title: Evaluation of a multiplex PCR method to detect enteroaggregative Escherichia coli.
abstract: Enteroaggregative Escherichia coli (EAEC) has been implicated in sporadic diarrhea in children and adults and has been identified as the cause of several outbreaks worldwide. The HEp-2 test remains the gold standard for identification of this pathotype. A 60-65 MDa plasmid encodes the aggregative adherence fimbriae (AAF/I and AAF/II), a transcriptional activator (aggR gene), the enteroaggregative heat-stable enterotoxin EAST1 (astA gene) and a cytotoxin (Pet). The standard assay for EAEC is performed only in research laboratories, because it is expensive, labor intensive and time-consuming. The Polymerase Chain Reaction (PCR) offers the possibility of rapid diagnosis. In the current study, a multiplex PCR assay which checks aggR and astA genes was designed. Eigthy-eight E. coli strains, isolated from children with acute diarrhea in Mendoza, Argentina, were characterized by the reference method (HEp-2 assay), and by aggR-astA PCR. A strong correlation between the presence of the specific marker aggR and the reference test was found. The astA gene had a similar distribution between aggregative and localized strains, indicating that this gene could not be considered as a marker of EAEC. We conclude that aggR may be used to identify EAEC, using the PCR method as a screening test.
authors.affiliation: Area de Química Biológica, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina. mruttler@fcm.uncu.edu.ar
authors.forename: M E
authors.initials: ME
authors.lastname: Rüttler
authors.forename: C S
authors.initials: CS
authors.lastname: Yanzón
authors.forename: M J
authors.initials: MJ
authors.lastname: Cuitiño
authors.forename: N F
authors.initials: NF
authors.lastname: Renna
authors.forename: M A
authors.initials: MA
authors.lastname: Pizarro
authors.forename: A M
authors.initials: AM
authors.lastname: Ortiz
mesh_terms: D001422:Bacterial Adhesion / Q000502:physiology; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D004587:Electrophoresis, Agar Gel; D004926:Escherichia coli / Q000166:cytology / Q000235:genetics* / Q000302:isolation & purification*; D029968:Escherichia coli Proteins / Q000235:genetics; D006801:Humans; D007223:Infant; D016133:Polymerase Chain Reaction / Q000379:methods*; D012703:Serotyping; D015534:Trans-Activators / Q000235:genetics
chemical_list: C088603:AggR protein, E coli; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D015534:Trans-Activators