The fates of antibiotic resistance genes and their association with cell membrane permeability in response to peroxydisulfate during composting

Abstract

The aims of this study were to use metagenomics to reveal the fates of antibiotic resistance genes (ARGs) during composting under the regulation of peroxydisulfate and clarify the relationship between ARGs and cell membrane permeability. Results showed that peroxydisulfate increased cell membrane permeability by effectively regulating the expression of outer membrane protein and lipopolysaccharide related genes. Besides, it reduced polysaccharides and proteins in extracellular polymer substances by 36% and 58%, respectively, making it easier for intracellular ARGs (i-ARGs) to reach the extracellular environment, among which the absolute intracellular abundance of mphK, Erm(31), and tet(44) decreased to 1.2, 1.0, and 0.89 fold of the control, respectively. Finally, variation partitioning analysis showed that i-ARGs dominated the removal of ARGs. These results revealed that the removal of i-ARGs by activated peroxydisulfate was the key to the removal of ARGs and increased cell membrane permeability played a key role for peroxydisulfate to remove i-ARGs during composting.