Impact of Vancomycin Resistance on Mortality among Patients with Neutropenia and Enterococcal Bloodstream Infection

We performed a retrospective cohort study to measure the impact of vancomycin resistance on clinical outcome for 83 episodes of enterococcal bloodstream infection (BSI; 22 with vancomycin-resistant enterococci VRE and 61 with vancomycin-susceptible enterococci VSE) in 77 patients with neutropenia. Cox proportional hazards models showed that vancomycin resistance was an independent predictor of mortality, after controlling for severity of illness, enterococcal species, gram-negative copathogens, sex, race, duration of neutropenia before bacteremia, and early administration of active antibiotics. This effect was evident only > or =10 days after the onset of bacteremia (P=.0263; hazard ratio HR, 4.969) but not after adjustment for duration of bacteremia. The median duration of bacteremia was 4.5 days for VRE BSI and <1 day for VSE BSI (P=.0001). The only independent predictor of bacteremia duration was vancomycin resistance (P=.0284; HR, 3.863). Vancomycin resistance is associated with increased mortality in patients with neutropenia, possibly because of prolonged duration of bacteremia.