Among 75 urosepsis isolates of Escherichia coli, 29 virulence factor (VF) genes were detected by use of a novel polymerase chain reaction (PCR) assay. Compared with probe hybridization, the PCR assay's specificity was 100% and sensitivity 97.1%. fyuA (yersiniabactin: overall prevalence, 93%), tra T (serum resistance, 68%), and a pathogenicity-associated island marker (71%) occurred in most strains from both compromised and noncompromised hosts. Present in <20% of strains each were sfaS, focG (F1C fimbriae), afaldra, bmaE (M fimbriae), gafD (G fimbriae), cnf1, cdtB (cytolethal distending toxin), cvaC (colicin V), and ibeA (invasion of brain endothelium). Different VFs were variously confined to virulence-associated phylogenetic group B2 (as defined by multilocus enzyme electrophoresis); concentrated in group B2, but with spread beyond; or concentrated outside of group B2. These findings provide novel insights into the VFs of extraintestinal pathogenic E. coli and demonstrate the new PCR assay's utility for molecular epidemiological studies.
Bibliographical noteFunding Information:
Received 13 August 1999; revised 27 September 1999; electronically published 23 December 1999. Presented in part: 36th Annual Meeting of the Infectious Diseases Society of America, Denver, CO, November 1998 (abstract 77). Financial support: VA Merit Review and NIH (DK-47504) to J.R.J. Reprints or correspondence: Dr. James R. Johnson, University of Minnesota Department of Medicine, Infectious Diseases (111F), Minneapolis VA Medical Center, 1 Veterans Dr., Minneapolis, MN 55417 (johns007@ maroon.tc.umn.edu).