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.

中文翻译：

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通过宏基因组分析，探索城市污水处理厂中活性污泥和厌氧消化污泥中的抗生素抗药性。

抗生素抗性基因（ARG）是新兴污染物，对全球人类健康构成潜在威胁。城市污水处理厂（WWTP）是释放到环境中的抗生素抗性细菌和ARG的主要来源。然而，在韩国，很少有人研究过污水处理厂中ARGs的传播及其潜在机制和移动遗传元件（MGE）的动力学。在这项研究中，shot弹枪宏基因组分析被用于从2种活性污泥（AS）和2种厌氧消化污泥（ADS）样品的4种配置中识别全面的ARG及其机制，细菌群落和MGE。广泛检测到属于22种ARG类型的181种ARG亚型，并且AS样品中的ARG丰度比ADS样品高1.3-2.0个数量级。在AS样品中，多药耐药和杆菌肽耐药基因是主要的ARG类型，其次是针对磺酰胺，四环素和β-内酰胺的ARG。但是，ADS样品中ARG类型的组成发生了显着变化。在ADS样品中，多种药物和β-内酰胺抗性基因的丰度大大降低。在ADS样品中，以MLS的抗性基因为主，其次为抗磺酰胺和四环素的ARG。此外，质粒是AS样品中的主要MGE，而整合素（在ADS样品中，多种药物和β-内酰胺抗性基因的丰度大大降低。在ADS样品中，以MLS的抗性基因为主，其次为抗磺酰胺和四环素的ARG。此外，质粒是AS样品中的主要MGE，而整合素（在ADS样品中，多种药物和β-内酰胺抗性基因的丰度大大降低。在ADS样品中，以MLS的抗性基因为主，其次为抗磺酰胺和四环素的ARG。此外，质粒是AS样品中的主要MGE，而整合素（intI1）是ADS样品中的主要MGE。这些结果为有关ARG类型和MGE的流行以及AS和ADS系统之间的差异模式提供了有价值的信息。