One of the world’s most popular weedkillers may be fueling deadly superbugs

New Delhi, India Jul 3, 2026 ALN: Antimicrobial resistance (AMR) is a critical public issue, contributing to an estimated 1.1 million to 1.4 million deaths worldwide each year. This growing threat is most commonly associated with the overuse and misuse of antibiotics, which has led to the emergence of bacteria that are resistant to multiple drugs. However, new research suggests that the problem may be exacerbated by the use of certain herbicides, particularly glyphosate, which is one of the most widely used weedkillers globally.

Glyphosate, the active ingredient in many herbicides, including the well-known Roundup, has been under scrutiny for its potential effects on human and the environment. The herbicide was first registered in the United States in 1974 and has since become a staple in agricultural practices due to its effectiveness in controlling a wide range of weeds. However, the implications of its widespread use are becoming increasingly apparent, particularly in relation to antimicrobial resistance.

In a study led by Dr. Daniela Centrón from the Institute of Medical Microbiology and Parasitology in Buenos Aires, researchers found compelling evidence that glyphosate may contribute to the selection of bacteria that are resistant to multiple antibiotics. This raises concerns about the unintended consequences of herbicide application in agricultural environments, where glyphosate is commonly used.

Dr. Centrón and her colleagues analyzed 68 bacterial strains collected from a protected nature reserve in the Paraná delta, a wetland region north of Buenos Aires, between 2018 and 2020. Notably, glyphosate has never been applied within the reserve, yet the researchers found that the bacteria present there exhibited resistance to glyphosate and various antibiotics. This finding suggests that glyphosate may be influencing bacterial communities even in areas where it is not directly used.

To better understand the relationship between glyphosate and antimicrobial resistance, the researchers tested the bacterial strains for resistance to 16 commonly used antibiotics, including ampicillin, meropenem, tetracycline, and vancomycin. They also assessed the strains' resistance to pure glyphosate and glyphosate-based herbicides. The results were alarming, particularly when compared to bacterial strains obtained from local hospitals, which included multidrug-resistant species.

The hospital strains exhibited widespread antimicrobial resistance, with individual strains resistant to between one and 16 of the antibiotics tested. Most concerning was the finding that 74% of these hospital strains were resistant to carbapenems, a class of broad-spectrum antibiotics often reserved for last-resort treatment of serious infections. Notably, all of the hospital-derived strains also demonstrated high resistance to glyphosate, indicating a potential link between the two forms of resistance.

Dr. Camila Knecht, the first author of the study, highlighted the implications of these findings, noting that if these resistant bacteria enter the environment through untreated wastewater from hospitals, they could thrive in agricultural areas where glyphosate is applied. This scenario raises significant public concerns, as it suggests that agricultural practices may inadvertently contribute to the spread of antibiotic-resistant bacteria.

In addition to the hospital strains, the researchers collected 68 strains from the Paraná delta, which represented 15 different genera, including Acinetobacter, Pseudomonas, Exiguobacterium, and Chryseobacterium. Remarkably, every strain displayed some level of resistance to glyphosate and glyphosate-based herbicides, despite the absence of these chemicals in the reserve itself. Among these environmental strains, Enterobacter species showed the highest tolerance to glyphosate, surviving concentrations of up to 80 milligrams per milliliter, while Bacillus species were particularly sensitive, with growth inhibited at concentrations as low as 2.5 milligrams per milliliter.

The researchers also constructed a genetic "family tree" of the 102 bacterial strains included in the study, revealing that bacteria with the highest glyphosate resistance were often closely related, irrespective of their origin—whether from hospitals, farms, or the Paraná delta. This suggests that glyphosate resistance can spread between different environments, creating a complex web of resistance that poses challenges for public .

Dr. Jochen A Müller, a coauthor of the study, concluded that the use of glyphosate in the environment can lead to the evolution of resistant bacteria in impacted soils, while antibiotic use in hospitals drives resistance in clinical settings. The water cycle plays a crucial role in the transmission of these bacteria between agricultural and hospital environments, further complicating efforts to combat AMR.

The implications of these findings extend beyond the laboratory, as glyphosate has long been a subject of scientific and regulatory debate. Research has shown that glyphosate can harm non-target organisms, particularly arthropods such as bees, and the International Agency for Research on Cancer has classified it as a probable human carcinogen. In light of these concerns, several European countries have taken steps to restrict the use of glyphosate. For instance, France, Belgium, and the Netherlands have banned glyphosate for household applications, while Germany prohibits its use in public spaces.

Given the potential link between glyphosate use and antimicrobial resistance, the researchers advocate for a reevaluation of pesticide regulations. They argue that policies governing the use of any pesticide should consider the potential for co-selection of antibiotic resistance before products reach the market. This includes mandating testing for antibiotic resistance in conjunction with glyphosate use and requiring labels to warn of the potential for antibiotic resistance genes to spread from glyphosate-contaminated soils to hospital environments through untreated wastewater.

As the world grapples with the dual challenges of food production and public , the findings of this study underscore the need for a more integrated approach to managing agricultural practices and addressing antimicrobial resistance. As research continues to evolve, it is crucial for policymakers, researchers, and care professionals to work collaboratively to mitigate the risks associated with both glyphosate use and antibiotic resistance, ensuring a safer and ier future for all.