肠杆菌科是由一大类互相有关的,有动力或无动力的革兰氏阴性无芽胞细菌所组成。这些细菌,可分为若干个菌族和菌属。菌族和菌属之间,存在着极其错综复杂的关系。菌族和菌属的分类是按其是否具有共同的生化特性和抗原的亲缘关系为依据。由于大肠艾希氏菌属与志贺氏菌属之间的关系不论在生化和血清学方面均较其它菌属更为密切,故将其列入同一菌族。同样,沙门氏菌属和枸椽酸杆菌属之间也存在着与上述相似之处,因此,被列为另一菌族内的不同菌属。志贺氏菌属的 O 抗原与大肠艾希氏菌或 Enterobacteriaceae is composed of a large group of related, motivated or unpowered Gram-negative, non-spore-forming bacteria. These bacteria can be divided into a number of bacteria and genus. Between the genus and the genus, there is an extremely intricate relationship. The genus and genus are classified according to whether they share common biochemical characteristics and the genetic relationship of the antigens. As the relationship between Escherichia coli and Shigella is more biochemical and serological than other genus, it is included in the same genus. Similarly, Salmonella and Citrobacter also exist between the above similarities, therefore, is classified as a different genus within the different genus. Shigella O antigen and Escherichia coli or