大肠埃希菌基因组结构分型及其与疾病关系的研究

Relationship between Genome Types and Clinical Diseases of Escherichia coli

目的通过研究大肠埃希菌的基因组结构并分型,探讨分型与临床疾病之间的关系.方法取临床不同疾病患者的痰、尿、血、分泌物等标本,分离大肠埃希菌62株,经I-CeuⅠ酶切全基因组DNA、脉冲场凝胶电泳分离片段,按酶切图谱的异同进行分型.结果 62株大肠埃希菌基因组结构中,均有7个I-CeuⅠ酶切位点,表明有7个rrn操纵子.基因组大小在4 500～5 000 kb之间.根据基因组结构细微差别分为30个型.结论临床分离大肠埃希菌基因组结构存在多样性,基因组结构分型与临床疾病之间有一定的对应关系.

Objective To resolve different genomic types of clinical isolates of Escherichia coli （E. coli） by analysis of gehome structure and investigate the relationships between the genomic types and the kinds of associated diseases. Methods Sixty-two E. coli strains were isolated from hospitalized patients with different kinds of infections. Intact bacterial genomic DNA was isolated in agarose blocks and cleaved with I-Ceu Ⅰ. After separation of the fragments by pulsed field gel electrophoresis （PFGE）, cleavage patterns of the genomic DNA were compared among the bacteria and the clinical isolates were divided into different genomic types based on their similarities in the I-CeuⅠ cleavage pattern. Results The structures of 62 E. coli strains all had 7 I-CeuⅠ sites, yielded 7 fragments, indicating 7 rrn operons in the genomes. The size was from 4 500 kb to 5 000 kb. According to the differences and similarities of structures, 62 E. coli strains were classified into 30 genome types. Conclusion There was a significant diversity in genome structures among different clinical isolates of E. coli. There was some parallelism relationship between the genome types and clinical diseases.