长江下游某水源型水库抗生素抗性基因污染研究

Study on antibiotic resistance genes contamination in a reservoir located at Yangtze River downstream

抗生素抗性基因是水环境中的新型污染物.为了探究夏季时期长江下游某水源型水库抗生素抗性基因(Antibiotic Resistance Genes,ARGs)污染赋存特征,分别采集了水体和沉积物样本并使用高通量荧光定量PCR和实时荧光定量PCR进行研究.结果表明,长江下游水体中检测出104种ARGs,水库水体中检测出118种ARGs,沉积物中检测出124种ARGs.β-内酰胺类、多重抗药类、其他类共54种ARGs为水库中占主导的抗性基因.抗性基因绝对丰度在水体中呈现从长江下游到库内富集的趋势,这表明水环境中的ARGs在水库中富集;相对丰度特征呈现长江下游水介质与库内水介质聚类,水介质与沉积物介质聚类.水体样本的整合子(CintⅠ-1(class 1)、intⅠ-1(clinical))与其ARGs总量之间存在显著的相关性(r=0.750,p<0.05;r=0.971,p<0.05),说明整合子对ARGs转移和富集具有重要作用.

Antibiotic resistance genes（ ARGs） are known as emerging contaminations in the aquatic environment. In order to explore the levels of ARGs contaminations in a reservoir downstream of the Yangtze River during summer,water and sediment samples were collected and analysed using high throughput quantitative PCR（ HT-q PCR） and real-time quantitative PCR（ RT-q PCR）. The results show that 104,118 and 124 ARG targets were detected positive in the lower reaches of the Yangtze River,reservoir and sediment respectively. β-lactamase genes,multidrug resistance genes and 54 other kinds of ARGs were identified to be the dominant genes in the reservoir. The absolute abundances of the ARGs in the reservoir were found to be higher than that in the lower reaches of Yangtze River,which indicates an accumulation of ARGs in the reservoir. A heatmap with cluster analysis on the relative ARGs abundance shows clustering between the lower reaches of the river and the reservoir,and between the water columns and the sediment.Relative abundances of integrons（ CintⅠ-1（ class 1）,intⅠ-1（ clinical）） are significantly correlated to the levels of total ARGs（ r = 0. 750,p 〈 0. 05; r =0.971,p〈0.05）,which elucidates that integrons can play an important role in ARGs transfer and accumulation.