Vero cytotoxin-producing strains of Escherichia cob from children with haemolytic uraemic syndrome and their detection by specific

Faecal specimens from 66 children with haemolytic uraemic syndrome in the United Kingdom were examined for strains of Escherichia coli producing Vero cytotoxin (VT). Initially, conventional bacteriological methods were used to identify colonies of E. coli which were then tested for VT production. Subsequently, specific DNA probes for VT1 and VT2 were used in hybridisation tests to detect VTproducing E. coli (VTEC). VTEC strains were isolated from 19 cases and in 15 they belonged to serogroup 0157. Fourteen of these 0157 strains possessed the flagellar antigen H7 and one was non-motile. The VTEC strains from the remaining four cases belonged to serotypes 026:H11,0104:H2,0153:H25, and 0163:H19 together with a rough VT' strain with flagellar antigen H51. The 0157 strains hybridised with either the VT2 probe or both VT1 and VT2 probes. The other VTEC strains hybridised with either the VTl or VT2 probe. Confirmation of the production of VT1 and VT2 in vivo was obtained by the neutralisation of faecal VT with specific antisera raised against these two cytotoxins.