摘要
      随着畜禽养殖业的迅速发展，抗生素和重金属正作为饲料添加剂进入土壤环境。然而，它们与抗生素抗性基因（ARGs）、微生物和环境因素的关系尚不清楚。本研究选择镉（Cd）和磺胺嘧啶（SD）分别作为代表性重金属和抗生素物质，研究环境因素、微生物、可移动遗传元素（MGEs）和ARGs之间的关系。单独或组合添加Cd和SD，增加了总ARGs和MGE的丰度。总ARGs的丰度在C2和C8（仅添加Cd的组）分别增加了0.89倍和1.06倍，在S10和S100（仅添加SD的组）增加了1.61倍和6.53倍，在C2S10、C2S100、C8S10和C8S100（组合有Cd和SD的组中）分别增加7.29倍、7.62倍、2.32倍和6.80倍。变形杆菌门和拟杆菌门是最丰富的细菌门。MGE（尤其是intI1）对ARGs的影响最大，并在其繁殖和表达中发挥着至关重要的作用。探索土壤中重金属和抗生素对ARGs的影响，对于全面评估其对ARG的生态和环境风险具有重要意义。
Abstract
With rapid developments in livestock and poultry farming, antibiotics and heavy metals are entering the soil environment as feed additives. However, their relationships with antibiotic resistance genes (ARGs), microorganisms, and environmental factors are unclear. In this study, cadmium (Cd) and sulfadiazine (SD) were selected as representative heavy metal and antibiotic substances, respectively, to investigate the relationships among environmental factors, microorganisms, mobile genetic elements (MGEs), and ARGs. Addition of Cd and SD, both individually and in combination, increased the abundances of total ARGs and MGEs. The abundance of total ARGs increased by 0.89-fold and 1.06-fold in C2 and C8 (only-Cd-added groups), 1.61-fold and 6.53-fold in S10 and S100 (only-SD-added groups), and 7.29-fold, 7.62-fold, 2.32-fold, and 6.80-fold in C2S10, C2S100, C8S10, and C8S100 (groups with Cd and SD in combinations), respectively. Proteobacteria and Bacteroidetes were the most abundant bacterial phyla. MGEs (especially intI1) had the greatest impact on ARGs and played a crucial role in their propagation and expression. Exploring the effects of heavy metals and antibiotics in soil on ARGs is important for comprehensively assessing their ecological and environmental risks to ARGs.

https://www.sciencedirect.com/science/article/pii/S0957582022009727