摘要
      水生环境中的抗生素耐药性基因（ARGs）因其对公众健康的风险而在全球范围内受到重视。生物电化学增强人工湿地在减少ARGs丰度方面具有巨大潜力。然而，ARGs及其在不同生物电化学[微生物燃料电池（MFC）和微直流电（EC）]增强人工湿地（CW）中的流动性尚不清楚。在本研究中，在连续输入磺胺甲恶唑（SMX）的情况下，通过定量PCR和宏基因组学方法测定了污水和基质中磺酰胺抗性基因（sul-ARGs）的出现及其在MFC CWs和EC-CW中的潜在移动性和宿主。结果表明，生物电化学技术降低了出水和下层基质中sul-ARGs的相对丰度（RA），这是由于SMX去除率高，并且细菌在没有ARGs的情况下膨胀。然而，EC-CW中sul-ARGs的RA高于MFC-CW。基于宏基因组分析，SMX促进了EC-CW和MFC-CW中非对应类型的ARGs和对应类型的sul-ARGs的共同选择，并且由质粒介导的ARG比染色体中编码的ARG更普遍。杆菌肽ARGs和sul-ARGs是优势型，并且EC-CW和MFC-CW中ARGs的优势亚型相似，只有sul1表现出显著差异（p<0.01）。sul-ARGs的优势宿主的丰度以及ARGs和可移动遗传元件的分布可能导致EC-CW和MFC-CW中sul-ARG的差异。
Abstract
Antibiotic resistance genes (ARGs) in aquatic environments have been highlighted on a global scale because of their risks to public health. Bioelectrochemistry-enhanced constructed wetlands have great potential for reducing the abundance of ARGs. However, the profiles of ARGs and their mobility in different bioelectrochemistry [microbial fuel cell (MFC) and micro direct current (EC)]-enhanced constructed wetlands (CW) are unclear. In this study, the occurrence of sulfonamide resistance genes (sul ARGs) in effluent and substrate and their potential mobility and hosts in MFC-CWs and EC-CW were determined by quantitative PCR and metagenomics approach under the continuous input of sulfamethoxazole (SMX). The results showed that the relative abundance (RA) of sul ARGs in the effluent and the lower substrate layer were decreased by bioelectrochemical technology owing to high SMX removal and the expansion of bacteria without ARGs. However, the RA of sul ARGs in the EC-CW was higher than that in the MFC-CW. Based on metagenomic analysis, SMX promoted the co-selection of the non-corresponding types of ARGs and corresponding types of sul ARGs in the EC-CW and MFC-CW, and ARGs mediated by plasmids were more prevalent than those encoded in chromosomes. Bacitracin ARGs and sul ARGs were the dominant types, and the dominant subtypes of ARGs in the EC-CW and MFC-CW were similar, with only sul1 showing significant difference (p < 0.01). An obvious difference in the proliferation and mobility of ARGs between the EC-CW and MFC-CW was observed. The abundance of dominant hosts for sul ARGs and the distribution of ARGs and mobile genetic elements might result in differences in sul ARGs in the EC-CW and MFC-CW.

https://www.sciencedirect.com/science/article/abs/pii/S138589472203491X