A critical review of antibiotic resistance genes transmission driven by non-antibiotic pollutants: roles and molecular mechanisms

The extensive use of antibiotics causes the abundant antibiotic residuals in the environment, further accelerating the transfer of antibiotic resistance genes (ARGs). ARGs pose a high risk to public health and environmental ecosystems. Pollutants and ARGs coexist in various environments such as livestock farms, landfills, constructed wetlands, etc. As a sink of various pollutants, wastewater treatment plants cannot completely remove antibiotics and ARGs, as well as provide a habitat for ARGs accumulation and transfer. In addition to antibiotics, numerous non-antibiotic pollutants, such as nanomaterials, disinfectants, non-antibiotic pharmaceuticals and microplastics, have also been reported to drive ARGs dissemination, especially their conjugative transfer. These non-antibiotic pollutants could induce bacterial oxidative stress, redistribute energy for metabolic pathways and upregulate the expression of plasmid-related genes. To fully understand the fate and risk of ARGs in ecosystems, it remains urgent to emphasize and fill the gap in the role and mechanism of non-antibiotic pollutants in facilitating ARGs transfer. Therefore, this review systematically summarizes the contribution of non-antibiotic pollutants to the accumulation and spread of ARGs and their regulatory mechanisms. More efforts could be paid to microbial behaviors and interactions under the stress of multiple non-antibiotic pollutants. It provides a holistic insight into the potential ecological risks of non-antibiotic pollutants and their resulting ARGs transfer, which probably facilitates the development of effective control strategies for resistance.