Both Host and Pathogen Factors Predispose to Escherichia coli Urinary-Source Bacteremia in Hospitalized Patients

• Published in: Clinical infectious diseases 2012-06, Vol.54 (12), p.1692-1698
• Main Authors: Marschall, Jonas, Zhang, Lixin, Foxman, Betsy, Warren, David K., Henderson, Jeffrey P.
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; and Commentaries; ARTICLES AND COMMENTARIES; Bacteremia; Bacteremia - epidemiology; Bacteremia - microbiology; Bacterial diseases; Bacterial sepsis; Bacteriuria; Biological and medical sciences; Blood; Capsules; Cohort Studies; E coli; Escherichia coli; Escherichia coli - genetics; Escherichia coli - isolation & purification; Escherichia coli - pathogenicity; Escherichia coli Infections - epidemiology; Escherichia coli Infections - microbiology; Escherichia coli Infections - pathology; Female; Genes; Human bacterial diseases; Humans; Indexing in process; Infectious diseases; Male; Medical sciences; Middle Aged; Mortality; Prevalence; Prospective Studies; Pyelonephritis; Risk Factors; Urinary tract; Urinary tract diseases; Urinary Tract Infections - complications; Urinary Tract Infections - microbiology; Urine - microbiology; Urogenital surgical procedures; Virulence; Virulence factors; Virulence Factors - genetics
• ISSN: 1058-4838; 1537-6591
• DOI: 10.1093/cid/cis252

Background. The urinary tract is the most common source for Escherichia coli bacteremia. Mortality from E. coli urinary-source bacteremia is higher than that from urinary tract infection. Predisposing factors for urinary-source E. coli bacteremia are poorly characterized. Methods. In order to identify urinary-source bacteremia risk factors, we conducted a 12-month prospective cohort study of adult inpatients with E. coli bacteriuria that were tested for bacteremia within ±1 day of the bacteriuria. Patients with bacteremia were compared with those without bacteremia. Bacterial isolates from urine were screened for 16 putative virulence genes using high-throughput dot-blot hybridization. Results. Twenty-four of 156 subjects (15%) had E. coli bacteremia. Bacteremic patients were more likely to have benign prostatic hyperplasia (56% vs 19%; P = .04), a history of urogenital surgery (63% vs 28%; P = .001), and presentation with hesitancy/retention (21% vs 4%; P = .002), fever (63% vs 38%; P = .02), and pyelonephritis (67% vs 41%; P = .02). The genes kpsMT (group II capsule) (17 [71%] vs 62 [47%]; P = .03) and prf (P-fimbriae family) (13 [54%] vs 40 [30%]; P = .02) were more frequent in the urinary strains from bacteremic patients. Symptoms of hesitancy/retention (odds ratio [OR], 7.8; 95% confidence interval [CI], 1.6-37), history of a urogenital procedure (OR, 5.4; 95% CI, 2-14.7), and presence of kpsMT (OR, 2.9; 95% CI, 1-8.2) independently predicted bacteremia. Conclusions. Bacteremia secondary to E. coli bacteriuria was frequent (15%) in those tested for it. Urinary stasis, surgical disruption of urogenital tissues, and a bacterial capsule characteristic contribute to systemic invasion by uropathogenic E. coli.