Mills K W, Tietze K L
J Clin Microbiol. 1984 Apr;19(4):498-501. doi: 10.1128/jcm.19.4.498-501.1984.
For Escherichia coli to produce diarrhea in animals it must possess the ability to attach to the epithelial cells of the intestine and to produce enterotoxins. Tests developed to differentiate pathogenic from nonpathogenic E. coli have relied on detection of adherence structures called pili or detection of the toxins. We utilized a monoclonal antibody to K99 pili in an enzyme-linked immunosorbent assay to detect the presence of K99 pili in E. coli isolated from calves. Twenty-three E. coli isolates that were known to be stable toxin positive were all shown to produce K99 pili. A 100% correlation also was shown between the presence of K99 antigen and production of stable toxin by E. coli isolates. Of the 251 isolates, 245 were negative by K99 enzyme-linked immunosorbent assay and stable toxin assay. The other six were positive on both tests. The enzyme-linked immunosorbent assay also was shown to be specific for K99 pili by antibody-blocking assays. The number of E. coli necessary for detecting K99 pili by enzyme-linked immunosorbent assay was determined to be 3.5 X 10(5) bacteria per ml.
大肠杆菌要在动物体内引发腹泻，就必须具备附着于肠道上皮细胞并产生肠毒素的能力。为区分致病性大肠杆菌和非致病性大肠杆菌而开发的检测方法，一直依赖于对称为菌毛的黏附结构的检测或对毒素的检测。我们在酶联免疫吸附测定中使用针对K99菌毛的单克隆抗体，来检测从犊牛分离出的大肠杆菌中K99菌毛的存在。已知为稳定毒素阳性的23株大肠杆菌分离株均显示产生K99菌毛。K99抗原的存在与大肠杆菌分离株产生稳定毒素之间也呈现出100%的相关性。在251株分离株中，245株通过K99酶联免疫吸附测定和稳定毒素测定呈阴性。另外6株在两项检测中均呈阳性。通过抗体阻断试验表明，酶联免疫吸附测定对K99菌毛也具有特异性。经测定，通过酶联免疫吸附测定检测K99菌毛所需的大肠杆菌数量为每毫升3.5×10⁵个细菌。
