A Mini-Review of Enteroaggregative Escherichia coli with a Specific Target on the Virulence Factors Controlled by the AggR Master Regulator

Enteroaggregative Escherichia coli (EAEC) strains have been linked to several outbreaks of severe diarrhea around the world, and this bacterium is now commonly resistant to antibiotics. As part of the pathophysiology of EAEC, the characteristic pattern of adherence looks like stacked bricks on the intestinal epithelium. This phenotype depends on an aggregative adhesion plasmid (pAA), which codes for a regulatory protein named AggR. The AggR protein is a master regulator that transcriptionally actives the main virulence genes in this E. coli pathotype, such as those that encode the aggregative adhesion fimbriae, dispersin and its secretion apparatus, Aar regulatory protein, and type VI secretion system. Several reports have shown that AggR positively affects most EAEC virulence genes, functioning as a classic transcriptional activator in the promoter region of these genes, interacting with the RNA polymerase. This minireview article integrates the information about virulence determinants of EAEC controlled by the AggR regulator.