Rapid detection of E.coli O157:H7 by immunocapture and loop-mediated isothermal amplification

Objective: To develop the method for the rapid detection of E.coli O157:H7 by immunocapture and loop-mediated isothermal amplification (LAMP) and to investigate their specificity and sensitivity. Method: The monoclonal antibody specific to E.coli O157 is established after screening and sub- cloning and is enveloped in ELISA plates to capture E.coli O157:H7 in the samples for extracting DNA templates. Basing on the fliC gene encoding the flagellum H7 of E.coli O157:H7 for the target sequences and utilize the detection system which is capable of performing both the amplification and detection (by fluorescence) of LAMP in one platform. Analysis color change to determine test results. Results: The specific detection was carried out in 3 strains of E.coli O157:H7 and 14 strains of non-E.coli O157:H7. It was found that all the 3 strains of E.coli O157:H7 showed positive results, whereas other strains showed negative results. The detecting sensitivity of E. coli O157: H7 was 2.5 cfu/mL. The detection limit of E.coli O157: H7 from artificial contamination milk was 8 cfu/mL. Conclusion: This kind of LAMP pretreatment method not only greatly shorten the time for increasing E.coli O157:H7 and it can improve the detection results of the accuracy and stability.