Department of Environmental Microbiology, Faculty of Environmental Sciences, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1 Str., 10-720 Olsztyn, Poland.
Sci Total Environ. 2018 Oct 15;639:304-315. doi: 10.1016/j.scitotenv.2018.05.165. Epub 2018 May 20.
Biological treatment processes at wastewater treatment plants (WWTPs), which are the most common methods of sewage treatment, could cause selective elimination and/or changes in the proportions of phenotypes/genotypes within bacterial populations in effluent. Therefore, WWTPs based on activated sludge used in sewage treatment constitute an important reservoir of enteric bacteria which harbour potentially transferable resistance genes. Together with treated wastewater, these microorganisms can penetrate the soil, surface water, rural groundwater supplies and drinking water. Because of this, the aim of this study was to determine the impact of various modification of sewage treatment (the conventional anaerobic/anoxic/oxic (A2/O) process, mechanical-biological (MB) system, sequencing batch reactors (SBR), mechanical-biological system with elevated removal of nutrients (MB-ERN)) on the amount of antibiotic resistant bacteria (ARB) (including E. coli) and antibiotic resistance genes (ARGs) in sewage flowing out of the 13 treatment plants using activated sludge technology. There were no significant differences in ARB and ARGs regardless of time of sampling and type of treated wastewater (p > 0.05). The highest percentage of reduction (up to 99.9%) in the amount of ARB and ARGs was observed in WWTPs with MB and MB-ERN systems. The lowest reduction was detected in WWTPs with SBR. A significant increase (p < 0.05) in the percentage of bacteria resistant to the new generation antibiotics (CTX and DOX) in total counts of microorganisms was observed in effluents (EFF) from WWTPs with A2/O system and with SBR. Among all ARGs analyzed, the highest prevalence of ARGs copies in EFF samples was observed for sul1, tet(A) and qepA, the lowest for bla and bla. Although, the results of presented study demonstrate high efficiency of ARB and ARGs removal during the wastewater treatment processes, especially by WWTPs with MB and MB-ERN systems, EFF is still an important reservoir of ARGs which can be transferred to other microorganisms.
污水处理厂（WWTP）中的生物处理工艺是最常见的污水处理方法，可能会导致出水中细菌种群的表型/基因型选择性消除和/或变化。因此，基于活性污泥的 WWTP 是肠细菌的重要储存库，其中含有潜在可转移的耐药基因。这些微生物与经过处理的废水一起，可渗透土壤、地表水、农村地下水供应和饮用水。因此，本研究的目的是确定各种污水处理工艺（传统的厌氧/缺氧/好氧（A2/O）工艺、机械-生物（MB）系统、序批式反应器（SBR）、具有提高营养去除率的机械-生物系统（MB-ERN））对 13 个采用活性污泥技术的污水处理厂流出污水中抗生素耐药细菌（ARB）（包括大肠杆菌）和抗生素耐药基因（ARGs）数量的影响。无论采样时间和处理后废水的类型如何，ARB 和 ARGs 没有显著差异（p＞0.05）。在具有 MB 和 MB-ERN 系统的 WWTP 中，观察到 ARB 和 ARGs 数量的最高减少率（高达 99.9%）。在具有 SBR 的 WWTP 中，检测到的减少率最低。在具有 A2/O 系统和 SBR 的 WWTP 的流出物（EFF）中，观察到总微生物计数中对新一代抗生素（CTX 和 DOX）具有抗性的细菌百分比显著增加（p＜0.05）。在所分析的所有 ARGs 中，在 EFF 样品中观察到 sul1、tet(A)和 qepA 的 ARGs 拷贝数最高，bla 和 bla 的 ARGs 拷贝数最低。尽管本研究结果表明，在污水处理过程中，ARB 和 ARGs 的去除效率很高，特别是在具有 MB 和 MB-ERN 系统的 WWTP 中，但 EFF 仍然是 ARGs 的重要储存库，这些 ARGs 可转移到其他微生物中。
