摘要
      畜禽养殖场处理后的废水是抗生素抗性基因（ARGs）的重要库，也是环境中ARGs的主要来源。然而，关于ARGs在不同类型畜牧场处理废水中的分布和驱动因素的报道很少。本研究收集了69个不同类型的大型畜牧场（包括肉鸡、蛋鸡和养猪场）的处理废水，并分析了11种ARGs亚型、2种可移动遗传元件（MGE）和细菌群落结构。结果显示，NDM-1和mcr-1的检测率分别为90%和43%，其他ARG的检测率为100%。肉鸡养殖场中ARGs（如tetA、tetX和strB）的相对丰度显著高于蛋鸡养殖场，但细菌α多样性显著低于其他养殖场。此外，尽管处理过程对处理废水的理化性质的影响比牲畜类型更大，但牲畜类型是影响处理废水中细菌群落的主要因素。对ARGs潜在宿主菌的分析显示，不同类型畜牧场处理废水中ARGs的宿主菌存在显著差异。肉鸡养殖场ARGs的宿主菌主要属于放线菌，蛋鸡养殖场主要属于变形菌，养猪场主要属于厚壁菌门。此外，冗余分析表明，ARGs的分布可能是多种驱动因素在不同类型的畜牧场中共同作用的结果，其中tnpA和NH4+-N是主要影响因素。本研究揭示了不同类型畜牧场处理废水中典型ARG分布的多种驱动因素，为农业环境中ARG污染的防治提供了基础数据。
Abstract
Treated wastewater from livestock farms is an important reservoir for antibiotic resistance genes (ARGs), and is a main source of ARGs in the environment. However, the distribution and driving factors of ARGs in treated wastewater from different types of livestock farms are rarely reported. In this study, treated wastewater from 69 large-scale livestock farms of different types, including broiler, layer, and pig farms, was collected, and 11 subtypes of ARGs, 2 mobile genetic elements (MGEs) and bacterial community structure were analyzed. The results revealed detection rates of NDM-1 and mcr-1 of 90 % and 43 %, respectively, and the detection rates of other ARGs were 100 %. The relative abundance of ARGs, such as tetA, tetX and strB, in broiler farms was significantly higher than that in layer farms, but the bacterial α diversity was significantly lower than that in other farm types. Furthermore, although the treatment process had a greater impact on the physicochemical properties of the treated wastewater than the livestock type, livestock type was the main factor affecting the bacterial community in the treated wastewater. The analysis of potential host bacteria of ARGs revealed significant differences in the host bacteria of ARGs in treated wastewater from different types of livestock farms. The host bacteria of ARGs in broiler farms mainly belonged to Actinobacteria, layer farms mainly belonged to Proteobacteria, and pig farms mainly belonged to Firmicutes. Additionally, redundancy analysis showed that the distribution of ARGs may have resulted from the combination of multiple driving factors in different types of livestock farms, among which tnpA and NH4+-N were the main influencing factors. This study revealed multiple driving factors for the distribution of typical ARGs in treated wastewater from different types of livestock farms, providing basic data for the prevention and control of ARG pollution in agricultural environments.

https://www.sciencedirect.com/science/article/abs/pii/S0048969722049361