ABSTRACT
Enteroaggregative Escherichia coli (EAEC) is an increasingly recognized cause of diarrhea in children in developing and developed countries. EAEC is recognized by a characteristic aggregative pattern of adherence to human epithelial (HEp-2) cells cultured in vitro. This is the gold standard assay. The aggregative phenotype is associated with the presence of a 65 MDa plasmid (pAA) that also encodes several other putative virulence factors, such as the aggregative adherence fimbria I (AAF/I) and the enteroaggregative heat-stable enterotoxin (EAST1). The objective of this work was to evaluate the application of PCR (polymerase chain reaction) to identify EAEC strains in cases of acute diarrhea. A total of 87 E. coli strains, isolated from patients under 2 years of age with acute diarrhea in Mendoza, Argentina, were characterized by the reference method (HEp-2 assay), and by AAF/I- and EAST1-PCR. PCR sensitivity and specificity in comparison with the cell culture assay showed 94.4 sensitivity and 78.26 specificity. EAST1- and AAF/I-PCR could be recommended as a screening test, applicable to epidemiologic studies.