Epidemic outbreaks of acute pyelonephritis caused by nosocomial spread of P fimbriated Escherichia coli in children.

In a study of pyelonephritis in children less than two years of age we found a high incidence of acute first-time pyelonephritis among children who had been previously cared for in a particular hospital neonatal ward. In 1981 and 1982 more than 50% of the children with pyelonephritis from the referral area of Danderyd Hospital (Danderyd, Sweden) had previously attended this particular neonatal ward; the expected incidence was 15% (P less than .001). The majority of these cases of pyelonephritis were caused by Escherichia coli that were P fimbriated and of serotype O6:K5. An E. coli strain with the same characteristics was found in the stools of personnel in the neonatal ward and in a high proportion of the stools and cord stumps of neonates in the ward. These findings support the opinion that certain P fimbriated E. coli clones may be nosocomially spread and cause epidemic outbreaks of pyelonephritis and that fecal colonization with such E. coli predisposes to this disease.