摘要

       城市污水处理厂 (UWTP) 是抗生素耐药性的蓄水池。废水处理改变了细菌群落，不可避免地影响抗生素抗性细菌和抗生素抗性基因 (ARG) 的命运。一些细菌群是 ARG 的主要载体，因此，在废水处理过程中消除它们可能有助于提高抗性去除效率。这项研究是在全面的 UWTP 上进行的，评估了细菌群落和 ARGs 负载的变化，并探讨了它们之间可能的关联。为此，我们对未经处理的废水 (RWW)、二级出水 (sTWW)、紫外线消毒 (tTWW) 和消毒后的样品中的细菌群落组成（16S rRNA 基因 Illumina 测序）和 ARGs 丰度（实时 PCR）进行了表征。储存 3 天以监测可能的细菌再生 (tTWW-RE)。还列举了可培养的肠杆菌。
       二级处理与最显着的细菌群落变化相关，并且与 ARGs 丰度的约 2 log-unit 减少相吻合。相比之下，在 sTWW 紫外线消毒后，没有观察到细菌群落组成和 ARGs 丰度的显着变化。然而，在紫外线处理后，可培养肠杆菌的活力损失显示出约 2 个对数单位的减少。分析的 ARG（qnrS、blaCTX-M、blaOXA-A、blaTEM、blaSHV、sul1、sul2 和 intI1）与 RWW 中比其他类型水更丰富的分类群密切相关，并且与人类和动物相关，例如弯曲杆菌科、毛单胞菌科、气单胞菌科、莫拉菌科和拟杆菌科的成员。
       进一步了解废水处理过程中细菌群落的动态及其与 ARG 变化的关系可能有助于提供对废水处理优化有用的信息，旨在更有效地控制阻力。

Urban wastewater treatment plants (UWTPs) are reservoirs of antibiotic resistance. Wastewater treatment changes the bacterial community and inevitably impacts the fate of antibiotic resistant bacteria and antibiotic resistance genes (ARGs). Some bacterial groups are major carriers of ARGs and hence, their elimination during wastewater treatment may contribute to increasing resistance removal efficiency. This study, conducted at a full-scale UWTP, evaluated variations in the bacterial community and ARGs loads and explored possible associations among them. With that aim, the bacterial community composition (16S rRNA gene Illumina sequencing) and ARGs abundance (real-time PCR) were characterized in samples of raw wastewater (RWW), secondary effluent (sTWW), after UV disinfection (tTWW), and after a period of 3 days storage to monitoring possible bacterial regrowth (tTWW-RE). Culturable enterobacteria were also enumerated.
       Secondary treatment was associated with the most dramatic bacterial community variations and coincided with reductions of ~2 log-units in the ARGs abundance. In contrast, no significant changes in the bacterial community composition and ARGs abundance were observed after UV disinfection of sTWW. Nevertheless, after UV treatment, viability losses were indicated ~2 log-units reductions of culturable enterobacteria. The analysed ARGs (qnrS, blaCTX-M, blaOXA-A, blaTEM, blaSHV, sul1, sul2, and intI1) were strongly correlated with taxa more abundant in RWW than in the other types of water, and which associated with humans and animals, such as members of the families Campylobacteraceae, Comamonadaceae, Aeromonadaceae, Moraxellaceae, and Bacteroidaceae.
       Further knowledge of the dynamics of the bacterial community during wastewater treatment and its relationship with ARGs variations may contribute with information useful for wastewater treatment optimization, aiming at a more effective resistance control.
https://www.sciencedirect.com/science/article/pii/S0160412018303817