摘要

抗生素耐药基因（ARGs）是一种新兴的污染物，在全球范围内对人类健康构成潜在威胁。城市污水处理厂（WWTPs）是产生抗药性细菌和释放到环境中的ARGs的主要来源。然而，在韩国，对ARGs的传播及其潜在机制以及在污水处理厂中可移动基因元件（MGEs）的动态研究还很少。本研究采用鸟枪宏基因组学，以2个活性污泥（AS）和2个厌氧消化污泥（ADS）为样本，对复杂的ARGs及其机制、细菌群落和4种形态的MGEs进行了分析。共检测到181个ARG亚型，隶属于22个ARG亚型，AS样品中的ARG丰度比ADS样品高1.3-2.0个数量级。多药耐药基因和杆菌肽耐药基因是AS样品中主要的ARG类型，其次是抗磺胺、四环素和β-内酰胺的ARG。然而，ADS样品中ARG类型的组成发生了显著变化。ADS样品中多重耐药基因和β-内酰胺耐药基因的丰度显著降低。ADS样品中MLS的抗性基因占优势，其次是对磺胺类药物和四环素类药物的抗性基因。此外，质粒是AS样品中的优势MGEs，而整合子（intI1）是ADS样品中的优势MGEs。这些结果提供了AS、ADS系统之间关于ARG类型和MGEs的流行率、差异模式的有价值的信息。

Antibiotic resistance genes (ARGs) are emerging contaminants that pose a potential threat to human health worldwide. Urban wastewater treatment plants (WWTPs) are a main source of both antibiotic-resistant bacteria and ARGs released into the environment. Nevertheless, the propagation of ARGs and their underlying mechanisms and the dynamics of mobile genetic elements (MGEs) in WWTPs have rarely been investigated in South Korea. In this study, shotgun metagenomic analysis was used to identify comprehensive ARGs and their mechanisms, bacterial communities, and MGEs from 4 configurations with 2 activated sludge (AS) and 2 anaerobic digestion sludge (ADS) samples. A total of 181 ARG subtypes belonging to 22 ARG types were broadly detected, and the ARG abundances in the AS samples were 1.3–2.0 orders of magnitude higher than in the ADS samples. Multidrug and bacitracin resistance genes were the predominant ARG types in AS samples, followed by ARGs against sulfonamide, tetracycline, and β-lactam. However, the composition of ARG types in ADS samples was significantly changed. The abundance of multidrug and β-lactam resistance genes was drastically reduced in the ADS samples. The resistance genes of MLS were the predominant, followed by ARGs against sulfonamide and tetracycline in the ADS samples. In addition, plasmids were the dominant MGEs in the AS samples, while integrons (intI1) were the dominant MGEs in the ADS samples. These results provide valuable information regarding the prevalence of ARG types and MGEs and the difference patterns between the AS and ADS systems.

https://link.springer.com/article/10.1007/s12275-020-9309-y