Atypical enteropathogenetic Escherichia coli (atypical EPEC)

Abstract

The term atypical EPEC is used to define the EPEC strains that does not have the EAF plasmid. This EPEC category has been found in association with diarrhea in several countries, including Brazil. At present they are the most common bacterial agent in child endemic diarrhea in Brazil. Atypical EPEC strains may belong to serotypes of the classical EPEC. The serogroups (classical serotypes) or to serotypes in other the serogroups (non classical serotypes). The classical atypical EPEC serotypes have been identified in several studies but the non-classical ones are less known. The classical serotypes are genetically related to E. coli O157:H7 and like this serotype have been isolated from bovines and other animal species. The most common virulence factors identified so far in atypical EPEC strains are the toxins EAST and Hly but recent studies suggest that there are many others factors. The objectives of this project may be divided in two groups: one group is aimed at determining the virulence mechanisms of these organisms and includes studies on their toxins, adhesins, genetic of these virulence factors, interaction mechanisms with the host cell, cell response and proteomics. The other group of objectives includes the characterization of the serotypes and clonal groups of atypical EPEC, genetic relationships of the human and animal strains an development of animal models. More details about these objectives may be found in the text of the project. (AU)