OBJECTIVE: To examine the interactions of Enteroaggregative Escherichia coli strains with small and large intestinal mucosa, in order to detect potential alterations in both regions of the digestive tract. METHODS: Enteroaggregative Escherichia coli strains, isolated from stools of infants with persistent diarrhea and the prototype strain 042 (O44:H18), isolated from a child with diarrhea in Lima, Peru (positive control), were analised by light microscopy after in vitro organ culture assay of ileal and colonic mucosa. The interactions between the different enteroaggregative Escherichia coli strains and the ileal and colonic mucosa were analysed. RESULTS: Light microscopy analysis suggested an association of enteroaggregative Escherichia coli strains with the epithelium, inducing alterations. These bacteria adhered to both small and large bowel mucosa. The enteroaggregative Escherichia coli strains induced alterations in those areas where they were directly interacting with the epithelium. In the ileum, some areas showed a secondary internalization. CONCLUSIONS: The enteroaggregative Escherichia coli strains could cause persistent diarrhea inducing alterations in the small intestinal structures, where the digestive-absorptive functions take place. Inflammatory lesions observed in colons could justify the colitis described in some children infected by enteroaggregative Escherichia coli.
enteroaggregative Escherichia coli; persistent diarrhea; microscopy
