Resumo

RUTTLER, M.E. et al. Evaluation of a multiplex PCR method to detect enteroaggregative Escherichia coli. Biocell [online]. 2006, vol.30, n.2, pp.301-308. ISSN 0327-9545.

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 aggRastA 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.

Palavras-chave : Diarrhea; Escherichia coli; Cell culture; PCR (Polymerase Chain Reaction).

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