Guinée P A, Jansen W H, Agterberg C M
Infect Immun. 1976 May;13(5):1369-77. doi: 10.1128/iai.13.5.1369-1377.1976.
The common antigen of calf enterotoxigenic strains of Escherichia coli, recently established as the K99 antigen, was studied by means of the slide agglutination test and immunoelectrophoresis. Specific antisera were obtained by absorption of crude antisera with ultrasonicates of autologous cells grown at 18C or by injection into rabbits of the purifies K99 antigen obtained by preparative electrophoresis. The K99 antigen was usually undetectable in calf enterotoxigenic E. coli cultures with capsular K antigens of the A variety grown at 37C on commercially available nutrient agar plates designed for the isolation of Enterobacteriaceae, but was rapidly detectable when grown on a buffered semi-synthetic medium at pH 7.5 (Minca medium). An alternative procedure for the isolation and identification of calf entertosigenic E. coli strains from feces, using the Minca medium, is proposed. K99 was found in 70 of 74 strains of E. coli, the enterotixigenicity of which was established in the ligated gut test in calves. None of the 20 cultures negative in the ligated gut test possessed K99 antigen. The K99 antigen is therefore probably a useful diagnostic tool for the identification of calf enterotixigenic E. coli strains, taking into account that K99 and enterotoxigenicity are controlled by different plasmids.
利用玻片凝集试验和免疫电泳法对最近确定为K99抗原的犊牛肠毒素性大肠杆菌菌株的共同抗原进行了研究。通过用在18℃培养的自体细胞超声裂解物吸收粗抗血清，或通过将制备电泳获得的纯化K99抗原注射到兔体内来获得特异性抗血清。在用于分离肠杆菌科细菌的市售营养琼脂平板上于37℃培养的具有A群荚膜K抗原的犊牛肠毒素性大肠杆菌培养物中，通常检测不到K99抗原，但在pH 7.5的缓冲半合成培养基（明卡培养基）上培养时可迅速检测到。本文提出了一种使用明卡培养基从粪便中分离和鉴定犊牛肠毒素性大肠杆菌菌株的替代方法。在74株大肠杆菌中，有70株检测到K99，这些菌株的肠毒素性已在犊牛结扎肠试验中得到证实。在结扎肠试验中呈阴性的20株培养物均未含有K99抗原。因此，考虑到K99和肠毒素性由不同质粒控制，K99抗原可能是鉴定犊牛肠毒素性大肠杆菌菌株的一种有用诊断工具。
