Detection of Escherichia coli O157:H7 using chicken immunoglobulin Y

A sandwich ELISA technique was examined to detect Escherichia coli O157:H7 using chicken anti-E. coli O157:H7 IgY as the capture-antibody and an anti-E. coli O157 mouse mAb conjugated with biotin as the detection antibody. The anti-E. coli O157:H7 IgY was harvested from eggs laid by hens (23 weeks of age, Single Comb White Leghorn) immunized with formalin-killed E. coli O157:H7. The IgY was purified by water dilution methods and gel chromatography on Sephacryl S-300 followed by ammonium sulfate precipitation. The sensitivity (CFU/ml) of sandwich ELISA for the E. coli O157:H7 was repeatedly examined with 10 replicates of each sample and a standard curve was plotted. The sandwich ELISA can detect as low as 40CFU/ml of E. coli O157:H7. The data suggest that chicken IgY-based sandwich ELISA provides a reliable, inexpensive and sensitive assay for the detection of the food-borne pathogen E. coli O157:H7.