Genetics of Virulence in Enteroinvasive Escherichia coli

摘要

The term enteroinvasive Escherichia coli (EIEC) is used to differentiate a small number of E. coli bioserotypes which can invade the intestinal mucosa and cause a dysenterylike syndrome similar to shigellosis. As shown in Table 1, the EIEC biotype is usually lysine decarboxylase negative (see reference 10 for exception), usually nonmotile, and frequently lactose negative. In these respects EIEC are physiologically similar to shigellae. Table 2 lists the 0-antigen serogroups which include EIEC strains and shows that a majority of these express somatic antigens which are strongly related or identical to Shigella O antigens. EIEC strains are also positive in various laboratory models designed to evaluate enteroinvasive potential. For example, they can invade HeLa cells and evoke keratoconjunctivitis in the guinea pig eye (Sereny test). Another attribute of virulence in shigellae is the Shiga toxin. An EIEC strain which belongs to the 0143 serogroup has been shown to produce as much Shiga toxin as a strain of Shigella flexneri 2a.