摘要

    在整个水生环境中抗生素抗性基因（ARG）的广泛出现引起了全球对公共卫生的关注，但是对ARGs在各种环境介质中的出现和传播的了解仍然有限。本研究调查了从太湖分离出的蓝细菌中六类ARGs的发生和时空格局。四环素和磺酰胺抗性基因被确定为主要的ARG。蓝细菌在开花期的ARGs含量显着高于非开花期。 ARGs在细胞外DNA（eDNA）中的贡献和持久性高于蓝细菌的细胞内DNA（iDNA）。携带蓝细菌的eDNA携带ARG在较低温度下更稳定。太湖蓝藻水华的主要属微囊藻和球菌中的ARGs的相对丰度显着高于其他蓝藻菌株。温度和蓝细菌细胞浓度的升高促进了蓝细菌中ARGs细菌同化的共轭转移效率。我们的结果表明，蓝藻可以作为在水生环境中获取和传播ARG的重要储库和来源，因此扩大了蓝藻水华负面生态影响的定义。

    The widespread occurrence of antibiotic resistance genes (ARGs) throughout aquatic environments has raised global concerns for public health, but understanding of the emergence and propagation of ARGs in diverse environmental media remains limited. This study investigated the occurrence and spatio-temporal patterns of six classes of ARGs in cyanobacteria isolated from Taihu Lake. Tetracycline and sulfonamide resistance genes were identified as dominant ARGs. The abundance of ARGs in cyanobacteria was significantly higher in the bloom period than in the non-bloom period. The contribution and persistence of ARGs were higher in extracellular DNA (eDNA) than in intracellular DNA (iDNA) from cyanobacteria. Cyanobacteria-associated eDNA carrying ARGs was more stable at lower temperature. The relative abundances of ARGs in Microcystis and Synechococcus, the dominant genera of cyanobacterial blooms in Taihu Lake, were significantly higher than those in other cyanobacterial strains. The conjugative transfer efficiency for bacterial assimilation of ARGs in cyanobacteria was facilitated by increasing temperature and cyanobacterial cell concentration. Our results demonstrated that cyanobacteria could act as a significant reservoir and source for the acquisition and dissemination of ARGs in aquatic environments, hence the definition of negative ecological effects of cyanobacterial blooms was expanded.

    https://www.sciencedirect.com/science/article/pii/S0160412020319899