Ahrén C M, Gothefors L, Stoll B J, Salek M A, Svennerholm A M
J Clin Microbiol. 1986 Mar;23(3):586-91. doi: 10.1128/jcm.23.3.586-591.1986.
Fecal Escherichia coli isolates from 196 patients with watery diarrhea and 68 healthy individuals (controls) were analyzed in Bangladesh immediately after isolation for the presence of colonization factor antigen (CFA) I or II (CFA/I or CFA/II, respectively) by a mannose-resistant hemagglutination (MRHA) test with six species of erythrocytes and by a slide agglutination test with absorbed CFA/I or CFA/II antisera. The presence of CFAs was confirmed by immunodiffusion analyses done in Sweden. By these methods, it was found that 49 of 69 enterotoxin-producing E. coli strains isolated from patients carried CFA/I or CFA/II, whereas none of the nonenterotoxigenic E. coli isolates or the three toxin-positive strains isolated from healthy individuals carried these adhesins. All E. coli strains retained their MRHA ability after transportation to Sweden followed by one subculture and after storage at -70 degrees C (but not at room temperature) for 1 to 2 years without further subculturing. After 5 to 10 subcultures of the fresh isolates, however, 70% of the initially CFA/I- and 80% of the initially CFA/II-carrying strains analyzed did not hemagglutinate. The efficacy of different methods for detecting CFAs on the fresh isolates was compared with that of immunodiffusion. The sensitivity of MRHA with human blood group A erythrocytes for the detection of CFA/I was high (97%), but the specificity was only 69%. The sensitivity of MRHA with bovine erythrocytes for the detection of CFA/II in Bangladesh was very low but increased considerably when chicken erythrocytes were also used. Whereas both false-positive and false-negative reactions were obtained when absorbed CFA antisera were used for agglutination, antisera against purified CFAs were equally effective as immunodiffusion in identifying CFA/I and CFA/II-carrying strains.
在孟加拉国，对从196例水样腹泻患者和68名健康个体（对照）中分离出的粪便大肠杆菌菌株，在分离后立即进行分析，通过用六种红细胞进行的甘露糖抗性血凝试验（MRHA）以及用吸收的CFA/I或CFA/II抗血清进行的玻片凝集试验，检测是否存在定植因子抗原（CFA）I或II（分别为CFA/I或CFA/II）。通过在瑞典进行的免疫扩散分析确认了CFA的存在。通过这些方法发现，从患者中分离出的69株产肠毒素大肠杆菌菌株中有49株携带CFA/I或CFA/II，而从健康个体中分离出的非产肠毒素大肠杆菌菌株或三株毒素阳性菌株均未携带这些黏附素。所有大肠杆菌菌株在转运至瑞典继代培养一次后以及在-70℃（而非室温）保存1至2年且未进一步传代培养后，仍保留其MRHA能力。然而，新鲜分离株传代培养5至10次后，最初携带CFA/I的菌株中有70%以及最初携带CFA/II的菌株中有80%不再发生血凝。将检测新鲜分离株中CFA的不同方法的效能与免疫扩散法进行了比较。用人A型血红细胞进行的MRHA检测CFA/I的敏感性较高（97%），但特异性仅为69%。在孟加拉国，用牛红细胞进行的MRHA检测CFA/II的敏感性非常低，但同时使用鸡红细胞时敏感性显著提高。当使用吸收的CFA抗血清进行凝集时会出现假阳性和假阴性反应，而针对纯化CFA的抗血清在鉴定携带CFA/I和CFA/II的菌株方面与免疫扩散法同样有效。
