[Loop-mediated isothermal amplification for detecting enterohemorrhagic Escherichia coli O157:H7: a comparison with PCR].

OBJECTIVE: To establish a rapid method of loop-mediated isothermal amplification (LAMP) for detecting enterohemorrhagic Escherichia coli (EHEC) O157:H7.

METHODS: Six primers that specifically recognized the rfbE gene of EHEC O157:H7 were designed. Under the optimized reaction conditions, LAMP and PCR were evaluated for the sensitivity and specificity in the detection of 39 laboratory samples of EHEC O157:H7 strains, and their detection results of contaminated fresh pork samples were compared.

RESULTS: LAMP assay correctly identified all the 7 EHEC O157:H7 strains and showed negative results for all the 32 non-EHEC O157:H7 strains. The detection limit of LAMP was much lower than that of rfbE-PCR (10 vs 100 cfu/ml). In the detection of the contaminated pork samples, both LAMP and PCR yielded results consistent with those by the conventional detection method.

CONCLUSION: The rfbE-based LAMP assay can serve as a rapid, sensitive, specific and low-cost means for detecting EHEC O157:H7 strain.