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

Abstract

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.