Phylogeny of Shiga toxin-producing Escherichia coli O157 isolated from cattle and clinically ill humans.
Phylogeny of Shiga toxin-producing Escherichia coli O157 isolated from cattle and clinically ill humans.
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DOI：
10.1093/molbev/mss072
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发表时间：
2012-08
影响因子：
10.7
通讯作者：
Clawson ML
中科院分区：
文献类型：
--
作者：
Bono JL;Smith TP;Keen JE;Harhay GP;McDaneld TG;Mandrell RE;Jung WK;Besser TE;Gerner-Smidt P;Bielaszewska M;Karch H;Clawson ML
牛是产生志贺毒素的大肠杆菌O157(STEC O157)的主要宿主，并且含有多种基因亚型，这些亚型并不都与人类疾病有关。STEC O157是从大肠杆菌O55：H7的前体进化而来的；然而，基因组序列的缺乏阻碍了对人和/或牛相关亚型差异的研究。我们的目标是：1)确定STEC O157基因亚型的核苷酸多态；2)使用多态基因和噬菌体插入分型系统确定STEC O157基因亚型的系统发育；3)将本研究中鉴定的多态基因与目前评估STEC O157多样性的金标准-脉冲场凝胶电泳(PFGE)进行比较。利用最初通过189个STEC O157人和牛分离株的全基因组测序鉴定的762个核苷酸多态性，我们对426个STEC O157菌株进行了基因分型。串联多态等位基因定义了175种基因类型，这些基因类型由138个多态组成的最小集合进行标记。确定了STEC O157的八个主要谱系，其中牛是七个的储存库。在这项研究中，牛经常藏匿的两个血统是人类疾病的主要原因，而另一个血统在人类中很少出现，可能已经朝着降低人类毒力的方向进化。值得注意的是，牛并不是已知的大肠杆菌O55：H7或STEC O157：H−(STEC O157血清组中第一个分化的谱系)的宿主，这两种疾病都会导致人类疾病。这一结果令人质疑牛最初是如何感染STEC O157的。通过BlnI和XbaI酶切鉴定的93个菌株亚群中，本研究中鉴定的多态衍生的基因类型没有超过PFGE多样性。然而，我们的结果表明，它们在评估流行病学上无关的STEC O157基因亚型的进化相关性方面是非常有效的，包括那些与牛宿主和人类疾病相关的亚型。
Cattle are a major reservoir for Shiga toxin-producing Escherichia coli O157 (STEC O157) and harbor multiple genetic subtypes that do not all associate with human disease. STEC O157 evolved from an E. coli O55:H7 progenitor; however, a lack of genome sequence has hindered investigations on the divergence of human- and/or cattle-associated subtypes. Our goals were to 1) identify nucleotide polymorphisms for STEC O157 genetic subtype detection, 2) determine the phylogeny of STEC O157 genetic subtypes using polymorphism-derived genotypes and a phage insertion typing system, and 3) compare polymorphism-derived genotypes identified in this study with pulsed field gel electrophoresis (PFGE), the current gold standard for evaluating STEC O157 diversity. Using 762 nucleotide polymorphisms that were originally identified through whole-genome sequencing of 189 STEC O157 human- and cattle-isolated strains, we genotyped a collection of 426 STEC O157 strains. Concatenated polymorphism alleles defined 175 genotypes that were tagged by a minimal set of 138 polymorphisms. Eight major lineages of STEC O157 were identified, of which cattle are a reservoir for seven. Two lineages regularly harbored by cattle accounted for the majority of human disease in this study, whereas another was rarely represented in humans and may have evolved toward reduced human virulence. Notably, cattle are not a known reservoir for E. coli O55:H7 or STEC O157:H− (the first lineage to diverge within the STEC O157 serogroup), which both cause human disease. This result calls into question how cattle may have originally acquired STEC O157. The polymorphism-derived genotypes identified in this study did not surpass PFGE diversity assessed by BlnI and XbaI digestions in a subset of 93 strains. However, our results show that they are highly effective in assessing the evolutionary relatedness of epidemiologically unrelated STEC O157 genetic subtypes, including those associated with the cattle reservoir and human disease.
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影响因子：
4.4
作者：
Bono, JL;Keen, JE;Laegreid, WW
通讯作者：
Laegreid, WW
树突镜：大型系统发育树的互动观众。
影响因子：
3
作者：
Huson, Daniel H.;Richter, Daniel C.;Rausch, Christian;Dezulian, Tobias;Franz, Markus;Rupp, Regula
通讯作者：
Rupp, Regula
影响因子：
2.8
作者：
Gerner-Smidt, P.;Hise, K.;Swaminathan, B.
通讯作者：
Swaminathan, B.
影响因子：
9.4
作者：
GUNZER, F;BOHM, H;KARCH, H
通讯作者：
KARCH, H
影响因子：
4.4
作者：
Bielaszewska, M;Prager, R;Karch, H
通讯作者：
Karch, H