Sulfur-induced oxidative stress enhances horizontal transfer of antibiotic resistance genes

Environmental factors play a crucial role in the dissemination of antibiotic resistance genes (ARGs); however, the effects of sulfur species in high-sulfur environments remain poorly understood. This study investigated the impact of elemental sulfur and sulfate on horizontal ARG transfer between Escherichia coli and Pseudomonas aeruginosa . Results showed that both sulfur forms significantly enhanced ARG dissemination, particularly through conjugation and transformation processes. Increased reactive oxygen species (ROS) production and oxidative stress responses were observed under sulfur exposure, accompanied by elevated membrane permeability and enhanced release of intracellular genetic materials. Transcriptomic analysis further revealed the upregulation of genes associated with lipopolysaccharide biosynthesis and glutathione metabolism, suggesting coordinated responses involving membrane remodeling and cellular redox regulation. Overall, these results indicate that sulfur-induced oxidative stress may be an important factor promoting ARG dissemination in sulfur-enriched environments, highlighting potential ecological risks in mining-impacted agricultural and aquaculture systems.