Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
School of Fisheries and Life Science, Dalian Ocean University, Dalian 116023, China.
Environ Pollut. 2020 Jun;261:114155. doi: 10.1016/j.envpol.2020.114155. Epub 2020 Feb 10.
The increasing prevalence and spread of antibiotic resistance genes (ARGs) in intensive aquaculture environments are of great concern to food safety and public health. However, the level of ARGs and their potential propagation factors in an industrial recirculating aquaculture system (RAS) have not previously been comprehensive explored. In this study, the levels of 14 different ARG markers and 2 kinds of mobile genetic elements (MGEs) were investigated in a RAS (including water, fish, feces, pellet feed meal, and biofilm samples) located northern China. qnrA, qnrB, qnrS, qepA, aac(6')-Ib, and floR were dominant ARGs, which average concentration levels were presented at 4.51-7.74 copies/L and 5.36-13.07 copies/g, respectively, suggesting that ARGs were prevalent in RAS with no recorded history of antibiotic use. Elevated level of ARGs was found in water of RAS even after the final UV treatment compared with its influent. In RAS, Proteobacteria, Verrucomicrobia, Bacteroidetes, and Planctomycetes were the predominant phyla. Notably, elevated levels of potential opportunistic pathogens were observed along with abundant ARGs suggesting an increasing risk of capturing ARGs and MGEs for human pathogens. This study has revealed for the first time that reared fish, their feces, pellet feed meal as the introduction sources and the selection roles of treatment units co-driven the ARG profile, and the co-selection of water environmental factors and their consequently induced bacterial community shifts formed by their influence are the determining drivers for the ARG propagation in RAS.
抗生素耐药基因（ARGs）在集约化水产养殖环境中的日益流行和传播，对食品安全和公共健康构成了极大的关注。然而，工业循环水产养殖系统（RAS）中 ARGs 的水平及其潜在的传播因素尚未得到全面的研究。在本研究中，对位于中国北方的 RAS（包括水、鱼、粪便、颗粒饲料和生物膜样本）中的 14 种不同的 ARG 标记物和 2 种移动遗传元件（MGEs）的水平进行了调查。qnrA、qnrB、qnrS、qepA、aac(6')-Ib 和 floR 是主要的 ARGs，其平均浓度水平分别为 4.51-7.74 拷贝/L 和 5.36-13.07 拷贝/g，表明 ARGs 在没有抗生素使用记录的 RAS 中普遍存在。即使在最终的 UV 处理后，RAS 中的水也发现 ARGs 的水平升高，与进水相比。在 RAS 中，变形菌门、疣微菌门、拟杆菌门和浮霉菌门是主要的门。值得注意的是，与丰富的 ARGs 一起，观察到潜在的机会性病原体的水平升高，这表明捕获 ARGs 和 MGEs 对人类病原体的风险增加。本研究首次揭示了养殖鱼类、其粪便、颗粒饲料作为引入源，以及处理单元的选择作用共同驱动了 ARG 特征，水环境污染因素的共同选择及其随后由其影响诱导的细菌群落变化是 RAS 中 ARG 传播的决定因素。
