摘要

       再生水为解决生活密度高、自然水资源有限的城市缺水问题提供了一种替代供水方式。本研究以常规与膜生物反应器（MBR）处理的污水处理厂（WWTP）为研究对象，对污水处理厂（wtp）6个阶段的废水基因组进行了抗生素抗性基因（ARGs）和细菌多样性及1类整合子整合酶（intl1）相对丰度的评价。对12类抗生素（精氨酸类型）具有耐药性的精氨酸在整个治疗阶段持续存在，其中包括对氨基糖苷类药物（aadA、aph（6）-I、aph（3’）-I、A A C（6’）-I、aac（6’）-II、ant（2’）-I）、β-内酰胺类药物（A类、C类、D类β-内酰胺酶（bla-OXA））具有耐药性的基因、氯霉素（乙酰转移酶、出口商，floR，cmIA），福霉素（rosAB），大环内酯林可酰胺链霉素（macAB，ereA，ermFB），多药耐药（转运子亚单位），多粘菌素（arnA），喹诺酮类（qnrS），利福霉素（arr），磺胺类（sul1，sul2）和四环素（tetM，tetG，tetE，tet36，tet39，tetR，tet43，tetQ，tetX）。尽管污泥和MBR废水中的ARG亚型相对于进水减少了多样性，但检测到了临床相关的β-内酰胺酶（即bla-KPC、bla-OXA），为废水处理过程中ARG传播的其他潜在点源提供了线索。为了更深入地了解MBR去除过程中可能存活的细菌类型，从MBR废水的亚基因组数据中回收了基因组箱。共收集到101个接近完整的基因组，并对其进行了注释，揭示了MBR出水中含有多种金属抗性基因和arg的细菌。特别是三个垃圾箱分别隶属于smegmatis分枝杆菌、Iwofii不动杆菌和嗜冷黄杆菌，并分别携带已获得的ARGs aac（2’）-Ib、bla OXA-278和tet36。在指示菌方面，与MBR出水（5.3-7.4）相比，大肠杆菌、肠球菌和铜绿假单胞菌从进水到常规处理出水的累积对数去除值（LRV）较低（0-2.4）。我们的结论是，MBR是一种有效的减少粪便指标和ARGs的处理方法；然而，MBR处理的废水（<8mpn/100ml）中铜绿假单胞菌的不完全去除以及ARGs和intl1的存在强调了在再利用之前是否需要进一步处理的必要性。

       Reclaimed water provides a water supply alternative to address problems of scarcity in urbanized cities with high living densities and limited natural water resources. In this study, wastewater metagenomes from 6 stages of a wastewater treatment plant (WWTP) integrating conventional and membrane bioreactor (MBR) treatment were evaluated for diversity of antibiotic resistance genes (ARGs) and bacteria, and relative abundance of class 1 integron integrases (intl1). ARGs confering resistance to 12 classes of antibiotics (ARG types) persisted through the treatment stages, which included genes that confer resistance to aminoglycoside [aadA, aph(6)-I, aph(3')-I, aac(6')-I, aac(6')-II, ant(2″)-I], beta-lactams [class A, class C, class D beta-lactamases (bla _OXA)], chloramphenicol (acetyltransferase, exporters, floR, cmIA), fosmidomycin (rosAB), macrolide-lincosamide-streptogramin (macAB, ereA, ermFB), multidrug resistance (subunits of transporters), polymyxin (arnA), quinolone (qnrS), rifamycin (arr), sulfonamide (sul1, sul2), and tetracycline (tetM, tetG, tetE, tet36, tet39, tetR, tet43, tetQ, tetX). Although the ARG subtypes in sludge and MBR effluents reduced in diversity relative to the influent, clinically relevant beta lactamases (i.e., bla _KPC, bla _OXA) were detected, casting light on other potential point sources of ARG dissemination within the wastewater treatment process. To gain a deeper insight into the types of bacteria that may survive the MBR removal process, genome bins were recovered from metagenomic data of MBR effluents. A total of 101 close to complete draft genomes were assembled and annotated to reveal a variety of bacteria bearing metal resistance genes and ARGs in the MBR effluent. Three bins in particular were affiliated to Mycobacterium smegmatis, Acinetobacter Iwoffii, and Flavobacterium psychrophila, and carried aquired ARGs aac(2')-Ib, bla _OXA-278, and tet36 respectively. In terms of indicator organisms, cumulative log removal values (LRV) of Escherichia coli, Enterococci, and P. aeruginosa from influent to conventional treated effluent was lower (0-2.4), compared to MBR effluent (5.3-7.4). We conclude that MBR is an effective treatment method for reducing fecal indicators and ARGs; however, incomplete removal of P. aeruginosa in MBR treated effluents (<8 MPN/100 mL) and the presence of ARGs and intl1 underscores the need to establish if further treatment should be applied prior to reuse.

       https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6387931/