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In published studies, cohorts of patients with bacteremia due to vancomycin-resistant Enterococcus (VRE) have predominantly been infected with Enterococcus faecium . Little is known about the epidemiology and outcomes associated with bacteremia due to VR Enterococcus faecalis . A retrospective study of isolates obtained from January 2008 to October 2010 was conducted at Detroit Medical Center (DMC). Unique patients with blood cultures positive for VRE were reviewed. Outcomes were analyzed using logistic regression. During the study period, 105 cases of bacteremia due to VR E. faecalis and 197 cases of bacteremia due to VR E. faecium were identified. The mean age in the study cohort was 61.5 ± 15 years; 162 subjects (53.6%) were male. After controlling for a propensity score, bacteremia due to VR E. faecalis was associated with >2-fold-lower in-hospital mortality than bacteremia due to VR E. faecium . Interestingly, bacteremia due to VR E. faecalis was associated with longer hospital stay after VRE isolation, although total length of stay was similar for groups with VR E. faecalis and VR E. faecium . Bacteremia due to VR E. faecalis was associated with a >2-fold-lower risk for mortality than bacteremia due to VR E. faecium , possibly due to the availability of β-lactam therapeutics for treatment of VR E. faecalis .

In the majority of cases of vancomycin-resistant Staphylococcus aureus (VRSA), vancomycin-resistant Enterococcus faecalis (VR E. faecalis) served as the vanA donor to S. aureus. Previous studies that evaluated the risk factors for co-colonization with VRE and MRSA did not differentiate between VR E. faecalis and VR E. faecium. This study aimed to identify variables associated with VR E. faecalis and MRSA co-colonization. A retrospective case-control study from January 2008 to December 2009 was conducted at the Detroit Medical Center. Data were extracted from charts and pharmacy records. Unique patients co-colonized with VR E. faecalis and MRSA (defined as isolation of MRSA within 7 days of VR E. faecalis isolation) were compared with patients with VR E. faecalis who were not co-colonized with MRSA. A total of 546 patients with VR E. faecalis isolation were identified. 85 (15.6 %) VR E. faecalis patients were co-colonized with MRSA and 461 (84.4 %) VR E. faecalis patients were not co-colonized with MRSA. The mean age of the study cohort was 65.9 ± 16.4 years, 424 (77.7 %) were African-American, and 270 (49.5 %) were residing in long-term care institutions. Independent predictors of co-colonization of VR E. faecalis and MRSA were male gender, impaired consciousness, ICU stay prior to VR E. faecalis isolation, indwelling devices, and isolation of VR E. faecalis from wounds. MRSA was frequently isolated from the same culture specimen as VR E. faecalis (n = 39, 45.9 %), most commonly from wounds. This large study of patients with VR E. faecalis identified the severity of illness, indwelling devices, and chronic wounds as independent predictors of co-colonization with VR E. faecalis and MRSA.

A retrospective case–case control study was conducted, including 60 cases with daptomycin-nonsusceptible vancomycin-resistant enterococci (DNS-VRE) matched to cases with daptomycin-susceptible VRE and to uninfected controls (1:1:3 ratio). Immunosuppression, presence of comorbid conditions, and prior exposure to antimicrobials were independent predictors of DNS-VRE, although prior daptomycin exposure occurred rarely. In summary, a case–case control study identified independent risk factors for the isolation of DNS-VRE: immunosuppression, multiple comorbid conditions, and prior exposures to cephalosporines and metronidazole.