Imberechts H, De Greve H, Schlicker C, Bouchet H, Pohl P, Charlier G, Bertschinger H, Wild P, Vandekerckhove J, Van Damme J
Laboratory of Bacteriology, National Institute for Veterinary Research, Brussels, Belgium.
Infect Immun. 1992 May;60(5):1963-71. doi: 10.1128/iai.60.5.1963-1971.1992.
F107 fimbriae were isolated and purified from edema disease strain 107/86 of Escherichia coli. Plasmid pIH120 was constructed, which contains the gene cluster that codes for adhesive F107 fimbriae. The major fimbrial subunit gene, fedA, was sequenced. An open reading frame that codes for a protein with 170 amino acids, including a 21-amino-acid signal peptide, was found. The protein without the signal sequence has a calculated molecular mass of 15,099 Da. Construction of a nonsense mutation in the open reading frame of fedA abolished both fimbrial expression and the capacity to adhere to isolated porcine intestinal villi. In a screening of 28 reference edema disease strains and isolates from clinically ill piglets, fedA was detected in 24 cases (85.7%). In 20 (83.3%) of these 24 strains, fedA was found in association with Shiga-like toxin II variant genes, coding for the toxin that is characteristic for edema disease strains of E. coli. The fimbrial subunit gene was not detected in enterotoxigenic E. coli strains. Because of the capacity of E. coli HB101(pIH120) transformants to adhere to isolated porcine intestinal villi, the high prevalence of fedA in edema disease strains, and the high correlation with the Shiga-like toxin II variant toxin-encoding genes, we suggest that F107 fimbriae are an important virulence factor in edema disease strains of E. coli.
从大肠杆菌水肿病107/86菌株中分离并纯化出F107菌毛。构建了质粒pIH120，其包含编码黏附性F107菌毛的基因簇。对主要菌毛亚基基因fedA进行了测序。发现了一个开放阅读框，其编码一种含170个氨基酸的蛋白质，包括一个21个氨基酸的信号肽。去除信号序列后的蛋白质计算分子量为15,099道尔顿。在fedA的开放阅读框中构建无义突变消除了菌毛表达以及黏附分离的猪肠绒毛的能力。在对28株参考水肿病菌株和临床患病仔猪分离株的筛选中，24例（85.7%）检测到fedA。在这24株菌株中的20株（83.3%）中，发现fedA与志贺样毒素II变体基因相关，该基因编码大肠杆菌水肿病菌株特有的毒素。在产肠毒素大肠杆菌菌株中未检测到菌毛亚基基因。由于大肠杆菌HB101(pIH120)转化子具有黏附分离的猪肠绒毛的能力、fedA在水肿病菌株中的高流行率以及与志贺样毒素II变体毒素编码基因的高度相关性，我们认为F107菌毛是大肠杆菌水肿病菌株中的一种重要毒力因子。
