Verocytotoxin-producing Escherichia coli infection in household members ofchildren with hemolytic-uremic syndrome in the Netherlands

Background. Strains of verocytotoxin-producing Escherichia coli (VTEC) belo nging to serogroup O157 (O157 VTEC) can cause a spectrum of disease that in cludes nonspecific diarrhea, hemorrhagic colitis and the diarrhea-associate d form of the hemolytic uremic syndrome (D+ HUS). Methods. We conducted a retrospective study of 34 children with D+ HUS caus ed by O157 VTEC to determine the frequency of VTEC infection in their house hold members. Results. Gastrointestinal tract symptoms were reported in 1 or more househo ld contacts of 17 (50%) of the 34 index cases. Of the 26 household members with gastrointestinal tract symptoms, 15 were parents and 11 were siblings. Evidence of VTEC infection was reported in 1 or more household contacts in 23 (68%) of the 34 families (in 46% of the siblings and in 28% of the pare nts). Nineteen (48%) siblings had a positive stool sample and in only 5 (12 %) of the siblings IgM class serum antibodies to O157-lipopolysaccharide (L PS) were detected. Nineteen (31%) parents had a positive stool sample. Anti bodies to O157-LPS were not detected in any of the parents. The occurrence of (bloody) diarrhea significantly correlated with the occurrence of IgM cl ass serum antibodies to O157-LPS. Conclusions. It was concluded that household members of children with D+ HU S are often asymptomatically infected with O157 VTEC. Differences in the pa thogenesis of the infection between infected individuals may be related to differences in the number of ingested O157 VTEC bacteria and to differences in susceptibility.