[Development of a gold-immunochromatography test for rapid detecting E. coli O157].

Objective: To develop a method for rapid detecting Escherichia coli (E. coli) O157 on site.

Methods: A colloidal gold immunochromatography test based on double-antibody sandwich assay for detecting E. coli O157 was developed. Its sensitivity and specificity were then evaluated, and its feasibility of screening food samples were evaluated by analyzing various samples added with E. coli O157.

Results: Typical detecting time is less than 15 minutes per sample. The sensitivity of the test is 1 x 10(5) cfu/ml. No any cross-reaction with 30 strains of 24 species in Enterobacteriaceae (including non-O157 E. coli, Salmonella, Shigella, Proteus, Citrobacter, Enterobacter, Serratia and Yersinia), Staphylococus, Listeria, Aeromonas and Vibrios was found. The test could be used to detect E. coli O157 in various samples such as milk powder, flour, starch, coffee, biscuit, cake, jelly and juice.

Conclusion: The gold-immunochromatography test appears to be a rapid, convenient, specific and sensitive test for detecting E. coli O157: H7 on site.