Frosch M, Roberts I, Görgen I, Metzger S, Boulnois G J, Bitter-Suermann D
Institute of Medical Microbiology, Johannes Gutenberg-University, Mainz, F.R.G.
Microb Pathog. 1987 May;2(5):319-26. doi: 10.1016/0882-4010(87)90074-x.
Among infectious diseases caused by E. coli the capsular type K1 plays a predominant role. E. coli K1 isolates account for 80% of cases of E. coli neonatal meningitis and 30% of E. coli sepsis strains. Serotyping of K1 strains has conventionally relied upon the use of K1-specific bacteriophages or serum agar methods with polyvalent anti K1 serum. In the study present here, 187 E. coli sepsis isolates have been analysed for production of the K1 antigen using K1 phages, K1 serum agar plates and Latex agglutination and ELISA using an IgG2a anti K1 monoclonal antibody. In total, 33 sepsis isolates (about 18%) were identified as K1 positive, with three of these strains proving negative in all tests except those exploiting the monoclonal antibody. That these three strains elaborate the K1 antigen was confirmed by Southern blot experiments using cloned K1 antigen production genes as probes. The failure of the three strains in all the tests except those that use monoclonal antibody could be explained by apparent disruption of K1 gene sequences that encode functions essential for the export of capsular material to the cell surface. The superiority of tests based on monoclonal antibodies above the conventional methods for detection of K1 antigen is evident.
在由大肠杆菌引起的传染病中，荚膜K1型起着主要作用。大肠杆菌K1分离株占大肠杆菌新生儿脑膜炎病例的80%，以及大肠杆菌败血症菌株的30%。传统上，K1菌株的血清分型依赖于使用K1特异性噬菌体或血清琼脂方法以及多价抗K1血清。在本研究中，使用K1噬菌体、K1血清琼脂平板以及使用IgG2a抗K1单克隆抗体的乳胶凝集试验和酶联免疫吸附测定，对187株大肠杆菌败血症分离株进行了K1抗原产生情况分析。总共33株败血症分离株（约18%）被鉴定为K1阳性，其中三株菌株除了使用单克隆抗体的检测外，在所有检测中均呈阴性。使用克隆的K1抗原产生基因作为探针进行的Southern印迹实验证实了这三株菌株确实产生K1抗原。这三株菌株在除使用单克隆抗体检测外的所有检测中均失败，这可以解释为编码将荚膜物质输出到细胞表面所必需功能的K1基因序列明显被破坏。基于单克隆抗体的检测方法在检测K1抗原方面优于传统方法，这一点显而易见。
