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目的分析并找出肠致病性大肠杆菌Deng(Enteropathogenic Escherichia coli Deng,EPEC Deng)的全基因组序列特点。方法 EPEC Deng来源于我国婴幼儿腹泻患者的粪便标本,菌株采用诊断血清鉴定血清型,通过自动细菌鉴定仪,使用微量肉汤法进行药敏试验。进一步提取细菌总DNA,构建测序文库,通过Illumina 2000仪器测序,然后利用多引物PCR等方法进行补缺口及拼接,最终获得完整的全基因组。采用相关软件获得基因序列,通过对比已知的蛋白数据库进行基因功能注释及生物信息学分析。结果 EPEC Deng菌株归属O119:H6,药敏结果显示该菌株对环丙沙星、左氧氟沙星、氨苄西林及氨苄西林/舒巴坦耐药,对其余的抗菌药物均敏感。EPEC Deng基因组包含5 233 046 bp,GC含量50.48%。基因组通过注释后总共有5 347个编码蛋白序列,80个t RNA的编码基因,以及22个完整的r RNA基因编码的操纵子。EPEC染色体基因组中含有致病岛,大小约为40Kb左右,与数据库中的一个37Kb的致病岛(AF200363.1)序列极为相似,相似度达到99%。结论完成了肠致病性大肠杆菌基因组精细测序分析,PAI是EPEC致病的关键,为进一步研究菌株的进化关系提供了基因数据。
Objective To analyze and identify the genome-wide sequence of enteropathogenic Escherichia coli Deng (EPEC Deng). Methods EPEC Deng was derived from stool samples from infants and young children with diarrhea in our country. The strains were identified by serodiagnosis and drug sensitivity test by micro-broth method. Further extraction of total bacterial DNA, construction of sequencing libraries, sequencing by Illumina 2000 instrument, and then using multi-primer PCR and other methods to fill the gap and splicing, and ultimately obtain the complete genome. The related software was used to obtain the gene sequence. Gene function annotation and bioinformatics analysis were performed by comparing known protein databases. Results The EPEC strain was assigned to O119: H6. The susceptibility test showed that the strains were resistant to ciprofloxacin, levofloxacin, ampicillin and ampicillin / sulbactam, and were sensitive to the other antibiotics. The genome of EPEC Deng contains 5 233 046 bp with a GC content of 50.48%. After the genome was annotated a total of 5 347 encoded protein sequences, 80 tRNA encoding genes, and 22 complete rRNA gene encoding operon. The genome of EPEC contains the pathogenic island with a size of about 40Kb, which is very similar to the sequence of a 37Kb virulent island (AF200363.1) in the database with a similarity of 99%. Conclusion The genome sequencing of enteropathogenic Escherichia coli has been completed. PAI is the key factor in the pathogenesis of EPEC, and provides gene data for further study on the evolutionary relationship of the strains.