Selection for resistance to a glyphosate-containing herbicide in Salmonella enterica does not result in a sustained activation of the tolerance response or increased cross-tolerance and cross-resistance to clinically important antibiotics.

In this study, we investigated whether a chronic exposure to a glyphosate-containing herbicide (GBH) results in resistance, a constitutive activation of the tolerance and stress response and cross-tolerance or cross-resistance to antibiotics. Of the ten farm animals-derived clinical isolates of Salmonella enterica subjected to experimental evolution in increasing concentrations of GBH, three isolates showed a stable resistance with mutations associated with the glyphosate target gene aroA and no fitness costs. The global quantitative proteomics analysis demonstrated activation of the cellular tolerance and stress response during the transient exposure to GBH, but not constitutively in the resistant mutants. Resistant mutants displayed no cross-resistance or cross-tolerance to antibiotics. These results suggest that while transient exposure to GBH triggers cellular tolerance response in Salmonella enterica, this response does not become genetically fixed after selection for resistance to GBH and does not result in increased cross-tolerance or cross-resistance to clinically important antibiotics under our experimental conditions.ImportanceGlyphosate-based herbicides (GBH) are among the world's most popular, with traces commonly found in food, feed and the environment. Such high ubiquity means that the herbicide may come into contact with various microorganisms, on which it acts as an antimicrobial and may select for resistance and cross-resistance to clinically important antibi...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research