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Although much is known about vancomycin-resistant (VR) Enterococcus faecium , little is known about the epidemiology of VR Enterococcus faecalis . The predilection of VR E. faecalis to transfer the vancomycin resistance determinant to Staphylococcus aureus is much greater than that of VR E. faecium . The epidemiology of VR E. faecalis has important implications regarding the emergence of vancomycin-resistant S. aureus (VRSA); 8 of 13 reported VRSA cases have been from Michigan. A retrospective case-case-control study was conducted at the Detroit Medical Center, located in southeastern Michigan. Unique patients with VR E. faecalis infection were matched to patients with strains of vancomycin-susceptible (VS) E. faecalis and to uninfected controls at a 1:1:1 ratio. Five hundred thirty-two VR E. faecalis cases were identified and were matched to 532 VS E. faecalis cases and 532 uninfected controls. The overall mean age of the study cohort ( n = 1,596) was 63.0 ± 17.4 years, and 747 (46.8%) individuals were male. Independent predictors for the isolation of VR E. faecalis (but not VS E. faecalis ) compared to uninfected controls were an age of ≥65 years, nonhome residence, diabetes mellitus, peripheral vascular disease, exposure to cephalosporins and fluoroquinolones in the prior 3 months, and immunosuppressive status. Invasive procedures and/or surgery, chronic skin ulcers, and indwelling devices were risk factors for both VR E. faecalis and VS E. faecalis isolation. Cephalosporin and fluoroquinolone exposures were unique, independent predictors for isolation of VR E. faecalis . A majority of case patients had VR E. faecalis present at the time of admission. Control of VR E. faecalis , and ultimately VRSA, will likely require regional efforts focusing on infection prevention and antimicrobial stewardship.

Background.This study aimed to identify risk factors associated with carbapenem-resistant Enterobacteriaceae (CRE) colonization among patients screened with rectal cultures upon admission to a hospital or long-term acute care (LTAC) center and to compare risk factors among patients who were screen positive for CRE at the time of hospital admission with those screen positive prior to LTAC admission.Methods.A retrospective nested matched case-control study was conducted from June 2009 to December 2011. Patients with recent LTAC exposure were screened for CRE carriage at the time of hospital admission, and patients admitted to a regional LTAC facility were screened prior to LTAC admission. Cases were patients with a positive CRE screening culture, and controls (matched in a 3:1 ratio to cases) were patients with negative screening cultures.Results.Nine hundred five cultures were performed on 679 patients. Forty-eight (7.1%) cases were matched to 144 controls. One hundred fifty-eight patients were screened upon hospital admission and 521 prior to LTAC admission. Independent predictors for CRE colonization included Charlson's score greater than 3 (odds ratio [OR], 4.85 [95% confidence interval (CI), 1.64–14.41]), immunosuppression (OR, 3.92 [95% CI, 1.08–1.28]), presence of indwelling devices (OR, 5.21 [95% CI, 1.09–2.96]), and prior antimicrobial exposures (OR, 3.89 [95% CI, 0.71–21.47]). Risk factors among patients screened upon hospital admission were similar to the entire cohort. Among patients screened prior to LTAC admission, the characteristics of the CRE-colonized and noncolonized patients were similar.Conclusions.These results can be used to identify patients at increased risk for CRE colonization and to help target active surveillance programs in healthcare settings.