Studies on the development and use of a monoclonal sandwich ELISA for the detection of verotoxic Escherichia coli in animal faeces

Abstract
A sandwich ELISA using monoclonal antibodies to Escherichia coli verocytotoxins 1 and 2 for capture and detection was developed for detection of verocytotoxin-producing Escherichia coli (VTEC) in animal faeces. For optimal toxin detection, the faeces were cultured in MacConkey broth before subculture on to trypticase soy agar containing mitomycin C. It was possible to detect between 10 and 103 VT1-producing and 1 to 10 VT2-producing E coli/g faeces, and overall the sensitivity and specificity of the ELISA for VTEC in faeces were 80.5 per cent and 91.2 per cent, respectively, when compared with a verocell assay. A limited survey of faeces from healthy animals (89 cattle, 16 sheep, 22 pigs, 11 goats and six domestic fowl) and faeces from 144 cattle with enteric disease detected VTEC in 64 per cent, 63 per cent, 5 per cent, 45 per cent, none and 16 per cent of the samples, respectively.