摘要

      为了降低健康风险，需要有效的治疗方法去除饮用水中的抗药性细菌（ARB）和抗药性基因（ARGs）。然而，在传统的水消毒过程中，对ARB和ARG的去除缺乏经验数据。本研究以大肠杆菌和粪肠球菌为载体，采用三种消毒方法（氯化、臭氧氧化和紫外线处理）去除ARB和ARGs。细菌灭活采用平板计数法，ARG损伤采用实时PCR定量。仅在臭氧处理中，当使用1 mg*L-1臭氧，接触时间为5分钟时，细菌细胞和ARGs的失活率相似，导致细菌细胞减少5.0对数，ARGs减少4.3-4.6对数。对于氯和紫外线，在较低的剂量下观察到细菌细胞的灭活，而不是减少ARG拷贝数所需的灭活。使用0.5 mg*L-1游离氯（30分钟接触时间）可使细菌数量减少3.8-5.6对数，ARGs减少0.8-2.8对数。600j*m-2紫外光照射可使细菌细胞减少4.8-5.5log，但ARGs的减少（0-1.0log）可忽略不计。虽然紫外线和氯处理对细菌细胞的灭活是有效的，但ARGs的降解是不完全的。因此，即使在消毒过程中，质粒携带的ARGs也可能被转移到其他细菌中。我们的研究结果对饮用水消毒过程中ARGs的去向提供了重要的见解。

       Efficient treatment methods for the removal of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) from drinking water are needed to reduce health risks. However, there is a lack of empirical data on ARB and ARG removal during conventional water disinfection processes. In this study, the removal of ARB and ARGs by three disinfection processes (chlorination, ozonation, and UV treatment) was investigated on a laboratory scale using Escherichia coli and Enterococcus faecium carrying ARGs. Bacterial inactivation was determined by plate count methods, and ARG damage was quantified using real-time PCR. Only for ozone treatment, similar inactivation rates for bacterial cells and ARGs were observed when 1 mg*L^-1 of ozone, with a contact time of 5 min, was used, which resulted in a 5.0 log reduction of bacterial cells and a 4.3-4.6 log reduction of ARGs. For chlorine and UV, inactivation of bacterial cells was observed at lower doses than those needed for the decrease of ARG copy numbers. The use of 0.5 mg*L^-1 free chlorine (30 min contact time) led to a 3.8-5.6 log reduction of the bacterial numbers and to a 0.8-2.8 log reduction of ARGs. Ultraviolet light irradiation with 600 J*m^-2 resulted in a 4.8-5.5 log reduction of bacterial cells, but in a negligible reduction (0-1.0 log) of ARGs. Although UV and chlorine treatments were effective in the inactivation of bacterial cells, incomplete degradation of ARGs was observed. Therefore, plasmid-borne ARGs can potentially be transferred to other bacteria even after the disinfection process. Our results provide important insights into the fate of ARGs during drinking water disinfection processes.

       https://www.sciencedirect.com/science/article/abs/pii/S1438463918309593?via%3Dihub