P fimbriation of Escherichia coli strains from patients with urosepsis demonstrated by a commercial agglutination test (PF TEST)

We examined 138 Escherichia coli strains isolated from cultures of blood specimens from urosepsis patients (n = 78) and nonurosepsis patients (n = 30) and from fecal specimens of a healthy control group (n = 30) for P fimbriation with a mannose-resistant hemagglutination test, an indirect immunofluorescence assay, and a new commercial particle agglutination test (PF TEST; Orion Diagnostica, Espoo, Finland). About 60% of the strains in the urosepsis group were P fimbriated with all tests, with no significant differences observed between patients with or without known predisposing factors. In the non-urosepsis-associated and fecal strains, the incidence of P-fimbriated E. coli strains varied from 3.3% (PF TEST) to 33% (indirect immunofluorescence assay), depending on the test method. The PF TEST proved easy to perform and demonstrated a specificity and a sensitivity equal to those of the alternative tests. The PF TEST can be recommended for routine clinical use to detect virulent urinary E. coli strains.