E.coli临床分离株的基因组结构分型

Genomic typing of clinical isolates of Escherichia coli

目的 通过基因组结构分析对临床分离的Escherichiacoli(E .coli)进行分型 ,并探讨分型与临床疾病的关系。方法 取临床不同疾病病人的痰、尿、血、分泌物等标本 ,分离E .coli。用I CeuⅠ酶切全基因组DNA ,用脉冲场凝胶电泳分离DNA片段后 ,根据酶切图谱的异同进行分型。结果从临床上分离的 6 4株E .coli中 ,6 2株有 7个I CeuⅠ酶切位点 ,2株有 8个I CeuⅠ酶切位点。菌株间I CeuⅠ酶切图谱差异明显。这些菌株根据基因组结构的差异分为 32个型 ,分型与疾病之间的对应关系分散。结论 临床分离的E .coli基因组结构存在多样性 ,其与临床疾病之间的关系有待进一步探讨。

Objective We attempted to resolve different genomic types of clinical isolates of E.coli by analysis of genome structure and investigate the relationships between the genomic types and the kinds of associated diseases. Methods 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- Ceu Ⅰ cleavage pattern. Results Among the 64 clinical isolates identified as E.coli , 62 had 7 I- Ceu Ⅰ sites and two had 8 I- Ceu Ⅰ sites. These bacteria had obviously different genome structures and were divided into 32 genome types. No correlation was found between the genome types of the bacteria and the associated diseases. Conclusion There was a significant diversity in genome structure among the clinical isolates of E.coli . The relationships between the genome types and the associated clinical diseases are not conclusive.