摘要

       城市污水处理系统是抗生素耐药基因（ARGs）在人类和自然环境中的主要传播节点。本研究探讨了在光生物反应器中抗生素抗性基因和1-3类整合子整合酶基因在湖泊或自来水稀释（70/30）的城市污水中的去向。采用亚基因组和定量分析相结合的方法。光生物反应器处理城市污水导致细菌群落中抗药性比例降低，ARG亚型数量减少，个体ARG丰度降低。光生物反应器排放的ARGs和intI1基因丰度及相对丰度与常规污水处理厂排放的ARGs和intI1基因丰度相当或低于各自的值。抗性的降低与废水处理过程中细菌群落组成的变化密切相关，因为它是对藻类强烈生长引起的pH值升高的响应。一些细菌属（如偶氮菌属、十二氯单胞菌属和磺脲类）被认为是多种耐药类型的潜在宿主。尽管湖水为处理系统提供了多样且丰富的抗性和intI基因图谱，但事实证明，湖水比自来水更有利于废水稀释。抗生素耐药性的多样性（检测到的耐药类型和亚型的数量）和比例，质粒携带的整合子整合酶基因的读取量，以及大多数定量ARGs（aadA，sul1，tetQ，tetW，qnrS，ermB，在利用湖水稀释废水的光生物反应器中，blaOXA2型和intI1基因以及多抗性决定因子的数量显著降低。

      Wastewater treatment systems receiving municipal wastewater are major dissemination nodes of antibiotic resistance genes (ARGs) between anthropogenic and natural environments. This study examined the fate of antibiotic resistome and class 1-3 integron-integrase genes in photobioreactors that were treating municipal wastewater diluted (70/30) with lake or tap water for the algal biomass production. A combined approach of metagenomic and quantitative (qPCR) analysis was undertaken. Municipal wastewater treatment in the photobioreactors led to reduced antibiotic resistome proportion, number of ARG subtypes, and abundances of individual ARGs in the bacterial community. The ARGs and intI1 gene abundances and relative abundances in the discharges of the photobioreactors were either comparable or lower than the respective values in the effluents of conventional wastewater treatment plants. The reduction of the resistome proved to be strongly related to the changes in the bacterial community composition during the wastewater treatment process as it was responding to rising pH levels caused by intense algal growth. Several bacterial genera (e.g., Azoarcus, Dechloromonas, and Sulfuritalea) were recognized as potential hosts of multiple antibiotic resistance types. Although the lake water contributed a diverse and abundant resistome and intI genes profile to the treatment system, it proved to be considerably more beneficial for wastewater dilution than the tap water. The diversity (number of detected resistance types and subtypes) and proportion of the antibiotic resistome, the amount of plasmid borne integron-integrase gene reads, and the abundances and relative abundances of the majority of quantified ARGs (aadA, sul1, tetQ, tetW, qnrS, ermB, blaOXA2-type) and intI1 gene as well as the amount of multi-resistance determinants were significantly lower in the discharges of photobioreactors where lake water was used to dilute wastewater.

        https://www.sciencedirect.com/science/article/abs/pii/S0043135418304585?via%3Dihub