CHARACTERIZATION OF ESCHERICHIA-COLI ISOLATED IN BLOOD, URINE AND FECES FROM BACTEREMIC PATIENTS AND POSSIBLE SPREAD OF INFECTION

Blood, faecal and urine isolates from patients with culture-verified E. coli bacteraemia were investigated with respect to biochemical phenotype, O and K serotype and P. fimbriae. In 10/16 bacteraemic episodes, the blood isolates were identical to the corresponding faecal strains. In four of the remaining infections, antimicrobial therapy was initiated more than two days before faecal samples were taken. Urine cultures revealed growth of E. coli in 12/16 samples. However, only three had clinical signs of symptomatic urinary tract infections. Eight of these E. coli were saved. Further analysis revealed that five of eight strains were identical to the corresponding isolates from blood and stool samples, two were only identical to the faecal strain, while one was different to the corresponding E. coli in the blood and stool samples. The isolated E. coli strains belonged to varying and, among previously healthy persons, normally less common serotypes. No epidemiological relationship was observed between the studied strains. The high incidence of identical strains in the blood, stool and urine indicates a bacterial spread from the faecal flora directly to the urine and possibly also, via the blood, to the urine.