Cloning of the RDEC-1 locus of enterocyte effacement (LEE) and functional analysis of the phenotype on HEp-2 cells.

EPEC Escherichia coli are an important cause of epidemic diarrhea in infants. The disease is characterized by attaching and effacing (A/E) lesions where the bacteria attach intimately to the enterocyte surface resulting in localized destruction of microvilli. A 35-kb chromosomal locus termed LEE (locus of enterocyte effacement) in an EPEC strain (E2348/69) has recently been found and is thought to contain all the necessary genes for A/E lesions. RDEC-1 is a strain of E. coli that causes diarrhea in rabbits by a similar mechanism and serves as a model for human EPEC disease. We report 1) the cloning of the RDEC-1 LEE, 2) show that the RDEC-1 LEE is similar in size to the LEE in E2348/69, 3) the RDEC-1 LEE possesses all four regions of the E2348/69 LEE, 4) there are restriction site polymorphisms between the RDEC-1 LEE and that of E2348/69, and 5) the RDEC-1 LEE clone is functionally similar to E2348/69 in its fluorescent actin staining test and suggests that the LEE may be sufficient for the production of A/E lesions by these strains.