摘要
      抗生素耐药性的出现和传播是通过废水处理系统未经充分处理的废水产生的，这对接收环境和人类健康有害。采用宏基因组学和转录组学方法评估了南非德班三个污水处理厂（WWTP）中细菌病原体、抗生素抗性基因（ARGs）和移动遗传元件（MGE）的多样性和去除情况。在样本中总共发现了23个病原菌属，包括肠道和新出现的机会性病原体。气单胞菌和不动杆菌是在进水宏基因组中检测到的最主要的病原体，而进水转录物显示大肠杆菌和不动细菌是最主要的病原。Shannon Wiener指数显示，在两个选定的处理厂中，细菌多样性从影响物到最终废水都有所增加。ARG类型，包括对氨基糖苷类、β-内酰胺酶、四环素和磺酰胺类产生耐药性的ARG类型在进水和出水样品中都很丰富。结果进一步表明，MGE-ARGs关联是ARG持续进入最终废水的主要驱动因素。这包括5个质粒：R338-R151（sulI）、pRH-1238（strB）、pPM91（aadA）、pRH-1238（aadA4-5）、pRH-1238（sulII）；两个1类整合子（aadA和arr）和1个转座子Tn4351（tetX）。在转录物中，MGE-ARG结合显示两个质粒：pRH-1238（aadA）和pPM91（aadA），以及一个杂交质粒R338-R151（sulI）。很明显，在所有污水处理厂中，氯化对MGE-ARG的结合几乎没有影响。综合来看，这项研究强调了经处理的废水中存在的细菌病原体、ARGs和MGE，这可以促进抗生素耐药性的传播和下游环境中潜在的基因共享。
Abstract
The emergence and spread of antibiotic resistance through insufficiently treated effluents from wastewater treatment systems are detrimental to the receiving environment and human health. Metagenomic and transcriptomic approaches were employed to assess the diversity and the removal of bacterial pathogens, antibiotic-resistant genes (ARGs) and mobile genetic elements (MGEs) in three wastewater treatment plants (WWTPs) in Durban, South Africa. In total, 23 pathogenic bacterial genera, including enteric and emerging opportunistic pathogens, were found abundant in the samples. Aeromonas and Acinetobacter spp were the most dominant pathogens detected in the influent metagenomes, while the influent transcripts showed Escherichia and Acinetobacter spp as the most dominant pathogens. Shannon-Wiener indices showed that the bacterial diversity increased from influents to final effluents in two selected treatment plants. ARG types, including those conferring resistance to aminoglycosides, beta-lactamases, tetracycline and sulfonamide were abundant in both influent and effluent samples. Results further exposed that MGE-ARGs associations were the main drivers of ARG persistence into final effluents. This included 5 plasmids: R338-R151 (sulI), pRH-1238 (strB), pPM91 (aadA), pRH-1238 (aadA4–5), pRH-1238 (sulII); two class 1 integrons (aadA and arr) and 1 transposon Tn4351(tetX). In transcripts, MGE-ARG association showed two plasmids: pRH-1238 (aadA) and pPM91(aadA) and one hybrid plasmid R338-R151 (sulI). It was apparent across all the WWTPs that chlorination had little or no effect on MGE-ARG association . Combined, this study has highlighted the presence of bacterial pathogens, ARGs and MGEs in treated effluents, which can encourage the propagation of antibiotic resistance and potential sharing of genes in the downstream environments.

https://www.sciencedirect.com/science/article/abs/pii/S2213343722004699