The molecular characterisation of Escherichia coli K1 isolated from neonatal nasogastric feeding tubes.
The molecular characterisation of Escherichia coli K1 isolated from neonatal nasogastric feeding tubes.
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DOI：
10.1186/s12879-015-1210-7
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发表时间：
2015-10-26
影响因子：
3.7
通讯作者：
Forsythe S
中科院分区：
文献类型：
--
作者：
Alkeskas A;Ogrodzki P;Saad M;Masood N;Rhoma NR;Moore K;Farbos A;Paszkiewicz K;Forsythe S
革兰氏阴性细菌性新生儿脑膜炎最常见的病因是大肠杆菌K1。它的死亡率为10 - 15%，在30 - 50%的病例中有神经系统后遗症。感染可归因于医院源，但肠内喂食管的预定植并未被认为是一个特定的危险因素。采用脉冲场凝胶电泳技术对从新生儿鼻胃进食管残余管腔液和生物膜中分离到的30株大肠杆菌进行基因分型，并进行7位点多位点序列分型。利用特异性PCR探针、基因组分析和体外组织培养试验确定潜在致病性和生物膜相关性状。大肠杆菌聚类为5个脉冲型，分别为序列型（ST） 95、73、127、394和2076 （Achman方案）。在2周的时间内，从11例不同喂养方式的新生儿中分离出肠外致病性大肠杆菌（ExPEC）系统发育组B2 ST95血清型O1:K1:NM菌株。大肠杆菌K1 ST95菌株编码与新生儿脑膜炎和细胞外基质形成相关的各种毒力性状。这些菌株在U937巨噬细胞中附着和侵袭肠道、人和大鼠脑细胞，并持续48小时。大肠杆菌STs 73、394和2076也存在于巨噬细胞中，并侵袭Caco-2和人脑细胞，但只有ST394侵袭大鼠脑细胞。值得注意的是，大肠杆菌ST127没有侵袭任何细胞系。大肠杆菌K1在新生儿重症监护病房内的传播途径尚不确定，然而，新生儿肠内喂养管的定植可能是一个水库来源，可能在摄入后对新生儿构成严重的健康风险。本文的在线版本（doi:10.1186/s12879-015-1210-7）包含补充材料，授权用户可以使用。
The most common cause of Gram-negative bacterial neonatal meningitis is E. coli K1. It has a mortality rate of 10–15 %, and neurological sequelae in 30–50 % of cases. Infections can be attributable to nosocomial sources, however the pre-colonisation of enteral feeding tubes has not been considered as a specific risk factor. Thirty E. coli strains, which had been isolated in an earlier study, from the residual lumen liquid and biofilms of neonatal nasogastric feeding tubes were genotyped using pulsed-field gel electrophoresis, and 7-loci multilocus sequence typing. Potential pathogenicity and biofilm associated traits were determined using specific PCR probes, genome analysis, and in vitro tissue culture assays. The E. coli strains clustered into five pulsotypes, which were genotyped as sequence types (ST) 95, 73, 127, 394 and 2076 (Achman scheme). The extra-intestinal pathogenic E. coli (ExPEC) phylogenetic group B2 ST95 serotype O1:K1:NM strains had been isolated over a 2 week period from 11 neonates who were on different feeding regimes. The E. coli K1 ST95 strains encoded for various virulence traits associated with neonatal meningitis and extracellular matrix formation. These strains attached and invaded intestinal, and both human and rat brain cell lines, and persisted for 48 h in U937 macrophages. E. coli STs 73, 394 and 2076 also persisted in macrophages and invaded Caco-2 and human brain cells, but only ST394 invaded rat brain cells. E. coli ST127 was notable as it did not invade any cell lines. Routes by which E. coli K1 can be disseminated within a neonatal intensive care unit are uncertain, however the colonisation of neonatal enteral feeding tubes may be one reservoir source which could constitute a serious health risk to neonates following ingestion. The online version of this article (doi:10.1186/s12879-015-1210-7) contains supplementary material, which is available to authorized users.