摘要
      渗滤液是抗生素抗性基因（ARGs）的重要库，其正确处理与人类健康和生态系统安全密切相关。在这里，我们使用高通量qPCR来探索两个全尺寸渗滤液处理厂（LTP）中ARGs的去除行为，其中生物处理和膜过滤工艺是集成的。共检测到286个ARGs和55个可移动遗传元件（MGE），其中氨基糖苷类、多药类和MLSB抗性基因最为普遍和丰富。厌氧消化被发现是渗滤液的一个重要预处理过程，而膜生物反应器（MBR）中的缺氧/好氧罐由于其对ARGs的显著增殖作用而起到了ARGs培养箱的作用。集成膜过滤（UF-NF-RO）在去除ARGs方面表现出色，绝对丰度降低了3-6个数量级，从原始渗滤液中的约109拷贝/mL降低到流出物中的103-105拷贝/mL。我们的研究结果还表明，渗滤液处理过程显著改变了ARGs和细菌群落的组成。Procrustes分析和网络分析揭示了微生物和ARGs之间的强烈关联，并鉴定了几个中枢基因和细菌属。结构方程模型（SEMs）表明，细菌组成、MGE和基本水性质分别是形成原渗滤液、生物系统和过滤系统中ARGs动力学的关键驱动因素。值得注意的是，几种病原体（如克雷伯菌、弧菌、气单胞菌）与未经处理的渗滤液中的ARGs密切相关，并可能增加ARGs的传播风险。此外，生物系统中的插入序列将加速ARGs的水平基因转移。简言之，这项研究为工业规模LTP中ARGs的去除和传播行为的机制提供了新的见解。
Abstract
Leachate is a critical reservoir of antibiotic resistance genes (ARGs) and its proper treatment is closely related to human health and ecosystem safety. Here, we used high-throughput qPCR to explore the removal behavior of ARGs in two full-scale leachate treatment plants (LTPs) where biological treatment and membrane filtration processes were integrated. A total of 286 ARGs and 55 mobile genetic elements (MGEs) were detected, with aminoglycoside, multidrug and MLSB resistance genes being the most prevalent and abundant. Anaerobic digestion was found to be an important pretreatment process for leachate, while anoxic/aerobic tanks in membrane bioreactor (MBR) acted as incubators for ARGs due to their significant proliferation effect on ARGs. Integrated membrane filtration (UF-NF-RO) excelled in ARGs removal with absolute abundances reduced by 3 to 6 orders of magnitude, from about 109 copies/mL in raw leachate to 103-105 copies/mL in effluents. Our results also showed that leachate treatment processes significantly altered the composition of ARGs and bacterial communities. Procrustes analysis and network analysis revealed strong associations between microbes and ARGs, with several hub genes and bacterial genera identified. Structural equation models (SEMs) indicated that bacterial composition, MGEs and basic water properties were the key drivers shaping ARGs dynamics in the raw leachate, biological system and filtration system, respectively. Notably, several pathogens (e.g., Klebsiella, Vibrio, Aeromonas) were closely correlated with ARGs in raw leachate and may amplify the dissemination risks of ARGs. Moreover, insertion sequences in biological systems would accelerate the horizontal gene transfer of ARGs. In short, this study provides new insights into the mechanisms of ARGs removal and dissemination behavior in industrial-scale LTPs.

https://www.sciencedirect.com/science/article/abs/pii/S0043135422011848