IMPACT OF GLYPHOSATE HERBICIDES ON PREVALENCE OF ANTIMICROBIAL RESISTANCE IN SOILS FROM ARGENTINA

C. KNECHT; B. PRACK MC CORMICK; N. DONIS ; J. FUCHS 3 ; M. QUIROGA 1 ; D. CENTRÓN

Virtual

Congreso; Microbiological adaptation in times of ecological disturbance and disruption; 2022

International Union of Microbiological Societies

Background and Aims To unveil the mechanisms that affect antimicrobial resistance (AMR) in the environment is crucial because environmental bacterial communities are the source of antibiotic resistance genes subsequently detected inhospitals. Glyphosate inhibits the shikimate pathway, which is necessary for the synthesis of aromatic amino acids in plants but also in bacteria. Glyphosate could exert a selective pressure on bacteria, favouringtolerant/resistant strains in the environment. Because one microorganism can carry several AMR genes (ARG), our working hypothesis is that the intensive use of glyphosate herbicides is a driving factor for the development and spread of AMR in the environment. Our aim was to analyse glyphosate and AMR strains in environmentalsamples and compare them with clinical isolates.Methods We isolated bacterial strains from one site at the Paraná river (Argentina) in an area with high concentrations of glyphosate and tested them for their tolerance towards glyphosate, a glyphosate-containing herbicide, andantibiotics. Isolates were identified by sequencing of their 16S rRNA gene. Same procedure was carried out with clinical isolates.Results Bacteria showed concentration-dependent and differential susceptibility to glyphosate and its commercial formulation. The isolates that were tolerant to the highest glyphosate concentrations were also resistant to several classes of antimicrobials. Enterobacter cloacae Complex and Serratia marcescens which are critical in the local hospital environment tolerated the highest concentration of herbicide.ConclusionsUnderstanding the mechanisms of the interrelationship between herbicide resistance and AMR, as well as the epidemiology of AMR related to  herbicide use, is fundamental to develop guidelines for the rational use ofherbicides.