Chen Aoxi, Liu Kunyu, Wu Xin, Qi Tianle, Lv Zhi, Lu Yi, Tao Yang, Liu Cuiyun
College of Urban Construction, Nanjing Tech University, Nanjing, China.
Jiangsu Key Laboratory of Industrial Water-Conservation & Emission Reduction, Nanjing Tech University, Nanjing, China.
Water Environ Res. 2025 Jul;97(7):e70155. doi: 10.1002/wer.70155.
Antibiotics and heavy metals can accumulate in wastewater pipe, and they could affect the proliferation of resistance genes in pipe. This study investigated the effects of tetracycline (TC) and Cu stress on extracellular polymeric substances (EPS) of sediments and the proliferation process and mechanism of typical antibiotic resistance genes (ARGs) and heavy metal resistance genes (HMRGs) in pipe. The results showed that TC and Cu induced microorganisms to secrete more tightly bound EPS (TB-EPS) in sediments. Under the 20 days exposure of 10,000 μg/L TC, TB-EPS increased by 49.38% compared with that without TC. Under TC and Cu stress, microorganisms secreted more functional groups associated with proteins and polysaccharides, and the secondary structure of proteins (α-helix and β-sheet) was changed, which improved the stability and aggregation of cell structure. Under the single and combined stress of TC and Cu, the relative abundance of most resistance genes in the sediment of wastewater pipe increased significantly (p ≤ 0.05). And TC and Cu stress increased the abundance of genes encoding for efflux pumps (tet(A), tet(G), copA, and copB) and promoted intl1-mediated horizontal gene transfer. This study could provide the theoretical basis for reducing the further spread of resistance genes in wastewater pipe.
抗生素和重金属会在污水管道中积累，并且它们会影响管道中抗性基因的增殖。本研究调查了四环素（TC）和铜胁迫对沉积物胞外聚合物（EPS）的影响以及管道中典型抗生素抗性基因（ARGs）和重金属抗性基因（HMRGs）的增殖过程及机制。结果表明，TC和铜诱导微生物在沉积物中分泌更多紧密结合的EPS（TB-EPS）。在10000μg/L TC暴露20天的情况下，与无TC相比，TB-EPS增加了49.38%。在TC和铜胁迫下，微生物分泌更多与蛋白质和多糖相关的官能团，并且蛋白质的二级结构（α-螺旋和β-折叠）发生改变，这提高了细胞结构的稳定性和聚集性。在TC和铜的单一及复合胁迫下，污水管道沉积物中大多数抗性基因的相对丰度显著增加（p≤0.05）。并且TC和铜胁迫增加了编码外排泵的基因（tet(A)、tet(G)、copA和copB）的丰度，并促进了intl1介导的水平基因转移。本研究可为减少抗性基因在污水管道中的进一步传播提供理论依据。
