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首页> 外文期刊>Journal of Clinical Microbiology >Clinical Escherichia coli Strains Carrying stx Genes: stx Variants and stx-Positive Virulence Profiles
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Clinical Escherichia coli Strains Carrying stx Genes: stx Variants and stx-Positive Virulence Profiles

机译：携带stx基因的临床大肠杆菌菌株：stx变异体和stx阳性毒力谱

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Altogether, 173 Shiga toxin-producing Escherichia coli (STEC) serotype O157 (n = 111) and non-O157 (n = 62) isolates from 170 subjects were screened by PCR-restriction fragment length polymorphism for eight different stx genes. The results were compiled according to serotypes, phage types of O157, production of Stx toxin and enterohemolysin, and the presence of eae. The stx genes occurred in 11 combinations; the most common were stx2 with stx2c (42%), stx2 alone (21%), and stx1 alone (16%). Of the O157 strains, 64% carried stx2 with stx2c versus 2% of the non-O157 strains (P < 0.001). In the non-O157 strains, the prevailing gene was stx1 (99% versus 1% in O157 strains; P < 0.001). In addition, one strain (O Rough:H4:stx2c) which has not previously been described as associated with hemolytic-uremic syndrome (HUS) was found. Ten stx-positive virulence profiles were responsible for 71% of all STEC infections. Of these profiles, five accounted for 71% of the 21 strains isolated from 20 patients with HUS or thrombotic thrombocytopenic purpura (TTP). The strains having the virulence profile that caused mainly HUS or TTP or bloody diarrhea produced Stx with titers of ≥1:128 (90%) more commonly than did other strains (51%; P < 0.001). These strains were also more commonly enterohemolytic (98% versus 68% for other strains; P < 0.001) and possessed the eae gene (100%) more commonly than did other strains (74%; P < 0.001). A particular virulence profile, O157:H7:PT2:stx2:stx2c:eae:Ehly, was significantly more frequently associated with HUS and bloody diarrhea than were other profiles (P = 0.02) and also caused the deaths of two children. In this study, the risk factors for severe symptoms were an age of <5 years and infection by the strain of O157:H7:PT2 mentioned above.
机译：共有173种产志贺毒素的大肠杆菌（STEC）血清型O157（ n = 111）和非O157（ n = 62）分离株通过PCR-限制性片段长度多态性从170个受试者中筛选出八个不同的 stx 基因。根据血清型，O157的噬菌体类型，Stx毒素和肠溶血素的产生以及 eae 的存在对结果进行汇编。 stx 基因以11种组合出现。最常见的是 stx 2 和 stx 2c （42％）， stx 单独 2 （21％），单独s tx 1 （16％）。在O157菌株中，有64％携带 stx 2 和 stx 2c ，而非O157菌株携带2％ （ P <0.001）。在非O157菌株中，主要基因是s tx 1 （O157菌株中99％比1％; P <0.001）。另外，发现了一种以前没有被描述为与溶血性尿毒症综合征（HUS）有关的菌株（O Rough：H4： stx 2c ）。十个 stx 阳性毒力谱负责所有STEC感染的71％。在这些特征中，从20例HUS或血栓性血小板减少性紫癜（TTP）患者中分离出的21株菌株中，有5株占71％。具有主要导致HUS或TTP或血性腹泻的毒力的菌株比其他菌株（51％; P <0.001）产生的Stx效价≥1：128（90％）的情况更为常见。这些菌株还具有更强的肠溶血性（98％，其他菌株为68％; P <0.001），并且具有 ea 基因（100％）的频率高于其他菌株（74％; P <0.001）。特定的毒力特征O157：H7：PT2： stx 2 ： stx 2c ： eae < / em>：Ehly与HUS和血性腹泻相关的发生率明显高于其他情况（ P = 0.02），还造成了两个孩子的死亡。在这项研究中，严重症状的危险因素是年龄小于5岁且被上述O157：H7：PT2菌株感染。

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