EPEC

Enteropathogenic Escherichia coli (EPEC) is a pathotype of Escherichia coli that causes diarrhea, particularly in young children in developing countries. EPEC adheres to the intestinal mucosa and forms attaching and effacing lesions, leading to watery diarrhea and dehydration. The pathogenic mechanism centers on the locus of enterocyte effacement (LEE), which encodes a type III secretion system that injects effector proteins such as Tir into enterocytes and relies on the bacterial adhesin intimin (encoded by eae) to promote intimate attachment and pedestal formation. Typical EPEC (tEPEC) carries both the EAF plasmid, encoding bundle-forming pili (BFP), and LEE; atypical EPEC (aEPEC) lacks EAF and BFP but retains LEE.

Transmission is primarily fecal-oral, via contaminated water or food. Infants and young children are most affected, with outbreaks occurring in daycare centers and among travelers. Symptoms are usually watery diarrhea and abdominal cramps, with variable fever and vomiting; dehydration may be severe in infants.

Diagnosis involves stool testing for virulence determinants (such as eae, with or without bfpA) alongside standard culture, with molecular methods used to confirm the presence of EPEC-associated genes. Histology, when available, can show attaching and effacing lesions.

Treatment is mainly supportive, focusing on oral or, if necessary, intravenous rehydration and zinc supplementation; antibiotics are not routinely recommended and may be used in severe cases or outbreaks based on clinical judgment and susceptibility data. Prevention relies on improved sanitation, safe drinking water, hand hygiene, and breastfeeding. There is no widely available vaccine for EPEC.