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首页> 外文期刊>Applied Microbiology >Sequence Variability of P2-Like Prophage Genomes Carrying the Cytolethal Distending Toxin V Operon in Escherichia coli O157
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Sequence Variability of P2-Like Prophage Genomes Carrying the Cytolethal Distending Toxin V Operon in Escherichia coli O157

机译：在大肠杆菌O157中携带细胞致死性毒素V操纵子的P2-like噬菌体基因组的序列变异性

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Cytolethal distending toxins (CDT) are potent cytotoxins of several Gram-negative pathogenic bacteria, including Escherichia coli , in which five types (CDT-I to CDT-V) have been identified so far. CDT-V is frequently associated with Shiga-toxigenic E. coli (STEC), enterohemorrhagic E. coli (EHEC) O157 strains, and strains not fitting any established pathotypes. In this study, we were the first to sequence and annotate a 31.2-kb-long, noninducible P2-like prophage carrying the cdt-V operon from an stx - and eae -negative E. coli O157:H43 strain of bovine origin. The cdt-V operon is integrated in the place of the tin and old phage immunity genes (termed the TO region) of the prophage, and the prophage itself is integrated into the bacterial chromosome between the housekeeping genes cpxP and fieF . The presence of P2-like genes ( n = 20) was investigated in a further five CDT-V-positive bovine E. coli O157 strains of various serotypes, three EHEC O157:NM strains, four strains expressing other variants of CDT, and eight CDT-negative strains. All but one CDT-V-positive atypical O157 strain uniformly carried all the investigated genomic regions of P2-like phages, while the EHEC O157 strains missed three regions and the CDT-V-negative strains carried only a few P2-like sequences. Our results suggest that P2-like phages play a role in the dissemination of cdt-V between E. coli O157 strains and that after integration into the bacterial chromosome, they adapted to the respective hosts and became temperate.
机译：细胞致死性扩张性毒素（CDT）是几种革兰氏阴性致病菌（包括大肠杆菌）的有效细胞毒素，迄今为止已鉴定出五种类型（CDT-1至CDT-V）。 CDT-V通常与志贺毒素性大肠杆菌（STEC），肠出血性大肠杆菌（EHEC）O157菌株以及不符合任何已确定病态的菌株相关。在这项研究中，我们是第一个对31.2 kb长，不可诱导的P2样噬菌体进行测序和注释的载体，该噬菌体带有来自牛源性stx和eae阴性大肠杆菌O157：H43菌株的cdt-V操纵子。 cdt-V操纵子被整合到原噬菌体的锡和旧噬菌体免疫基因（称为TO区域）的位置，并且原噬菌体本身被整合到管家基因cpxP和fieF之间的细菌染色体中。在另外五种不同血清型CDT-V阳性牛大肠杆菌O157菌株，三株EHEC O157：NM菌株，四株表达CDT其他变体的菌株和八株CD2-V阳性牛大肠杆菌O157菌株中研究了P2样基因的存在（n = 20）。 CDT阴性菌株。除了一个CDT-V阳性非典型O157菌株，所有菌株均均匀地携带了所有P2样噬菌体的基因组区域，而EHEC O157菌株则缺失了三个区域，而CDT-V阴性的菌株仅携带了几个P2样序列。我们的结果表明，P2样噬菌体在大肠杆菌O157菌株之间的cdt-V传播中起作用，并且在整合入细菌染色体后，它们适应了各自的宿主并变得温带。

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