Establishment of a Eu-TRFM Immunochromatographic Test Strip for Detection of Escherichia coli O157:H7

Abstract:

Objective The aim of this study is to establish a rapid, efficient, and sensitive method for the detection of Escherichia coli (E. coli) O157:H7.Method The 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC)-mediated method was used to conjugate antibodies with time-resolved fluorescent microspheres (markers), and a fluorescence reader was used for quantitative analysis and detection of E. coli O157:H7. The detection sensitivity was improved by optimizing the pH of buffer for labeling, the amount of time-resolved fluorescent microspheres, the mass concentration of T-line antibodies, and the incubation time of samples and labeled antibodies.Result Under the optimal conditions, the detection sensitivity for E. coli O157:H7 reached 3.2×10³ CFU/mL, which was 10~1 000 times higher than that of colloidal gold immunochromatography, and there was no cross-reaction with other 8 common food-borne pathogens. In addition, the established test strip demonstrated good detection performance for the real samples of artificially contaminated drinking water, milk, and beef.Conclusion The EU-TRFM immunochromatographic test strip is suitable for the detection of E. coli O157:H7.