达托霉素是临床治疗中抵御万古霉素耐药肠球菌的“最后一道防线”，然而前期研究从市售生鲜猪肉中分离出多株达托霉素耐药肠球菌，这提示我国应及早防控其在食物链中的传播。因此，本项目以解析达托霉素耐药肠球菌在食物链中传播的遗传基础为目标。在从环境、养殖动物、人群、市售肉类和果蔬中分离达托霉素耐药及临界耐药肠球菌的基础上，通过基因组测序和基因功能注释界定肠球菌核心和附属基因组组成，采用比较基因组和基因组SNP分型技术，分析达托霉素耐药（临界耐药）肠球菌大量关键基因或位点的遗传多态性，阐述食物链源达托霉素耐药（临界耐药）肠球菌的系统发育关系，探究耐药株传播的基因基础，探讨临界耐药株与生境相关的耐药转归趋势，为发展先进的链条污染阻断技术奠定理论基础。

As an antibiotic, daptomycin (DAP), frequently used as the “last resort” to against vancomycin-resistant Enterococcus. However, our preliminary studies have showed that DAP-resistance Enterococcus can been found and isolated from retailed fresh pork, which reminds people to prevent and control the widespread of DAP-resistant species in food chain of China. Therefore, the aim of present study is analyzing the genetic basis of DAP-resistance Enterococcus spreading in food chain. On the basis of isolate DAP-resistance (or critical resistance) Enterococcus, which are from environment, livestock, crowds, retailed meat, fruits and vegetables, the core genome and accessory genome of Enterococcus, will be determined under the help of genomic sequencing and genome annotation. Using comparative genome and genomic SNP (single nucleotide polymorphism) typing technology, the genetic polymorphism of a large amount of key genes and sites of DAP-resistance Enterococcus will be analyzed. And then, the phylogenetic relationships of DAP-resistance (or critical resistance) Enterococcus in food chain will be elaborated, and the genetic basis of resistant strains will be discussed. Furthermore, it will be explored that the turnover trend of critical DAP-resistance Enterococcus related to their living biotope. This study is going to lay a theoretical foundation to develop advanced chain pollution blocking technology.