摘要
      抗生素抗性细菌（ARB）和抗生素抗性基因（ARGs）作为新出现的污染物，被释放到环境中，增加了水平基因转移（HGT）的风险。然而，数量有限的研究量化了ARB消毒对HGT风险的影响。本研究使用电化学流通反应器（EFTR）研究了大肠杆菌10667（sul）的失活以及ARGs的释放和去除。此外，以无抗性大肠杆菌GMCC 13373为受体，携带质粒RP4的大肠杆菌DH5α为供体，探讨了消毒后HGT的转移频率和潜在机制。观察到电流密度阈值（0.25mA/cm2）破坏细胞并释放细胞内ARG（iARGs）以增加细胞外ARG（eARGs）浓度。电流密度进一步增加到1mA/cm2导致eARGs浓度下降，这是由于eARGs的降解速率高于iARGs的释放速率。将EFTR对ARGs的降解性能和HGT频率与传统消毒工艺（包括氯化和紫外线辐射）进行了比较。与氯化（10.23%）和紫外线（27.07%）相比，EFTR观察到更高的ARGs降解率（83.46%）。因此，EFTR降低了释放到受体（正向转移）的ARGsHGT频率（0.69），并且该值低于氯化（2.69）和紫外线的值（1.73）。同时，通过质粒RP4从供体（反向转移）转移存活的损伤的细胞通透性增加的大肠杆菌10667（sul），与氯化（0.26）和紫外线（0.16）相比，通过EFTR的频率更高，为0.33。此外，sul3基因比sul1和sul2基因对EFTR的抗性最小。这些发现为受伤的大肠杆菌10667（sul）和环境细菌之间的HGT机制提供了重要的见解。EFTR是一种很有前途的防止抗生素耐药性传播的消毒技术。
ABSTRACT
Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs), as emerging pollutants, are released into environment, increasing the risk of horizontal gene transfer (HGT). However, a limited number of studies quantified the effects of ARB disinfection on the HGT risk. This study investigated the inactivation of E. coli 10667 (sul) and the release and removal of ARGs using an electrochemical flow-through reactor (EFTR). Furthermore, the transfer frequencies and potential mechanisms of HGT after disinfection were explored using non-resistant E. coli GMCC 13373 as the recipient and E. coli DH5α carrying plasmid RP4 as the donor. A threshold of current density (0.25 mA/cm2) was observed to destroy cells and release intracellular ARGs (iARGs) to increase extracellular ARGs (eARGs) concentration. The further increase in the current density to 1 mA/cm2 resulted in the decline of eARGs concentration due to the higher degradation rate of eARGs than the release rate of iARGs. The performance of ARGs degradation and HGT frequency by EFTR were compared with those of conventional disinfection processes, including chlorination and ultraviolet radiation (UV). A higher ARGs degradation (83.46%) was observed by EFTR compared with that under chlorination (10.23%) and UV (27.07%). Accordingly, EFTR reduced the HGT frequency (0.69) of released ARGs into the recipient (Forward transfer), and the value was lower than that by chlorination (2.69) and UV (1.73). Meanwhile, the surviving injured E. coli 10667 (sul) with increased cell permeability was transferred by plasmid RP4 from the donor (Reverse transfer) with a higher frequency of 0.33 by EFTR compared with that under chlorination (0.26) and UV (0.16). In addition, the sul3 gene was the least resistant to EFTR than sul1 and sul2 gene. These findings provide important insights into the mechanism of HGT between the injured E. coli 10667 (sul) and environmental bacteria. EFTR is a promising disinfection technology for preventing the spread of antibiotic resistance.

https://www.sciencedirect.com/science/article/abs/pii/S0043135422000537