Distribution of espM and espT among enteropathogenic and enterohaemorrhagic Escherichia coli.
Distribution of espM and espT among enteropathogenic and enterohaemorrhagic Escherichia coli.
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DOI：
10.1099/jmm.0.010231-0
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发表时间：
2009-08
影响因子：
3
通讯作者：
Frankel G
中科院分区：
文献类型：
--
作者：
Arbeloa A;Blanco M;Moreira FC;Bulgin R;López C;Dahbi G;Blanco JE;Mora A;Alonso MP;Mamani RC;Gomes TAT;Blanco J;Frankel G
肠出血性大肠杆菌（EHEC）和肠致病性大肠杆菌。大肠杆菌（EPEC）易位数十种III型分泌系统效应物，包括激活Rho GTP酶的WxxxE效应物Map、EspM和EspT。虽然LEE致病岛上携带的图谱在EPEC和EHEC菌株中是绝对保守的，但espM和espT的流行率尚不清楚。在这里，我们报告的结果，旨在确定espM和espT之间的临床EPEC和肠出血性大肠杆菌分离株的患病率大屏幕。结果表明，在51%的测试菌株中检测到的espM更常见于与严重人类感染相关的EPEC和EHEC血清群中。 相反，espT在所有EHEC分离株中均不存在，仅在1.8%的受试EPEC菌株中发现。 对espT阳性菌株的毒力基因库的进一步表征导致鉴定了一种新的β 2紧密连接蛋白变体。除两株外，所有espT阳性菌株均含有tccP基因。espT首先在啮齿类柠檬酸杆菌中发现，后来在EPEC E110019中通过计算机模拟发现，这是特别令人感兴趣的，因为该菌株是1987年芬兰特别严重的腹泻暴发的原因，该暴发影响了学校综合体中的650人和另外137名相关家庭成员。将EspT的蛋白质序列与E110019的蛋白质序列进行比较显示出高水平的保守性，只有三个菌株编码的EspT在6个氨基酸上不同。目前尚不清楚espT为何如此罕见，以及EspM和EspT对EPEC和EHEC感染有何影响。
Enterohaemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) translocate dozens of type III secretion system effectors, including the WxxxE effectors Map, EspM and EspT that activate Rho GTPases. While map, which is carried on the LEE pathogenicity island, is absolutely conserved among EPEC and EHEC strains, the prevalence of espM and espT is not known. Here we report the results of a large screen aimed at determining the prevalence of espM and espT among clinical EPEC and EHEC isolates. The results suggest that espM, detected in 51 % of the tested strains, is more commonly found in EPEC and EHEC serogroups that are linked to severe human infections. In contrast, espT was absent from all the EHEC isolates and was found in only 1.8 % of the tested EPEC strains. Further characterization of the virulence gene repertoire of the espT-positive strains led to the identification of a new ζ2 intimin variant. All the espT-positive strains but two contained the tccP gene. espT was first found in Citrobacter rodentium and later in silico in EPEC E110019, which is of particular interest as this strain was responsible for a particularly severe diarrhoeal outbreak in Finland in 1987 that affected 650 individuals in a school complex and an additional 137 associated household members. Comparing the protein sequences of EspT to that of E110019 showed a high level of conservation, with only three strains encoding EspT that differed in 6 amino acids. At present, it is not clear why espT is so rare, and what impact EspM and EspT have on EPEC and EHEC infection.
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作者：
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