新现食品源非典型肠致病大肠埃希氏菌遗传进化及毒力变异机制

非典型肠致病大肠埃希氏菌（aEPEC,bfp-）是近年来新现的一种重要病原菌，在全球多个国家引起腹泻疾病的暴发流行，且发病率呈上升趋势。由于标准检测方法的限制，我国目前仍缺乏系统的食品源aEPEC流行特征数据。国际公开数据库中aEPEC全基因组信息极少，其进化来源和毒力变异机制尚不清晰。本项目拟在前期已系统收集我国不同地区食品aEPEC菌株的基础上，进一步完善菌株分子血清型、耐药谱和生化谱等基础数据。通过全基因组测序和比较基因组学分析，明确不同aEPEC流行株基因组差异和毒力岛变异规律，揭示其系统发育关系及进化来源；通过对不同毒力菌株RNA-seq转录组测序分析，结合基于单核苷酸多态性（SNP）的毒力表型全基因组关联分析（GWAS），解析其毒力分化和变异机制。本研究将从多维度揭示aEPEC的进化过程，形成对其遗传进化和毒力变异机制的新见解，为我国aEPEC防控提供理论参考。

Atypical enteropathogenic Escherichia coli (aEPEC, bfp-) is an emerging pathogen worldwide. In recent years, outbreaks of diarrhoea caused by aEPEC have increased significantly. Nevertheless, due to the limitation of detection methods, there is scarce information on the epidemiological characteristics of food-borne aEPEC strains. Until now, whole-genome sequence of aEPEC deposited in the international database is insufficiency. No systematic study has been carried out on the evolution and virulence variation mechanism of aEPEC. This project aims to replenish the epidemiological data of food-borne aEPEC isolated from different regions of China, and explore the genomic differences and pathogenicity island of aEPEC strains based on whole-genome sequencing and comparative genomic analysis. The phylogenetic relationship and evolutionary source of aEPEC will be further clarified. Through transcriptome sequencing (RNA-seq) and comparative transcriptome analysis, the virulence differentiation and variation mechanism will be analyzed, combined with genome-wide association study (GWAS) of virulence phenotype based on single nucleotide polymorphism (SNP). This study will provide an innovative insight into the genetic evolution and virulence variation mechanism of aEPEC, and offer significant basic data for prevention and control of aEPEC infection.