College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin, China.
School of Environmental Science and Engineering, Tianjin University, Tianjin, China.
Sci Total Environ. 2017 Mar 1;581-582:136-143. doi: 10.1016/j.scitotenv.2016.12.063. Epub 2017 Jan 5.
At present, very little is known about the persistence and spread pathway of KPC-2 genes in the environment. Our previous study reported the prevalence and persistence of KPC-2 genes in wastewater treatment plants (WWTPs). In the present work, we investigated the occurrence and fate of KPC-2 genes in a WWTP discharge-receiving river and studied the effect of WWTP discharges on the prevalence of KPC-2 genes and host bacteria in the receiving river. It is observed that a considerable level of KPC-2 genes occurred in the receiving river, and a significant increase of bla abundance in the downstream following WWTP discharge was observed compared to the upstream. Furthermore, opportunistic pathogens with 100% identical bla sequence, like Escherichia coli and Kluyvera georgiana, were isolated from both WWTP and its receiving water, whereas no bla carrying bacteria was detected in the upstream. These findings indicated that the treated wastewater discharges have a considerable influence on bla levels in the receiving river. Interestingly, there is no correlation between concentrations of antibiotics and bla concentrations, demonstrating that the increase of KPC-2 genes in the receiving river is mainly due to WWTP release. This finding is important because it illustrates a significant pathway for KPC-2 gene proliferation to the environment.
目前，人们对环境中 KPC-2 基因的持久性和传播途径知之甚少。我们之前的研究报告了污水处理厂（WWTP）中 KPC-2 基因的流行和持久性。在本工作中，我们调查了 KPC-2 基因在 WWTP 排放接收河流中的发生和命运，并研究了 WWTP 排放对接收河流中 KPC-2 基因和宿主细菌流行的影响。结果表明，在接收河流中存在相当水平的 KPC-2 基因，并且与上游相比，在 WWTP 排放后下游的 bla 丰度显著增加。此外，从 WWTP 和其接收水中分离到了具有 100%相同 bla 序列的机会性病原体，如大肠杆菌和克吕沃尔氏菌，而在上游未检测到携带 bla 的细菌。这些发现表明，处理后的废水排放对接收河流中的 bla 水平有相当大的影响。有趣的是，抗生素浓度与 bla 浓度之间没有相关性，这表明接收河流中 KPC-2 基因的增加主要归因于 WWTP 的排放。这一发现很重要，因为它说明了 KPC-2 基因向环境中增殖的一个重要途径。
