Enteropathogenic Escherichia coli: a versatile diarrheagenic category

Abstract

Escherichia coli (EPEC) was the first category of E. coli to be discovered and continues to be associated with sporadic cases and outbreaks of diarrhea in children. In 1995 it was classified as typical and atypical EPEC and, until the current moment, much has been studied about the differences of these two pathogenic and epidemiological subcategories and their similarity to other pathotypes. To better know these studies and consolidate this information, this literature evaluated 98 bibliographic sources, with 81 articles, eight theses, four dissertations and five books. This research highlighted the following findings and conclusions: the atypical EPEC (a-EPEC) are present in humans and a variety of animal hosts, suggesting that they may serve as a reservoir and source of infection for humans and the environment; typical EPEC (t-EPEC) has humans as the main reservoir, however, they have been recorded in some rare occurrences wildlife; a-EPEC have several common virulence factors and specific categories of other pathogens, suggesting that increased prevalence of EPEC is related to interconversion, the presence of the LEE (locus of enteracyte effacement) complete region (LEEA-D) and pathogenicity island HI-122 (efa1/lifA, nleB, nleE, set/ent) with the hemolysin gene (ehxA) and the toxin (paa) can help in identification of potentially pathogenic a-EPEC, but the conclusive identification of EPEC is performed by molecular diagnosis, which identifies genes eae, EAF and stx, and the profile eae+EAF+stx− of t-EPEC and eae+EAF−stx− in a-EPEC.