https://phys.org/news/2026-03-agricultural-soils-exposed-controversial-weedkiller.
Agricultural soils exposed to controversial weedkiller may be unexpected breeding ground for hospital ‘superbugs’
Each year, antimicrobial resistance (AMR) is responsible for an estimated 1.1 to 1.4 million deaths worldwide. Now, scientists have found evidence that the spread of AMR isn’t always driven by bacteria evolving to resist the antibiotics themselves: rather, certain weedkillers can have the same effect.
“Here we show that the most common species of multidrug-resistant bacteria from hospitals are not only resistant to multiple antibiotic classes, but also to high concentrations of the weedkiller glyphosate,” said Dr. Daniela Centrón, a researcher at the Institute of Medical Microbiology and Parasitology in Buenos Aires and the senior author of the study in Frontiers in Microbiology.
“These results suggest that weedkillers—which, unlike antibiotics, are widely applied in agricultural environments—may have the unintended side effect of selecting for AMR among bacterial communities within the soil.” (See link for article)
https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2026.1740431/full
Glyphosate resistance as a potential driver for the dissemination of multidrug-resistant clinical strains
Camila A. Knecht 1,2 Barbara Prack McCormick 1,2,3 Verónica E. Álvarez 1,2 Adrián Gonzales Machuca 1,2 Fernanda Buzzola 3,4 Julio Fuchs 5 Pablo Salgado 6 Josefina Campos 7,8 Daniela Centrón 1,2*
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1. Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina. Universidad de Buenos Aires, Buenos Aires, Argentina
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2. Laboratorio de Investigaciones en Mecanismos de Resistencia a Antibióticos (LIMRA), Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM), CONICET – Universidad de Buenos Aires, Buenos Aires, Argentina
Abstract
The rise of antimicrobial resistance (AMR) constitutes a serious threat to global health. Environmental bacterial communities are a key reservoir of AMR genes (ARGs) that can spread to clinical pathogens. Biocides, which include broad-spectrum herbicides, can co-select for ARGs, posing a potential driver for AMR spread. Glyphosate, the world’s most widely used herbicide with known bactericidal properties, targets the shikimate pathway and may thus exert selective pressure favoring resistant bacteria, potentially elevating clinical AMR risk from a One Health perspective. We assessed glyphosate resistance in multidrug-resistant (MDR) species isolated from nosocomial infections. Furthermore, we investigated the relationship between glyphosate-resistant environmental species and clinically relevant MDR pathogens using whole-genome sequencing of environmental and clinical strains. Multidrug-resistant species from hospital-acquired infections exhibited high levels of glyphosate resistance. We established a link between glyphosate-resistant environmental species and typically MDR species common in nosocomial settings. Genomic analysis revealed that glyphosate resistance is partially independent of mutations in the target enzyme (5-enolpyruvylshikimate-3-phosphate synthase), suggesting the contribution of alternative mechanisms, such as efflux pumps. Our findings indicate that glyphosate exposure could favor the prevalence of bacteria associated with nosocomial infections and the rise of MDR clinical strains. This suggests that intensive glyphosate use may accelerate the dissemination of AMR. Consequently, the AMR dimension should be incorporated into the environmental risk assessment of biocidal products that are not used as antimicrobial agents.
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