Comparison of mortality associated with vancomycin-resistant and vancomycin-susceptible enterococcal bloodstream infections: A meta-analysis

Background. Whether vancomycin resistance is independently associated with mortality among patients with enterococcal bloodstream infection ( BSI) is controversial. To address this issue, we performed a systematic literature review with meta- analysis. Methods. Data sources were studies identified using the MEDLINE database ( for articles from 1988 through March 2003), the Cochrane Library ( for articles published up to March 2003), and bibliographies of identified articles. Inclusion criteria were that the study assessed mortality after enterococcal BSI, compared mortality after vancomycin- resistant enterococci ( VRE) BSI with that after vancomycin- susceptible enterococci ( VSE) BSI, and adjusted for severity of illness. Study exclusion criteria were as follows: no report of the adjusted measure of effect ( adjusted odds ratio [ OR], adjusted hazard ratio, or adjusted relative risk) of vancomycin resistance on mortality available and/ or its adjusted 95% confidence interval ( 95% CI). Data in the tables, figures, or text were independently extracted by 2 of the authors. Individual weights were calculated using the 95% CI of the adjusted measures of effect performing both fixed- effect and random- effects models. Results. Nine studies were eligible ( 11 studies met the inclusion criteria, and 2 were excluded), with a total of 1614 enterococcal BSI episodes ( 683 VRE episodes and 931 VSE episodes). Patients with bacteremia caused by VRE were more likely to die than were those with VSE bacteremia ( summary OR, 2.52; 95% CI, 1.9 - 3.4). Conclusions. Vancomycin resistance is independently associated with increased mortality among patients with enterococcal bloodstream infection.