摘要

       在具有一系列开放水域的自由水面人工湿地 (FWS CW) 中，对大肠杆菌和产超广谱 β-内酰胺酶大肠杆菌 (ESBL E.coli) 的命运进行了为期一年的研究。植物池（香蒲或芦苇），接收来自废水处理厂的污水。在整个研究期间，从 FWS CW 的所有采样区域都检测到并分离了 ESBL 大肠杆菌。无论样品的来源如何，它们都代表了大肠杆菌总数的 1‰。两个主要因素影响了大肠杆菌和 ESBL 大肠杆菌的对数去除：季节和植被的存在。在 FWS CW 的入口和出口之间，大肠杆菌的日志去除范围从温暖季节（夏季和秋季）的 1.5 到寒冷季节（冬季和春季）的 3.0。植被区的大肠杆菌浓度在寒冷季节显着降低，但在温暖季节增加，表明植物生长阶段对大肠杆菌存活率的影响。在我们研究期间收集的 369 个 ESBL 大肠杆菌分离株中，84% 携带 CTX-M-ESBL 类型，55.3% 在质粒 DNA 上携带 bla 基因。此外，93% 的 ESBL 大肠杆菌分离株具有多重耐药性，但耐药菌株的比例沿 FWS CW 没有显着变化。 ESBL 大肠杆菌使用基于 Achtman 方案的 7 个基因通过 MLST 分析表征。从 FWS CW 和接收河流中收集的肌细胞的水、沉积物、根和粪便中分离出的 ESBL 大肠杆菌具有基因型相关性，表明产 ESBL 的大肠杆菌在整个 FWS CW 和接收河流中持续存在和循环。总体而言，这些观察表明 FWS CW 可以有效处理 ESBL 大肠杆菌废水消毒，并可以限制其在水生环境中的传播。

       The fates of Escherichia coli and extended-spectrum beta-lactamase-producing E. coli (ESBL E. coli) were studied over a period of one year in a free water surface constructed wetland (FWS CW) with a succession of open water zones and vegetation ponds (Typha or Phragmites), that received the effluent from a wastewater treatment plant. ESBL E. coli were detected and isolated from all sampling areas of the FWS CW throughout the study period. They represented 1‰ of the total E. coli population regardless of the origin of samples. Two main factors affected the log removal of E. coli and of ESBL E. coli: the season and the presence of vegetation. Between the inlet and the outlet of the FWS CW, the log removal of E. coli ranged from 1.5 in the warmer season (summer and fall) to 3.0 in the colder season (winter and spring). The concentrations of E. coli decreased significantly in the vegetated areas during the colder season, but increased in the warmer season, suggesting an effect of the plant growth stage on the survival of E. coli. Among the 369 ESBL E. coli isolates collected during our study, 84% harbored the CTX-M-ESBL type and 55.3% carried bla genes on plasmid DNA. Furthermore, 93% of the ESBL E. coli isolates were multidrug resistant but the proportion of resistant strains did not change significantly along the FWS CW. ESBL E. coli were characterized by MLST analysis using the 7 genes based Achtman Scheme. ESBL E. coli isolated from water, sediments, roots and feces of myocastors collected in the FWS CW and in the recipient river were genotypically related, suggesting persistence and circulation of the ESBL producing E. coli throughout the FWS CW and in the receiving river. Overall, these observations show that FWS CW could be an efficient treatment for ESBL E. coli disinfection of wastewater and could limit their dissemination in the aquatic environment.

https://www.sciencedirect.com/science/article/abs/pii/S0043135416306157