中文摘要：

为了解流经我国城市的典型河流中CTX-M型耐药基因的分布情况及基因变异的多态性现状，进而为科学预防和避免抗生素耐药性的产生和传播提供生态学理论支持，采集我国东部6条典型河流流经城市区段的水样，采用宏基因组学技术与限制性酶切片段多态性分析（RFLP）技术相结合对质粒宏基因组PCR产物进行了分析，并将数据进行生态学统计处理．结果显示CTX—M三种亚型的基因群落在调查中的6条河流均有分布，且都保持了较高的均匀度（E≥0．9298），亚型1中分布于长江水体的基因群落具有明显高于其他河流和平均值的多样性（H’=2．4774）和物种优势度（D=0．9107），而亚型2、3N多样性和优势度最高值则均出现在黄河水体中；松花江与海河之间的群落相似性最高，达到0．8062，而黄河与珠江基凶群落之间的相异性则达到了0．5800．说明在调查中采样的6条河流中均分布着结构稳定且基因优势突出的CTX—M型耐药基因，已对水体生态安全构成了隐患，需要结合进一步研究对其进行防治，以避免耐药基因以质粒为媒介向其他微生物传播造成抗生素耐药性扩散。图3表2参28

英文摘要：

In order to understand the distribution of CTX-M type resistance genes and their variation diversity from the typical city rivers, so as to avoid the generation and dissemination of antibiotic resistance, we investigated six rivers in China. Water samples were collected from six typical rivers in eastern China, then metagenomics idea combined with restriction fragment length polymorphism （RFLP） technology were employed for PCR products assay. All data were processed by ecological statistics. All of six surveyed rivers were distributed with the three subtypes of CTX-M genes with a high evenness （E 〉 0.9298）. For genotype 1, the gene communities from the Yangtze River had a significantly higher diversity （H＇ = 2.4774） and species dominance （D = 0.9107） than in other rivers and the average, while the highest diversity and dominance value of genotype 2 and 3 appeared in the waters of the Yellow River. The gene community similarity between the Sungari and the Haihe was the highest, reaching 0.806 2, while the dissimilarity between the gene communities in the Yellow River and the Pearl River reached 0.580 0. The CTX-M resistance gene communities and plasmid metagenomic showed stable structures as well as prominent dominances in six sampled rivers, which is a threat to ecological safety of water bodies. Further researches are needed for controlling and avoiding the spread of resistant genes to other micro-organisms mediated by plasmid and causing diffusion of antibiotic resistance.