Dissemination of antibiotic resistance genes through soil-plant-earthworm continuum in the food production environment

[Display omitted] •The role of antibiotics on antimicrobial resistance development in irrigated agricultural microbiomes was quantified.•Irrigation of spinach and radish with treated municipal wastewater containing antibiotics led to ARG enrichment.•Spinach was more susceptible to the enrichment of antibiotic resistance genes than was radish.•ARB genomes were recovered from earthworm feces fed with plants irrigated with treated municipal wastewater. Treated municipal wastewater (TMW) can provide a reliable source of irrigation water for crops, which is especially important in arid areas where water resources are limited or prone to drought. Nonetheless, TMW may contain residual antibiotics, potentially exposing the crops to these substances. The goal of this study was to investigate the dissemination of antibiotics resistance genes (ARGs) in the soil–plant–earthworm continuum after irrigation of spinach and radish plants with TMW containing trimethoprim, sulfamethoxazole, and sulfapyridine in a greenhouse experiment, followed by feeding of earthworms with harvested plant materials. Our results showed that antibiotic resistance genes (ARGs) were enriched in the soil–plant–earthworm microbiomes irrigated with TMW and TMW spiked with higher concentrations of antibiotics. The number of ARGs and antibiotic-resistant bacteria (ARB) enrichment varied with plant type, with spinach harboring a significantly higher amount of ARGs and ARB compared to radish. Our data showed that bulk and rhizosphere soils of spinach and radish plants irrigated with MilliQ water, TMW, TMW10, or TMW100 had significant differences in bacterial community (p