No abstract

In a three year study of children under 16 years with haemolytic uraemic syndrome faecal samples were examined for the presence of Verocytotoxin producing Escherichia coli (VTEC) using DNA probes and for free neutralisable Verocytotoxin in a Vero cell assay with specific antisera. There was evidence of VTEC infection in 58 of 185 (31%) samples. A total of 53 VTEC was identified from patients with haemolytic uraemic syndrome. Thirty eight VTEC belonged to serotype 0157:H7 or 0157:H-, 34 produced VT2 only, and four strains produced both VT1 and VT2. The remaining 15 VTEC belonged to nine different 0 serogroups; three strains produced VT1, 10 produced VT2, and two were positive for VT1 and VT2. Three control groups of patients without haemolytic uraemic syndrome were also examined. There was evidence of VTEC infection in 8%, 6%, and 4% of specimens from individuals with bloody diarrhoea, those with diarrhoea only, and healthy controls respectively. VTEC from the bloody diarrhoeal and diarrhoeal controls were 0157:H7 but those from the healthy controls could not be 0 serogrouped. This study confirms the association of VTEC, and particularly strains of 0157:H7, with haemolytic uraemic syndrome. Strains producing VT1, VT2, or both toxins were isolated, although over 94% of VTEC produced VT2 alone or together with VT1.

Summary. 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.

No abstract