enteroaggregative

Enteroaggregative refers to a diarrheagenic pathotype of Escherichia coli, known as enteroaggregative E. coli (EAEC). EAEC is defined by its characteristic pattern of colonization in the intestine, described as a stacked-brick adherence to mucosal cells and by its ability to form biofilms. The adherence is mediated by a family of fimbriae (aggregative adherence fimbriae, AAF) and other virulence determinants carried on the pAA plasmid, including aggR, the transcriptional regulator that coordinates virulence gene expression. Additional factors associated with EAEC include dispersin (aap), the dispersin transporter (aatA), and various toxins such as the enteroaggregative heat-stable toxin (astA). EAEC can be identified by molecular markers (for example aggR, aaiC, aatA) or by laboratory observation of the characteristic adherence pattern in cell culture assays, alongside routine culture of stool samples.

Pathogenesis involves adherence and biofilm formation on the intestinal mucosa, leading to sustained inflammation, secretory diarrhea, and malabsorption in some cases. EAEC is a common cause of both acute traveler's diarrhea and persistent diarrhea in children, particularly in low- and middle-income countries, though it can be detected in sporadic cases worldwide. Clinical presentation ranges from mild, self-limited watery diarrhea to prolonged symptoms with mucus and abdominal cramping; fever is less common.

Diagnosis typically relies on stool testing with molecular assays for EAEC-associated genes or, in research settings, HEp-2 adherence assays. Treatment is mainly supportive, emphasizing oral rehydration and electrolyte management; antibiotics may be used in severe cases or persistent illness, but resistance patterns vary and require local guidance. Prevention focuses on standard hygiene and safe food and water practices.