Pathogen
Five disinict pathotypes
- Enterotoxigenic E. coli (ETEC)
- Enteropathogenic E. coli (EPEC)
- Enteroinvasive E. coli (EIEC)
- Enteroaggregative E. coli (EAEC)
- Enterohemorrhagic Escherichia coli (STEC)
Enterotoxigenic E. coli (ETEC)
- ETEC survives readily in water and food and is one of the most common bacterial causes of dehydrating diarrheal illness in children under two years of age in resource-limited regions. ETEC can also cause diarrhea among travelers to tropical regions and is emerging as a pathogen in resource-rich settings. ETEC causes primarily watery diarrhea through plasmid-encoded toxin production.
Enteropathogenic E. coli (EPEC)
- EPEC has been associated with sporadic diarrheal illness and diarrhea outbreaks, most commonly among children under six months of age in resource-limited countries. EPEC strains are defined by their characteristic “attaching and effacing” effect upon interaction with epithelial cells and by the fact that they do not produce Shiga toxin. EPEC proteins affect cell physiology through adherence and induction of signal transduction.
Enteroinvasive E. coli (EIEC)
- EIEC infection appears to be uncommon. Clinical disease begins as watery diarrhea that may progress to bloody diarrhea and dysentery. EIEC is closely related to Shigella, and the same genes facilitate pathogenesis of both organisms. EIEC invades the intestinal cell, multiplies intracellularly, and extends into the adjacent intestinal cells.
Enteroaggregative E. coli (EAEC)
- EAEC is associated with persistent and acute diarrheal illness among many demographic groups in both resource-limited and -rich settings and may be associated with linear growth retardation. On tissue culture adherence assays, EAEC has a distinctive palisading adherence on human epithelial type 2 (HEp-2) cells. The pathogenesis of diarrhea caused by EAEC is incompletely elucidated.
Treatment
- Supportive
- For patients with diarrhea who have a pathogenic E. coli identified on stool testing, we suggest not routinely administering antibiotic therapy.
- Antibiotic therapy (eg, with azithromycin or ciprofloxacin) is reasonable in patients with severe, bloody, or persistent diarrhea, particularly in children or immunocompromised hosts.