摘要

       未经处理的废水可能含有高水平的抗生素抗性基因 (ARG)，这使得市政污水处理厂 (WWTP) 对控制 ARG 向环境中的释放至关重要。本研究的目的是调查两个三级污水处理厂中的各个处理步骤如何影响 ARG（拷贝/拷贝 16S rRNA 基因）的去除（拷贝数/mL）和相对丰度。九个 ARG 标记代表对常用抗生素的抗性，以及一个用于评估 ARG 迁移潜力的整合子基因 (intl1)，使用定量实时 PCR (qPCR) 进行量化。两个污水处理厂都符合省级污水排放法规，以去除含碳需氧量 (CBOD5) 和总悬浮固体。在所有样品中检测到十个 ARG 标记中的八个（intl1、sul1、sul2、tet(O)、ermB、blaCTX-M、blaTEM、qnrS）。相比之下，mecA 被断断续续地检测到，vanA 在所有样品中都保持在检测限以下。在使用曝气泻湖 (AL) 的植物中，总 ARG 标记丰度降低了 log 1.77 (p<0.05)，通过在植物中使用生物养分去除 (BNR) 系统进行处理，总 ARG 标记丰度降低了 2.69 log (p<0.05)。两个工厂中的 BNR 和二级澄清器步骤提供了最多的 ARG 去除。 ARGs 的相对丰度在 AL 植物中保持不变，在 BNR 植物中呈下降趋势。 CBOD5、硝酸盐和人类拟杆菌粪便标记物的水平与 ARG 浓度相关，表明这些变量可能有助于预测 ARG 去除。总之，来自污水处理厂的出水含有 8 个研究的 ARG 标记物，浓度范围从 0.01 到 3.6logcopies/mL，表明它们释放到环境中，然而，在这两个处理过程中，ARGs 的相对丰度并未富集。污水处理厂。

       Raw wastewater can contain high levels of antibiotic resistance genes (ARGs), making municipal wastewater treatment plants (WWTPs) critical for the control of the release of ARGs into the environment. The objective of this study was to investigate how individual treatment steps in two tertiary WWTPs affected the removal (copies/mL) and relative abundance of ARGs (copies/copies 16S rRNA genes). Nine ARG markers, representing resistance to commonly used antibiotics, as well as one integron gene (intl1) to assess ARG mobility potential, were quantified using quantitative real-time PCR (qPCR). Both WWTPs met provincial effluent regulations for removal of carbonaceous oxygen demand (CBOD5) and total suspended solids. Eight of the ten ARG markers (intl1, sul1, sul2, tet(O), ermB, blaCTX-M, blaTEM, qnrS) were detected in all samples. In contrast, mecA was detected intermittently and vanA remained below the detection limit in all samples. The total ARG marker abundances decreased by log 1.77 (p < 0.05) in the plant using an aerated lagoon (AL), and by 2.69 logs (p < 0.05) through treatment in the plant employing a biological nutrient removal (BNR) system. The BNR and secondary clarifier steps in both plants afforded the most removal of ARGs. The relative abundance of ARGs remained unchanged at the AL plant and showed a decreasing trend at the BNR plant. Levels of CBOD5, nitrate and the human Bacteroides fecal marker correlated with ARG concentrations, suggesting these variables may be useful in predicting ARG removal. In conclusion, the effluent coming from the WWTPs contained eight of the studied ARG markers in concentrations ranging from 0.01 to 3.6 log copies/mL, indicating their release into the environment, however, the relative abundance of ARGs was not enriched during treatment in the two WWTPs.

https://www.sciencedirect.com/science/article/abs/pii/S0048969718322885