Epidemiological aspects of P-fimbriated E. coli. II. Variations in incidence of E. coli infections in children attending a neonatal ward.

In a retrospective study we found an increased incidence of E. coli septicemia and pyelonephritis among children cared for in a special neonatal ward during 1975 and 1976 compared to the following years. The study was undertaken because of a previously reported epidemic outbreak of E. coli pyelonephritis in children cared for in the same neonatal ward during 1979-1982. The increased incidence of infections seems to be caused by spread of one or several virulent E. coli strains in the ward. Two of the strains causing septicemia were saved. They showed a multiply resistant antibiotic pattern similar to most of the strains causing pyelonephritis among the children born at that time. Their serotype was O4:K3 and they were P-fimbriated. Septicemia occurred among high-risk infants at a mean age of five days, while pyelonephritis occurred among uncomplicated cases at a mean age of 3.9 months. The proposed spread of one or several virulent E. coli strains correlates to a high bed occupancy in the ward during that time. r = 0.38 (p less than 0.01).