摘要
      废水处理厂（WWTP）被认为是抗生素耐药性细菌（ARBs）和抗生素耐药性基因（ARGs）的重要来源，可能在环境中消除和传播抗生素耐药性（AMR）方面发挥作用。需要有关城市污水处理厂中常用的不同处理技术去除AMR的详细信息。本研究采用不同的技术：WWTP-A（常规活性污泥-CAS）、WWTP-B（UASB反应器后接生物滴滤器）和WWTP-C（改性活性污泥后接紫外线消毒-MAS/UV），调查了污水处理厂中ARB的发生、去除和表征。收集了未经处理的污水（RI）和处理过的污水（TE）的样本，并通过使用11种抗生素的基于培养的方法，在一年内对抗生素耐药性进行了表征。与CAS（1对数单位）和UASB/BTF（0.5对数单位）相比，MAS有效地减少了ARB计数（2至3对数单位）。RI和TE样品中可培养ARB的组成不同。RI以大肠杆菌为主（56/118）；而在TE大肠杆菌（31/118）中紧随其后的是芽孢杆菌（22/118）、志贺菌（14/118）和肠球菌（14/118。大多数已鉴定的分离株（370/394）含有至少两个ARG，在80%以上的分离株中检测到4个或更多的ARG（int1、blaTEM、TetA、sul1和qnrB）。在CAS和MAS处理后的流出物中观察到耐药率降低；而在来自UASB/BTF的经处理的流出物中和UV消毒阶段之后观察到轻微增加。来自RI（27/32）和TE（21/33）样品的84.3%的分离株具有多药耐药性（MDR）表型，52.3%的分离物（34/65）对碳青霉烯类（亚胺培南、美罗培南、厄他培南）具有耐药性。结果表明，经处理的废水仍然是耐多药细菌和ARGs传播到水生环境的来源。观察到的ARB数量的显著减少加强了生物污水处理的重要性。然而，需要实施额外的治疗来缓解MDR细菌释放到环境中。
Abstract
Wastewater treatment plants (WWTPs) are recognized as important sources of Antibiotic Resistant Bacteria (ARBs) and Antibiotic Resistant Genes (ARGs), and might play a role in the removal and dissemination of antimicrobial resistance (AMR) in the environment. Detailed information about AMR removal by the different treatment technologies commonly applied in urban WWTPs is needed. This study investigated the occurrence, removal and characterization of ARBs in WWTPs employing different technologies: WWTP-A (conventional activated sludge-CAS), WWTP-B (UASB reactor followed by biological trickling filter) and WWTP-C (modified activated sludge followed by UV disinfection-MAS/UV). Samples of raw sewage (RI) and treated effluent (TE) were collected and, through the cultivation-based method using 11 antibiotics, the antibiotic resistance profiles were characterized in a one-year period. MAS was effective in reducing ARB counts (2 to 3 log units), compared to CAS (1 log unit) and UASB/BTF (0.5 log unit). The composition of cultivable ARB differed between RI and TE samples. Escherichia was predominant in RI (56/118); whilst in TE Escherichia (31/118) was followed by Bacillus (22/118), Shigella (14/118) and Enterococcus (14/118). Most of the isolates identified (370/394) harboured at least two ARGs and in over 80 % of the isolates, 4 or more ARG (int1, blaTEM, TetA, sul1 and qnrB) were detected. A reduction in the resistance prevalence was observed in effluents after CAS and MAS processes; whilst a slight increase was observed in treated effluents from UASB/BTF and after UV disinfection stage. The multi-drug resistance (MDR) phenotype was attributed to 84.3 % of the isolates from RI (27/32) and 63.6 % from TE (21/33) samples and 52.3 % of the isolates (34/65) were resistant to carbapenems (imipenem, meropenem, ertapenem). The results indicate that treated effluents are still a source for MDR bacteria and ARGs dissemination to aquatic environments. The importance of biological sewage treatment was reinforced by the significant reductions in ARB counts observed. However, implementation of additional treatments is needed to mitigate MDR bacteria release into the environment.

https://www.sciencedirect.com/science/article/abs/pii/S0048969722064750