Abstract:

Purpose: To establish a new rapid quantitative assay for detecting Escherichia coli O157:H7. Methods: Using
nitrocellulose membrane as substrate, an antibody macroarray was fabricated with a biochip spotting robot, and then a
double antibody sandwich method was developed for quantitative detection of E. coli O157:H7. Results: The limit of
detection (LOD) for E. coli O157:H7 was 3.4 × 105 CFU/mL, and a good linear relationship was observed between grey
value for the macroarray and bacterial concentration in the range of 105–107 CFU/mL. This method could allow simultaneous
determination of different concentrations of E. coli O157:H7 in multiple samples. Conclusions: As evaluated by applying
it to standard strains and simulated enrichment culture, the antibody macroarray-based method could provide stable and
accurate results visible to naked eyes with simple operation and low costs without the use of large equipment. Moreover, the
antibody macroarray developed in this study could be used to rapidly assess E. coli O157:H7 pollution in food, especially
suitable for rapid screening of samples in grassroots-level laboratories.

Key words: Escherichia coli O157:H7, antibody macroarray, visualization, quantitative determination