Characterization of an enterotoxigenic Escherichia coli strain from Africa expressing a putative colonization factor.
Characterization of an enterotoxigenic Escherichia coli strain from Africa expressing a putative colonization factor.
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来自非洲的表达推定定植因子的产肠毒素大肠杆菌菌株的表征。
DOI：
10.1128/iai.67.8.4019-4026.1999
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发表时间：
1999
影响因子：
3.1
通讯作者：
PeruskiJr,LF
中科院分区：
文献类型：
--
作者：
Khalil,SB;Cassels,FJ;Shaheen,HI;Pannell,LK;El-Ghorab,N;Kamal,K;Mansour,M;Savarino,SJ;PeruskiJr,LF
从埃及一名腹泻儿童中分离出一株血清型为O 114：H−的产肠毒素性大肠杆菌（ETEC）菌株，该菌株同时表达不耐热肠毒素和耐热肠毒素，且定植因子（CF）检测结果为阴性。该菌株WS 0115 A诱导牛红细胞血凝并粘附于肠细胞样细胞系Caco-2，这表明它可能产生新型菌毛。经硫酸铵差示沉淀和柱层析纯化的表面表达抗原经十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（16%聚丙烯酰胺）分离时，得到Mr为14，800的单一蛋白带。产生针对该推定菌毛抗原的单克隆抗体，并在斑点印迹试验中与菌株WS 0115 A以及CS 1-、CS 17-和CS 19-阳性菌株反应。反应性是温度依赖性的，细胞在37°C生长时显示反应性，但在22°C生长时不显示反应性。免疫印迹分析表明，从菌株WS 0115 A菌毛制备的单克隆抗体反应与一个单一的蛋白带。电镜和免疫电镜观察发现菌株WS 0115 A表面有菌毛样结构。这些结构是刚性的，直径为6.8至7.4 nm。电喷雾质谱分析表明，纯化的菌毛的质量为14，965 Da。菌毛的N-末端序列确定它是CFA/I家族的成员，与最近在印度鉴定的新CF CS 19的氨基末端序列相同。累积起来，我们的结果表明，这菌毛是CS 19。对从埃及腹泻儿童中分离的ETEC菌株进行筛选，发现最初报告为CF阴性的菌株中有4.2%对此CF呈阳性，表明其与ETEC的发病机制具有生物学相关性。
An enterotoxigenicEscherichia coli(ETEC) strain of serotype O114:H− that expressed both heat-labile and heat-stable enterotoxins and tested negative for colonization factors (CF) was isolated from a child with diarrhea in Egypt. This strain, WS0115A, induced hemagglutination of bovine erythrocytes and adhered to the enterocyte-like cell line Caco-2, suggesting that it may elaborate novel fimbriae. Surface-expressed antigen purified by differential ammonium sulfate precipitation and column chromatography yielded a single protein band withMr14,800 when resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (16% polyacrylamide). A monoclonal antibody against this putative fimbrial antigen was generated and reacted with strain WS0115A and also with CS1-, CS17-, and CS19-positive strains in a dot blot assay. Reactivity was temperature dependent, with cells displaying reactivity when grown at 37°C but not when grown at 22°C. Immunoblot analysis of a fimbrial preparation from strain WS0115A showed that the monoclonal antibody reacted with a single protein band. Electron microscopy and immunoelectron microscopy revealed fimbria-like structures on the surface of strain WS0115A. These structures were rigid and measured 6.8 to 7.4 nm in diameter. Electrospray mass-spectrometric analysis showed that the mass of the purified fimbria was 14,965 Da. The N-terminal sequence of the fimbria established that it was a member of the CFA/I family, with sequence identity to the amino terminus of CS19, a new CF recently identified in India. Cumulatively, our results suggest that this fimbria is CS19. Screening of a collection of ETEC strains isolated from children with diarrhea in Egypt found that 4.2% of strains originally reported as CF negative were positive for this CF, suggesting that it is biologically relevant in the pathogenesis of ETEC.