Shimizu M, Sakano T, Yamamoto J, Kitajima K
Bacteriology and Parasitology Section, Zen-noh Institute of Animal Health, Sakura, Chiba.
Microbiol Immunol. 1987;31(5):417-26. doi: 10.1111/j.1348-0421.1987.tb03104.x.
Escherichia coli isolates from calves with diarrhea (1 day to 8 weeks old, 140 individuals) were surveyed for the three immunologically distinct fimbrial adhesins FY, 31A, and K99. Of a total of 1,370 strains isolated, 96 (7.0%), 34 (2.5%), 75 (5.5%), and 13 (0.9%) were identified as FY+, 31A+, FY+.31A+, and K99+, respectively. The K99+ strains also manifested heat-stable enterotoxin production (ST+), while FY+, 31A+, and FY+.31A+ strains were ST-. Expression of FY and 31A was repressed at lower temperatures or poor aeration. The FY+ and 31A+ E. coli showed mannose-resistant hemagglutinating activity with bovine erythrocytes. Electron microscopy revealed that FY is a gently curled fimbria with a mean diameter of 4.2 nm, and 31A is a fimbria with a mean diameter of 5.1 nm. The molecular mass of protein subunits was found to be approximately 20 kilodaltons (Kd) and 19 Kd for FY and 31A, respectively. Lethal diarrhea of neonatal calves was induced by challenge with the combination of a K99+.ST+ E. coli strain and either a 31A+ E. coli strain or a 31A+ E. coli strain plus an FY+ E. coli strain under the experimental conditions in which lethal diarrhea was not induced by challenge with a K99+.ST+ E. coli strain alone.
对140头腹泻犊牛（1日龄至8周龄）分离出的大肠杆菌进行了三种免疫特性不同的菌毛黏附素FY、31A和K99的检测。在总共分离出的1370株菌株中，分别有96株（7.0%）、34株（2.5%）、75株（5.5%）和13株（0.9%）被鉴定为FY+、31A+、FY+.31A+和K99+。K99+菌株还表现出热稳定肠毒素产生（ST+），而FY+、31A+和FY+.31A+菌株为ST-。在较低温度或通气不良的情况下，FY和31A的表达受到抑制。FY+和31A+大肠杆菌对牛红细胞表现出甘露糖抗性血凝活性。电子显微镜显示，FY是一种平均直径为4.2纳米的轻度卷曲菌毛，31A是一种平均直径为5.1纳米的菌毛。发现FY和31A的蛋白质亚基分子量分别约为20千道尔顿（Kd）和19 Kd。在单独用K99+.ST+大肠杆菌菌株攻毒不会诱发致死性腹泻的实验条件下，用K99+.ST+大肠杆菌菌株与31A+大肠杆菌菌株或31A+大肠杆菌菌株加FY+大肠杆菌菌株联合攻毒诱发了新生犊牛的致死性腹泻。
