Specific detection of a verotoxin 2 variant, VT2vp1, by a bead-enzyme-linked immunosorbent assay

A bead-enzyme-linked immunosorbent assay to specifically detect a Verotoxin 2 variant, VT2vp1, was developed. The sensitivity of the bead-ELISA was 200 pg/ml of the purified VT2vp1 and it did not react with 20 ng/ml of the purified VT2. The specificity of the bead-ELISA was examined with 107 strains of Verocytotoxin-producing Escherichia coli that include VT1-, VT2-, VT2vha-, VT2vhb- and VT2vp1-producing E. coli, and only VT2vp1-producing E. coli that were confirmed by VT2vp1-specific polymerase chain reaction gave positive results. It was noted that all 58 VT2vp1-producing E. coli strains were from pigs, but not from cows and humans.