Objective: To investigate the association between phage-mediated shiga toxin and molecular distribution of CRISPR in Escherichia (E.) coli O26∶H11 or NM. Methods: A total of 135 E. coli O26 ∶ H11 or NM strains were collected from NCBI database. Software CRT and CRISPR Finder were used to extract CRISPR and Excel was used to assign the spacer of unique number and type CRISPR. And the relationship between CRISPR and stx phage was analyzed. Results: All the 135 E. coli O26 ∶ H11 or NM strains had the CRISPR. For CRISPR1, CRISPR2.1, CRISPR2.2 and CRISPR3-4, 19, 22, 1 and 1 subtypes were found, respectively. According to the four CRISPR sites, the strains could be divided into 40 subtypes. Stx-phage was only observed in the group C of CRISPR. Compared with E. coli of stx-phage negative, E. coli with stx-phage harbored more spacers. Conclusions: CRISPR loci was extensively existed in E. coli O26∶H11 or NM, and many subtypes were found in these strains. The presence of stx-phage was related to the molecular distribution of CRISPR in E. coli O26∶H11 or NM. CRISPR might be a valuable biomarker to identify strains with high virulent potential.
目的： 探讨O26∶H11及NM血清型大肠埃希菌中成簇规律间隔短回文重复序列（CRISPR）的分子分布特征及其与stx噬菌体的关系。 方法： 135株O26∶H11及NM血清型大肠埃希菌从NCBI数据库获取，利用CRT软件及CRISPR Finder提取CRISPR信息，并用Excel软件对间隔序列进行编号及分析CRISPR亚型，并分析CRISPR与stx噬菌体之间的关系。 结果： 135株O26∶H11及NM血清型大肠埃希菌中均存在CRISPR结构，CRISPR1包括19个亚型，CRISPR 2.1包括22个亚型，CRISPR2.2包括1个亚型，CRISPR3-4包括1个亚型。stx噬菌体在CRISPR群组C中出现，stx(+)菌株比stx(-)菌株拥有更多的间隔序列。 结论： CRISPR位点在O26∶H11或NM血清型大肠埃希菌中广泛存在，且存在着不同的亚型，stx噬菌体与CRISPR的分子分布特征有关，可能作为鉴定高毒菌株的分子靶标。.
Keywords: Clustered regularly interspaced short palindromic repeat; Escherichia coli; Stx phage.