Aquatic EcoHealth Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Aquatic EcoHealth Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
Environ Int. 2018 Aug;117:107-115. doi: 10.1016/j.envint.2018.04.045. Epub 2018 May 4.
In freshwater systems, both antibiotic resistance genes (ARGs) and cyanobacterial blooms attract global public health concern. Cyanobacterial blooms can greatly impact bacterial taxonomic communities, but very little is known about the influence of the blooms on antibiotic resistance functional community. In this study, the ARGs in both free-living (FL) and particle-attached (PA) bacteria under bloom and non-bloom conditions were simultaneously investigated in a subtropical reservoir using high-throughput approaches. In total, 145 ARGs and 9 mobile genetic elements (MGEs) were detected. The most diverse and dominant of which (68.93%) were multidrug resistance genes and efflux pump mechanism. The richness of ARGs in both FL and PA bacteria was significantly lower during the bloom period compared with non-bloom period. The abundance of ARGs in FL bacteria was significantly lower under bloom condition than in the non-bloom period, but the abundance of ARGs in PA bacteria stayed constant. More importantly, the resistant functional community in PA bacteria was more strongly influenced by the cyanobacterial bloom than in the FL bacteria, although >96% ARGs were shared in both FL and PA bacteria or both bloom and non-bloom periods. We also compared the community compositions between taxonomy and function, and found antibiotic resistant communities were highly variable and exhibited lower similarity between bloom and non-bloom periods than seen in the taxonomic composition, with an exception of FL bacteria. Altogether, cyanobacterial blooms appear to have stronger inhibitory effect on ARG abundance in FL bacteria, and stronger influence on antibiotic resistant community composition in PA bacteria. Our results further suggested that both neutral and selective processes interactively affected the ARG composition dynamics of the FL and PA bacteria. However, the antibiotic resistant community of FL bacteria exhibited a higher level of temporal stochasticity following the bloom event than PA bacteria. Therefore, we emphasized the bacterial lifestyles as an important mechanism, giving rise to different responses of antibiotic resistant community to the cyanobacterial bloom.
在淡水系统中，抗生素耐药基因 (ARGs) 和蓝藻水华都引起了全球公共卫生关注。蓝藻水华会极大地影响细菌分类群落，但人们对水华对抗生素耐药功能群落的影响知之甚少。在这项研究中，使用高通量方法同时研究了亚热带水库中蓝藻水华和非水华条件下游离 (FL) 和颗粒附着 (PA) 细菌中的 ARGs。总共检测到 145 个 ARGs 和 9 个移动遗传元件 (MGE)。其中最多样和最主要的是多药耐药基因和外排泵机制。FL 和 PA 细菌中 ARGs 的丰富度在水华期明显低于非水华期。FL 细菌在水华条件下的 ARG 丰度明显低于非水华期，但 PA 细菌的 ARG 丰度保持不变。更重要的是，PA 细菌中的耐药功能群落受蓝藻水华的影响比 FL 细菌更强烈，尽管 >96%的 ARGs 在 FL 和 PA 细菌或水华和非水华期之间共享。我们还比较了分类和功能之间的群落组成，发现抗生素耐药群落高度可变，并且在水华期和非水华期之间的相似性低于分类组成，FL 细菌除外。总的来说，蓝藻水华似乎对 FL 细菌中 ARG 丰度有更强的抑制作用，对 PA 细菌中抗生素耐药群落组成有更强的影响。我们的结果进一步表明，中性和选择过程相互作用影响了 FL 和 PA 细菌中 ARG 组成的动态变化。然而，FL 细菌的抗生素耐药群落在水华事件后表现出比 PA 细菌更高的时间随机性。因此，我们强调了细菌生活方式作为一个重要的机制，导致抗生素耐药群落对蓝藻水华的反应不同。
