摘要

       以往对环境抗生素抗性基因（ARGs）的研究主要集中在污水处理厂、水产养殖和畜牧养殖场等污染源上，很少在河流集水区等区域范围内解决这个问题。因此，从北江源头至河口的38个地点采集的地表水样品中，对23种ARGs的发生和丰度进行了调查。其中，在该区域频繁检测到 11 个 ARG，选择 5 个 ARG（sulI、sulII、tetB、tetC 和 tetW）进行分布模式分析。所选 ARG 的丰度在上游（8.70 × 106 拷贝/ ng DNA）和下游（3.17 × 106 拷贝/ ng DNA）高于中游区域（1.23 × 106 拷贝/ ng DNA），这是与人口密度和污染源数量呈正相关。北江沿岸ARGs的污染源不仅对其丰度和多样性有很大影响，而且对水样中特定ARGs的分布也有很大影响。 sulI 和 sulII 均可能来源于水产养殖场和动物养殖场，tetW 基因可能与采矿/金属冶炼业和电子废物处理有关，tetC 基因常见于多污染源地区。然而，tetB 的丰度与人为影响并不特别相关。这些发现突出了污染源和人口密度对区域范围内 ARGs 分布和传播的影响。

       Previous studies on environmental antibiotics resistance genes (ARGs) have focused on the pollution sources such as wastewater treatment plants, aquaculture and livestock farms, etc. Few of them had addressed this issue in a regional scale such as river catchment. Hence, the occurrence and abundances of 23 ARGs were investigated in surface water samples collected from 38 sites which located from the river source to estuary of the Beijiang River. Among them, 11 ARGs were frequently detected in this region and 5 ARGs (sulI, sulII, tetB, tetC, and tetW) were selected for their distribution pattern analysis. The abundances of the selected ARGs were higher in the upstream (8.70 × 106 copies/ng DNA) and downstream areas (3.17 × 106 copies/ng DNA) than those in the midstream areas (1.23 × 106 copies/ng DNA), which was positively correlated to the population density and number of pollution sources. Pollution sources of ARGs along the Beijiang River not only had a great impact on the abundances and diversity, but also on the distribution of specific ARGs in the water samples. Both sulI and sulII were likely originated from aquaculture farms and animal farms, tetW gene was possibly associated with the mining/metal melting industry and the electric waste disposal and tetC gene was commonly found in the area with multiple pollution sources. However, the abundance of tetB was not particularly related to anthropogenic impacts. These findings highlight the influence of pollution sources and density of population on the distribution and dissemination of ARGs at a regional scale.

https://www.sciencedirect.com/science/article/abs/pii/S100107421730606X