Establishment of fluorescent quantitative PCR assay for detection of Escherichia coli O_157∶H_7

Probes and primers for a TaqMan quantitative PCR were designed and synthesized according to the conserved gene sequence Stx1 and Stx2 of enterohemorrhagic E.coli(EHEC),available in GenBank.Then reaction parameters were optimized to develop a TaqMan-quantitative PCR assay.The clinical tissue samples were examined by using the established TaqMan-quantitative PCR and the results were compared with that by conventional PCR.The established PCR could detect 7.06×103CFU/mL plasmid DNA and its sensitivity was 1×106 times higher than that of the conventional PCR.Eight samples were used to examine the gene Stx1 by the established PCR and conventional PCR and the results indicated that the positive rate for Stx1 gene by the established PCR was in accordance with that by the conventional PCR.