergency, responsible for an estimated 1.27 million deaths in 2022, according to the World Health Organization. The conventional narrative places the primary drivers of resistance in clinical misuse of antibiotics and, to a lesser extent, in animal‑farm antibiotic use. If a non‑antibiotic chemical such as glyphosate can also select for resistant bacteria, the scope of the problem widens dramatically.
Glyphosate is applied to an estimated 750 million acres of cropland worldwide each year, making it the most heavily used herbicide on the planet. Residues routinely appear in surface water, groundwater and soils adjacent to treated fields. Should those residues enable superbugs to persist outside hospital walls, the line between “clinical” and “environmental” AMR reservoirs could blur, complicating containment strategies that currently focus on stewardship within healthcare settings.
Background and context
Glyphosate’s safety profile has been debated for over two decades, with the most prominent controversy centering on its potential carcinogenicity. Regulatory agencies in the United States, European Union and many other jurisdictions have concluded that the chemical is unlikely to cause cancer at typical exposure levels, while some courts and independent scientists have reached opposite conclusions.
The new study adds a different dimension to the debate by linking glyphosate to bacterial stress responses. Prior research has shown that sub‑lethal concentrations of certain biocides, such as triclosan and chlorhexidine, can co‑select for antibiotic resistance by activating efflux pumps and other defense mechanisms. Glyphosate’s mode of action—blocking the shikimate pathway in plants and some microbes—has not previously been implicated in such cross‑resistance, making the current findings noteworthy.
Competing claims and uncertainty
The authors caution that their work is limited to in‑vitro experiments. “Laboratory conditions cannot fully replicate the complex interactions in soil ecosystems,” the press release notes. Critics point out that glyphosate rapidly binds to soil particles and is degraded by microbial activity, potentially reducing its bioavailability in the field.
Environmental microbiologists not involved in the study have called for field‑based investigations to measure actual glyphosate concentrations in soils where resistant bacteria have been isolated, and to assess whether the observed laboratory tolerance translates into real‑world persistence. Some agricultural groups argue that the study’s glyphosate concentrations exceed typical field residues, and that the bacteria tested were already highly resistant, possibly skewing results.
Regulatory agencies have not yet commented on the study. The U.S. Environmental Protection Agency (EPA) and the European Food Safety Authority (EFSA) typically require extensive field data before amending pesticide risk assessments, and both have previously concluded that glyphosate poses low risk to human health at current usage rates.
What to watch next
The research team plans to conduct soil microcosm experiments that simulate realistic field conditions, including the presence of native microbial communities and fluctuating moisture levels. Funding for such studies may come from national science agencies or from independent foundations focused on AMR.
In parallel, public health agencies are expected to evaluate whether existing AMR surveillance programs should incorporate environmental sampling of herbicide‑treated sites. The World Health Organization’s Global Antimicrobial Resistance Surveillance System (GLASS) has recently expressed interest in “One Health” approaches that integrate human, animal and environmental data.
Legislators in several countries, including the United States, Canada and members of the European Parliament, have introduced bills to increase oversight of pesticide impacts on microbial ecosystems. The outcome of those proposals could shape future regulatory frameworks for glyphosate and other agrochemicals.
Conclusion
The discovery that hospital‑derived superbugs can thrive in glyphosate‑containing environments raises a flag for policymakers, scientists and the public alike. While the findings are preliminary and confined to laboratory settings, they underscore the need to view antimicrobial resistance through a broader ecological lens. If subsequent field studies confirm that glyphosate residues help sustain or spread resistant bacteria, the implications could reach far beyond the ongoing debates over the herbicide’s carcinogenic potential, prompting a reassessment of how agricultural chemicals intersect with global health threats.
Sources
Science Daily, “One of the world’s most popular weedkillers may be fueling deadly superbugs,” June 20 2026, https://www.sciencedaily.com/releases/2026/06/260620100434.htm
Source: Science Daily – Original article
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Story synopsis gathered from: Science Daily — source
