摘要

       本研究的目的是使用模拟生物膜反应器全面了解来自饮用水分配管道的多相样品中抗生素抗性基因 (ARG) 的特征。在连续运行 120 天期间，研究了反应器中三相（水、颗粒和生物膜）样品中的常见参数和 6 个 ARG（ermA、ermB、aphA2、ampC、sulII 和 tetO），证明了二次污染ARGs。反应器流出物中6种ARGs的丰度逐渐增加，120d流出物中aphA2和sulII的相对丰度最高，分别为9.9×10-4和1.3×10-3，增加了1.5倍和进水相比增加了 2.8 倍。生物膜相中 6 个 ARG 的相对丰度在 120 d 时显着增加（P < 0.05），这是由于生物膜中的健壮细菌在大块老化生物膜脱离后新暴露所致。在粒子阶段，四个 ARG 在 120d 期间没有显着变化。三相样品中的6个ARGs与管水中余氯呈负相关，说明三相样品中ARGs的低丰度与余氯的改善有关。可培养细菌的比例表明，健壮和活跃的细菌与生物膜中的 6 个 ARG 呈负相关。管道中的总有机碳 (TOC) 与水相和生物膜相中可培养细菌的比例呈正相关，这表明管道中 TOC 的减少导致 ARG 丰度低。在20mJ/cm2的低压紫外线（LP-UV）照射下，三相样品中的ARGs得到有效控制，表明LP-UV可用于末端水中的ARG去除，对管道出水进行补充杀菌处理.

       The aim of this study was to gain comprehensive insights into the characteristics of antibiotic resistance genes (ARGs) in multiphase samples from drinking water distribution pipelines using a simulated biofilm reactor. During 120 d of continuous operation, common parameters and six ARGs (ermA, ermB, aphA2, ampC, sulII, and tetO) in samples of three phases (water, particle, and biofilm) from the reactor were investigated, which demonstrated secondary contamination by ARGs. Abundances of the six ARGs in the reactor effluent increased gradually, and in the 120 d effluent, the relative abundances of aphA2 and sulII were the highest, at 9.9 × 10−4 and 1.3 × 10−3, respectively, with a 1.5-fold and 2.8-fold increase, compared with those in the influent. The relative abundances of the six ARGs in the biofilm phase increased significantly (P < 0.05) at 120 d, which was caused by robust bacteria in biofilm that was newly exposed following the detachment of a large piece of aging biofilm. In the particle phase, four of the ARGs did not change significantly during the 120 d period. The six ARGs in the samples of three phases showed a negative correlation with residual chlorine in the pipe water, which demonstrated that low abundance of ARGs in the samples of three phases was related to the improvement of residual chlorine. The proportion of cultivable bacteria illustrated that the robust and active bacteria were negatively correlated with the six ARGs in the biofilm. Total organic carbon (TOC) in the pipeline showed a positive correlation with the proportion of cultivable bacteria in both the water and biofilm phases, which indicated that a TOC reduction in the pipeline contributed to low abundance of ARGs. With low-pressure ultraviolet (LP-UV) irradiation of 20 mJ/cm2, ARGs in the samples of three phases were efficiently controlled, which showed that LP-UV can be used for ARG removal in terminal water for supplemental bactericidal treatment of pipeline effluent.

https://www.sciencedirect.com/science/article/abs/pii/S0048969718332686