Development of PCR primers based on a fragment from randomly amplified polymorphic DNA for the detection of Escherichia coli O157:H7/NM

Serotype O157:H7 of EHEC is by far the most prevalent serotype associated with haemorrhagic colitis (HC) and haemolytic uremic syndrome (HUS). Although PCR methods aimed on the detection of genes associated with the pathogenicity of Escherichia coli O157:H7 have been reported, tests allowing the direct identification of this serotype are rare. In this study, we used RAPD-PCR tests to analyze strains of E. coli O157:H7 serotype, strains of non-pathogenic E. coli, and strains of other pathotypes, including enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC), enteroinvasive E. coli (EIEC), and enteroaggregation E. coli (EAggEC). One RAPD fragment co-shared by serotype O157:H7 strains was observed when 10-mer primer termed as OPQ3 was used. After sequencing this fragment, three primers were designed and combined to form two PCR primer pairs. These two primer pairs were highly specific to the strains belonging to E. coli O157:H7/NM (non-motile).