Development of a monoclonal sandwich ELISA for the detection of animal and human Escherichia coli O157 strains

Aims: Production of a monoclonal antibody (MAb) to Escherichia coli O157 to develop a rapid test using a sandwich ELISA (sELISA) format. Methods and Results: A MAb (7A6) was developed to the long-chain lipopolysaccharide of E. coli O157. A sELISA developed with the MAb reacted with 28 bovine and seven human enterohaemorrhagic E. coli (EHEC) O157 strains and also with two enterotoxigenic E. coli O157 strains. Cross-reaction to a rabbit diarrhoeal E.coli O15, Citrobacter freundii, Salmonella urbana and Vibrio cholerae O1 Inaba was detected. Conclusions: A MAb-based sELISA to detect E. coli O157 was produced. Its application to field samples is required to fully determine its prospective use for the detection of EHEC O157, to evaluate the non-specific interference of the cross-reacting strains. Significance and Impact of the Study: The assay produced is not wholly specific to EHEC O157, but has the potential to be used as a rapid method for screening large numbers of samples for E. coli O157.