Escherichia coli K1 aslA contributes to invasion of brain microvascular endothelial cells in vitro and in vivo
Escherichia coli K1 aslA contributes to invasion of brain microvascular endothelial cells in vitro and in vivo
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DOI：
10.1128/iai.68.9.5062-5067.2000
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发表时间：
2000-09-01
影响因子：
3.1
通讯作者：
Kim, KS
中科院分区：
文献类型：
--
作者：
Hoffman, JA;Badger, JL;Kim, KS
新生儿大肠杆菌脑膜炎仍然是一种毁灭性的疾病，尽管在支持性护理措施和杀菌抗生素方面取得了进展，但其发病率和死亡率仍然高得令人无法接受。为了进一步提高我们的能力，以改善受影响的新生儿的结果，更好地了解疾病的发病机制是必要的。为了鉴定与大肠杆菌相关的潜在细菌基因。大肠杆菌侵入血脑屏障，脑脊液分离的大肠杆菌。用TnphoA诱变大肠杆菌K1。发现TnphoA突变体27 A-6与野生型相比具有显著降低的侵袭脑微血管内皮细胞的能力。在体内，32%感染突变体27 A-6的动物发生脑膜炎，而感染亲本菌株的动物则为82%，尽管菌血症水平相似。对27 A-6中TnphoA插入片段侧翼的DNA进行克隆和测序，并确定其与E. coliK-12 aslA（arylsulfatase-like基因）。对E. coliK 1aslA基因产物显示与在真核生物以及原核生物中发现的充分表征的芳基硫酸酯酶家族的同源性。通过靶向基因破坏和内部基因缺失构建了另外两个aslA突变体。这两种突变体都表现出降低的侵袭表型，类似于TnphoA突变体27 A-6。当aslA以反式供应时，这些突变体的侵袭减少表型得到互补。这是首次证明该位点有助于E. coli K1.
Neonatal Escherichia coli meningitis remains a devastating disease, with unacceptably high morbidity and mortality despite advances in supportive care measures and bactericidal antibiotics. To further our ability to improve the outcome of affected neonates, a better understanding of the pathogenesis of the disease is necessary. To identify potential bacterial genes which contribute to E. coli invasion of the blood-brain barrier, a cerebrospinal fluid isolate of E. coli K1 was mutagenized with TnphoA. TnphoA mutant 27A-6 was found to have a significantly decreased ability to invade brain microvascular endothelial cells compared to the wild type. In vivo, 32% of the animals infected with mutant 27A-6 developed meningitis, compared to 82% of those infected with the parent strain, despite similar levels of bacteremia. The DNA flanking the TnphoA insertion in 27A-6 was cloned and sequenced and determined to be homologous to E. coli K-12 aslA (arylsulfatase-like gene). The deduced amino acid sequence of the E. coli K1 aslA gene product shows homology to a well-characterized arylsulfatase family of enzymes found in eukaryotes, as well as prokaryotes. Two additional aslA mutants were constructed by targeted gene disruption and internal gene deletion. Both of these mutants demonstrated decreased invasion phenotypes, similar to that of TnphoA mutant 27A-6. Complementation of the decreased-invasion phenotypes of these mutants was achieved when aslA was supplied in trans. This is the first demonstration that this locus contributes to invasion of the blood-brain barrier by E. coli K1.