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目的对Gen Bank的1620株大肠埃希菌基因组中儿童脑膜炎大肠埃希菌毒力基因ibeC的分布进行研究。方法下载Gen Bank现存并公开释放的1620株大肠埃希菌基因组数据,构建数据库,通过序列比对程序BLAST查找分析各菌株携带ibeC情况,使用Clustal X1.83软件对大肠埃希菌代表菌株的ibeC基因序列进行多序列比对。同时应用多位点序列分型方法(multi locus sequence typing,MLST)对1620株大肠埃希菌菌株的分布特点进行分析。用Bio Numerics V4.0软件,对342株不同来源、不同致病性代表菌株及MLST数据库中已经明确分群的72株大肠埃希菌菌株的不同ST型别构建最小生成树,分析菌株之间的种群结构。结果 1620株大肠埃希菌基因组中全部携带ibeC基因,ibeC序列平均相似值为98.21%,MLST将1620株大肠埃希菌菌株分成261个已知ST型,ECOR菌株共有49个ST型别,菌株ST型别与菌株来源关联性不强,不同来源、不同致病型别的菌株分布在不同家系。结论 ibeC基因广泛分布在各类大肠埃希菌中,脑膜炎相关大肠埃希菌与其他致病型大肠埃希菌所携带ibeC基因差异微小,菌株MLST聚类分析显示所有菌株分布广泛,来源复杂,进一步说明ibeC基因非常保守。
Objective To study the distribution of ibeC gene in Escherichia coli in children from 1620 Escherichia coli genomes in Gen Bank. Methods Genomic data of 1620 Escherichia coli strains released by Gen Bank were downloaded and used to construct a database. The sequences of ibeC in each strain were analyzed by BLAST sequence alignment. The ibeC of Escherichia coli strains was analyzed by Clustal X1.83 software. Multiple sequence alignment of gene sequences. At the same time, the distribution characteristics of 1620 Escherichia coli strains were analyzed by multi locus sequence typing (MLST). Using Bio Numerics V4.0 software, the minimum spanning tree was constructed on different St types of 72 strains of Escherichia coli isolated from 342 strains of different origin, different pathogenicity, and MLST database. Population structure. Results The ibeC gene was carried in 1620 Escherichia coli genomes. The average similarity of ibeC sequences was 98.21%. MLST divided 1620 Escherichia coli strains into 261 known ST genotypes. There were 49 ST genotypes in ECOR strains, ST type and the origin of the strain is not strong, different sources, different pathogenic strains were distributed in different families. Conclusion The ibeC gene is widely distributed in all kinds of Escherichia coli, meningitis-related Escherichia coli and other pathogenic Escherichia coli ibeC gene is very small, MLST cluster analysis showed that all strains are widely distributed, complex source , Further illustrating that the ibeC gene is very conserved.