Development of a monoclonal sandwich ELISA for the detection of animal andhuman 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 lipopolysa ccharide of E. coli O157. A sELISA developed with the MAb reacted with 28 b ovine and seven human enterohaemorrhagic E. coli (EHEC) O157 strains and al so with two enterotoxigenic E. coli O157 strains. Cross-reaction to a rabbi t 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 ap plication to field samples is required to fully determine its prospective u se for the detection of EHEC O157, to evaluate the non-specific interferenc e of the cross-reacting strains. Significance and Impact of the Study: The assay produced is not wholly spec ific to EHEC O157, but has the potential to be used as a rapid method for s creening large numbers of samples for E. coli O157.