A multiplex PCR for identifying Shiga-like toxin-producing Escherichia coli O157:H7.

A multiplex PCR assay specifically detecting Escherichia coli O157:H7 was developed by employing primers amplifying a DNA sequence upstream of E. coli O157:H7 eaeA gene and genes encoding Shiga-like toxins (SLT) I and II. Analysis of 151 bacterial strains revealed that all E. coli O157:H7 strains were identified simultaneously with the SLT types and could be distinguished from E. coli O55:H7 and E. coli O55:NM, and other non-O157 SLT-producing E. coli strains. Primer design, reaction composition (in particular, primer quantity and ratios), and amplification profile were most important in development of this multiplex PCR. This assay can serve not only as a confirmation test but also potentially can be applied to detect the pathogen in food.