摘要

一个地区人类活动的迅速扩张会加剧抗生素抗性基因（ARGs）诱发的人类健康风险。城市周边生态系统是城乡生态系统之间的共生界面，对城市周边地区ARGs传播的调查提供了一个跟踪ARGs传播和潜在缓解措施的基本框架。在本研究中，通过使用高通量定量PCR和16S rRNA基因高通量测序，ARGs及其宿主细菌群落的季节和地理分布在城郊河流中表征。下游ARGs的丰度比上游高5.2-33.9倍，这表明人类生活区域存在明显的抗生素耐药性污染。根据附近土地利用分类的比较，农田和农村附近样品中ARGs的丰度高于背景值（3.47-5.58倍），表明城郊地区农业和其他人类活动导致河流负荷较高。通过网络分析揭示的共现模式，blaVEB和tetM被认为是ARG在一同模块中聚集的指标。此外，观察到ARG的季节性变化和细菌群落的迁移。还评估了季节温度对流域沿线ARG传播的影响。夏季ARGs绝对丰度最高（平均为2.81×109copies / L），四季ARG丰度趋势与当地气温相似。线性判别分析效应大小（LEfSe）表明九个细菌属可能是相应季节的生物标志物。移动遗传因子（MGEs）与ARGs呈显着正相关（P <0.01），MGEs也是导致ARG改变的关键因素。本研究提供了城市周边地区ARG分布的季节和地理变化概况，并提请注意控制城市周边生态系统中的污染物。

The rapid expansion of human activity in a region can exacerbate human health risks induced by antibiotic resistance genes (ARGs). Peri-urban ecosystems serve at the symbiotic interface between urban and rural ecosystems, and investigations into the dissemination of ARGs in peri-urban areas provide a basic framework for tracking the spread of ARGs and potential mitigations. In this study, through the use of high-throughput quantitative PCR and 16S rRNA gene high-throughput sequencing, seasonal and geographical distributions of ARGs and their host bacterial communities were characterized in a peri-urban river. The abundance of ARGs in downstream was 5.2–33.9 times higher than upstream, which indicated distinct antibiotic resistance pollution in the areas where human lives. With the comparison classified based on land use nearby, the abundance of ARGs in samples near farmland and villages was higher than in the background (3.47–5.58 times), pointing to the high load in the river caused by farming and other human activities in the peri-urban areas. With the co-occurrence pattern revealed by network analysis, blaVEB and tetM were proposed to be indicators of ARGs which get together in the same module. Furthermore, seasonal variations in ARGs and the transport of bacterial communities were observed. The effects of seasonal temperature on the dissemination of ARGs along the watershed was also evaluated. The highest absolute abundance of ARGs occurred in summer (2.81 × 109 copies/L on average), the trends of ARG abundances in four seasons were similar with local air temperature. The Linear discriminant analysis effect size (LEfSe) suggested that nine bacterial genera were implicated as biomarkers for the corresponding season. Mobile genetic elements (MGEs) showed significant positive correlation with ARGs (P < 0.01) and MGEs were also identified as the key-contributing factor driving ARG alteration. This study provides an overview of seasonal and geographical variations in ARGs distribution in a peri-urban river and draws attention to controlling pollutants in peri-urban ecosystems.

https://www.sciencedirect.com/science/article/pii/S0160412017319426