分流制雨水管网沉积物中典型抗生素抗性基因污染特性

The pollution characteristics of typical antibiotic resistance genes in separate rainwater pipe network sediments

针对城市雨水管网沉积物中抗生素抗性基因(ARGs)污染特性尚不清楚的问题,本研究选择南京江北新区3种不同功能区(文教区、交通区及商业区)分流制雨水管网沉积物作为研究对象,考察了各功能区雨水管网沉积物中细菌耐药性,分析了β⁃内酰胺类和四环素类两类典型ARGs的组成种类及其相对丰度差异,重点探讨了上述典型ARGs在不同粒径颗粒中的分布特征.结果表明,各功能区可培养细菌总数大小顺序为商业区>文教区>交通区,而携带典型ARGs的耐药菌(ARB)相对含量大小顺序却为文教区>商业区>交通区;交通区的典型ARGs相对丰度高于文教区和商业区1个数量级;随着干期长度的增加,各功能区雨水管网沉积物中典型ARGs种类及相对丰度均有不同程度的减少;随着颗粒粒径的减小,文教区雨水管道沉积物中典型ARGs的丰度变化不大,交通区的雨水管道沉积物中典型ARGs的丰度则呈增加趋势,而商业区的无明显规律;粒径较小的颗粒中可移动遗传因子(MGEs)对ARGs的分布影响更大,且以<75μm粒径段颗粒中的最明显(相关系数为0.874).

In this study,three different functional areas(education area,traffic area,and commercial area)from Nanjing Jiangbei New District were selected as research objects,in order to pollution characteristics of antibiotic resistance genes(ARGs)in urban separate rainwater pipe network sediments.Bacterial resistance of rainwater pipe network sediments in the different functional areas was investigated.Both composition and relative abundance about two typical ARGs includingβ⁃lactam and tetracycline were also analyzed.The emphasis was placed on distribution characteristics of typical ARGs in particles with different sizes.Results showed that the order of cultured bacteria number was as follows:commercial area>education area>traffic area,whilst the relative content of antibiotic resistance bacteria carrying typical ARGs was in the order of education area>commercial area>traffic area.The relative abundance of typical ARGs in the traffic area was one order of magnitude higher than that in the education area and commercial area.Both species and relative abundance of typical ARGs in the rainwater pipe network sediments had the varying decreases with the increase of dry periods.As the particle size decreased,the relative abundance of typical ARGs in rainwater pipe network sediments from the educational area change weakly,but the one from the traffic area had an increasing trend,and there was no obvious change tendency for the commercial area.The impact of mobile genetic elements in the small particle on ARGs distribution was greater,and the largest was particles with sizes less than 75μm(0.874 of correlation coefficient).