Experimental infection of young chicks with attaching and effacing Escherichia coli

Young chicks were inoculated with six different strains of attaching and effacing Escherichia coli isolated from the feces of calves, pigs, chicks, and humans. Colibacilli of some serotypes had colonized the cecum of chicks by 7 days after inoculation. The characteristic lesions associated with bacterial attachment were also seen on the mucosal surface of the cecum. Electron microscopy revealed numerous colibacilli closely attached to the surface membrane of enterocytes. Cell membranes formed cups and pedestals at the base of the attached bacilli. The results of this study support the conclusion that young chicks can be used as a model for the study of the lesions caused by attaching and effacing E. coli strains. Recently, enteropathogenic Escherichia coli and enterohem-orrhagic E. coli have been isolated from several animals. Some of these bacteria attach closely to enterocytes and efface the microvilli of the cells and were named attaching and effacing E. coli (AEEC) (8). Numerous studies have confirmed that AEEC strains are capable of inducing attaching and effacing lesions in animals (2-4, 8, 12-14), in tissue culture models (5-7), and in humans infected with AEEC (10). Experimenta