On the eve of the review of the European authorization of glyphosate (due to expire Dec. 15.22), a scientific study published in Scientific Reports highlights the role of the most widely used herbicide molecule in promoting antibiotic resistance of lethal bacteria spread in hospitals. (1)
It is useful to remember that antibiotic ineffectiveness (antimicrobial resistance) is called the ‘silent epidemic’ by the WHO, which already claims 700,000 lives each year and could cause 10 million deaths a year by 2050. (2)
Glyphosate and antibiotic resistance
The use of glyphosate has been associated with several serious adverse effects (cytotoxicity, carcinogenicity, teratogenicity, endocrine disruption, metabolic alterations) even at exposures below environmentally relevant concentrations or recommended doses for use in agriculture and horticulture, the Hungarian researchers recall. Nevertheless, the molecule continues to infest the soil, at the rate of 700 thousand tons per year.
A lesser-known nefarious effect of glyphosate is the promotion of antibiotic resistance. Together with dicamba (an agrotoxic banned in the EU, where it is nonetheless produced), Bayer-Monsanto’s molecule had already been found to create antibiotic resistance in Salmonella and E.coli. (3)
For the first time, the study under review shows that glyphosate also potentiates Pseudomonas aeruginosa, the super-bacterium that causes deadly hospital infections, making it resistant even to the antibiotic ipenem, which is administered intravenously in hospitals for serious infections. (4)
The study
The researchers analyzed five different strains of P. aeruginosa, four recovered from the environment and one from a clinical setting. All were initially sensitive to antibiotics.
To test The impact of glyphosate and formulations containing it (such as Roundup Mega, Dominator Extra 608 SL, Gladiator 480 SL, etc.), P. aeruginosa was exposed to a concentration of the herbicide (0.5 percent) equal to the recommended dilution in agricultural and household products and similar to those found in water after agricultural practices.
Exposure of the bacterium to the molecule resulted in reduced sensitivity to imipenem, while other carbapenem antibiotics (doripenem and meropenem) maintained their efficacy.
Notes
(1) Háhn, J., Kriszt, B., Tóth, G. et al. Glyphosate and glyphosate-based herbicides (GBHs) induce phenotypic imipenem resistance in Pseudomonas aeruginosa. Sci Rep 12, 18258 (2022). https://doi.org/10.1038/s41598-022-23117-9
(2) Choudhury S, Medina-Lara A, Smith R. Antimicrobial resistance and the COVID-19 pandemic.. Bull World Health Organ. 2022 May 1;100(5):295-295A. doi: 10.2471/BLT.21.287752. PMID: 35521033; PMCID: PMC9047431.
(3) Brigitta Kurenbach, Delphine Marjoshi, Carlos F. Amábile-Cuevas, Gayle C. Ferguson, William Godsoe, Paddy Gibson, Jack A. Heinemann. Sublethal Exposure to Commercial Formulations of the Herbicides Dicamba, 2,4-Dichlorophenoxyacetic Acid, and Glyphosate Cause Changes in Antibiotic Susceptibility in Escherichia coli and Salmonella enterica serovar Typhimurium. AMS Journal. 2015. https://doi.org/10.1128/mBio.00009-15
(4) ‘Imipenem is a member of the Carbapenem family, natural and synthetic beta-lactam antibiotics that exhibit a broad spectrum of antibacterial action and are active on methicillin-sensitive Gram-positive bacteria, most Gram-negatives (including Pseudomonas spp.) and anaerobes. They are drugs that are structurally similar to penicillins and cephalosporins and have the same mechanism of action: they inhibit bacterial growth by interfering with bacterial wall synthesis. In addition to Imipenem, which is the most effective, Tienamycin and Meropenem also belong to this group‘. V. Humanitas https://www.humanitas.it/enciclopedia/principi-attivi/antibiotici/imipenem/
Professional journalist since January 1995, he has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic surveys on food, she has published the book "Reading labels to know what we eat".
