A prospective study of exposure to verotoxin-producing Escherichia coli among Canadian children with haemolytic uraemic syndrome

Haemolytic uraemic syndrome (HUS) is a leading cause of acute renal failure in childhood. Although infection with Escherichia coli O 157.H7 has been associated with HUS in North America and Europe, only a limited number of studies have examined the role of other verotoxin-producing E. coli (VTEC) serotypes in this condition. To address this issue, we conducted a comprehensive, prospective microbiological study of patients treated for HUS at eight Canadian hospitals in the summer of 1990. Of the 34 consecutive patients with HUS enrolled over 4 months, E. coli O 157. H7 was isolated from the stools of 26, and other E. coli serotypes were isolated from four patients. In four subjects no pathogenic E. coli serotypes were identified on stool culture. Using oligonucleotide probes specific for VT-1 and VT-2, verotoxin genes were detected in the stool isolates of all patients with E. coli O 157.H7, and from two with other E. coli serotypes. Two other patients had at least a fourfold rise in anti-verotoxin antibodies. Strong evidence of exposure to a verotoxin was present in 30/34 (88 %). Patients with E. coli O 157. H7 infection were more likely to develop an antibody response to VT-2 than to VT-1 (22/22 vs 12/22; P = 0.002). These results further strengthen the association of HUS with verotoxin-producing E. coli in North America, and confirm that E. coli serotypes other than O 157. H7 are isolated in a small proportion of summertime HUS episodes.