Abstract
OBJECTIVE: Bloodstream infection (BSI) secondary to nosocomial urinary tract infection is associated with substantial morbidity, mortality, and additional financial costs. Our objective was to identify predictors of nosocomial urinary tract-related BSI. DESIGN: Matched case-control study. SETTING: Midwestern tertiary care hospital. PATIENTS: Cases (n=298) were patients with a positive urine culture obtained more than 48 hours after admission and a blood culture obtained within 14 days of the urine culture that grew the same organism. Controls (n=667), selected by incidence density sampling, included patients with a positive urine culture who were at risk for BSI but did not develop one. Methods. Conditional logistic regression and classification and regression tree analyses. RESULTS: The most frequently isolated microorganisms that spread from the urinary tract to the bloodstream were Enterococcus species. Independent risk factors included neutropenia (odds ratio [OR], 10.99; 95% confidence interval [CI], 5.78-20.88), renal disease (OR, 2.96; 95% CI, 1.98-4.41), and male sex (OR, 2.18; 95% CI, 1.52-3.12). The probability of developing a urinary tract-related BSI among neutropenic patients was 70%. Receipt of immunosuppressants (OR, 1.53; 95% CI, 1.04-2.25), insulin (OR, 4.82; 95% CI, 2.52-9.21), and antibacterials (OR, 0.66; 95% CI, 0.44-0.97) also significantly altered risk. CONCLUSIONS: The heightened risk of urinary tract-related BSI associated with several comorbid conditions suggests that the management of nosocomial bacteriuria may benefit from tailoring to certain patient subgroups. Consideration of time-dependent risk factors, such as medications, may also help guide clinical decisions in reducing BSI.