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612 Epidemology and Risk Factors for Bacteremia due to Vancomycin-resistant Enterococcus (VRE): E. faecalis compared to E. faecium

Sunday, April 3, 2011
Trinity Ballroom (Hilton Anatole)
Kayoko Hayakawa, MD, PhD , Detroit Medical Center, Wayne State University, Detroit, MI
Dror Marchaim, MD , Detroit Medical Center, Wayne State University, Detroit, MI
Jason M. Pogue, Pharm, D , Detroit Medical Center, Wayne State University, Detroit, MI
Paul R. Lephart, PhD , Detroit Medical Center, Wayne State University, Detroit, MI
Bharath Sunkara, MD , Detroit Medical Center, Wayne State University, Detroit, MI
Judy Moshos, MT , Detroit Medical Center, Wayne State University, Detroit, MI
Harikrishna Kotra, MBBS , Detroit Medical Center, Wayne State University, Detroit, MI
Asma Hasan, BS , Detroit Medical Center, Wayne State University, Detroit, MI
Maryann Shango, BS , Detroit Medical Center, Wayne State University, Detroit, MI
Yashwanth Yerramalla, MBBS , Detroit Medical Center, Wayne State University, Detroit, MI
Sarwan Kumar, MD , Detroit Medical Center, Wayne State University, Detroit, MI
Vicki Collins, MD , Detroit Medical Center, Wayne State University, Detroit, MI
Kimberley Ku, BS , Detroit Medical Center, Wayne State University, Detroit, MI
Palaniappan Manickam, MD, MPH , Detroit Medical Center, Wayne State University, Detroit, MI
Sagar Mallikethi Lepakshi Reddy, MBBS , Detroit Medical Center, Wayne State University, Detroit, MI
Kavyashri Kodlipet Jagadeesh, MBBS , Detroit Medical Center, Wayne State University, Detroit, MI
Verma Sourabh, MBBS , Detroit Medical Center, Wayne State University, Detroit, MI
Adedayo Morenike Omotola, MBBS , Detroit Medical Center, Wayne State University, Detroit, MI
Dhivya Sundaramurthy, MBBS , Detroit Medical Center, Wayne State University, Detroit, MI
Suchitha Bheemreddy, MD , Detroit Medical Center, Wayne State University, Detroit, MI
Jessie Swan, BS , Detroit Medical Center, Wayne State University, Detroit, MI
Lakisha Burton Willis, MBA , Detroit Medical Center, Wayne State University, Detroit, MI
Satyam Patel, MBBS , Detroit Medical Center, Wayne State University, Detroit, MI
Rupali Krishana , Detroit Medical Center, Wayne State University, Detroit, MI
Maninderpal Dhillon, BS , Detroit Medical Center, Wayne State University, Detroit, MI
Nimrit Sohal , Detroit Medical Center, Wayne State University, Detroit, MI
Hardik Doshi, MBBS , Detroit Medical Center, Wayne State University, Detroit, MI
Neelu Chugh, MBBS , Detroit Medical Center, Wayne State University, Detroit, MI
Miriam Levine, BA , Detroit Medical Center, Wayne State University, Detroit, MI
Victoria Yee, BS, MS , Detroit Medical Center, Wayne State University, Detroit, MI
Farah Ahmad, MD , Detroit Medical Center, Wayne State University, Detroit, MI
Umme Suhrawardy, MBBS , Detroit Medical Center, Wayne State University, Detroit, MI
Chika Okoronkwo, MD , Detroit Medical Center, Wayne State University, Detroit, MI
Teena Chopra, MD , Detroit Medical Center, Wayne State University, Detroit, MI
Sorabh Dhar, MD , Detroit Medical Center, Wayne State University, Detroit, MI
Keith .S Kaye, MD, MPH , Detroit Medical Center, Wayne State University, Detroit, MI

Background: Vancomycin-resistant S. aureus (VRSA) is a public health threat. Since 2002, 11 cases of VRSA have been reported in the US, including 8 from Southeast Michigan. VRSA results when the vanA gene complex transfers from vancomycin-resistant enterococci (VRE) to S. aureus.  This transfer is much more common in VRE faecalis than VRE faecium. The portion of VRE faecalis out of all VRE isolations in Southeast Michigan is disproportionally high (> 30%). VRE cohorts studied in the past primarily consisted of E. faecium isolates, with E. faecalis representing the minority of cases (<10% in most studies).   

Objective: To conduct an epidemiological investigation of VRE bacteremias caused by E. faecalis in the region that is most endemic in the world for VRSA isolation and to identify variables that differentiate VRE faecalis from faecium. 

Methods: A retrospective study for calendar years 2008-09 was conducted at Detroit Medical Center (DMC), an 8-hospital healthcare system located in Southeast Michigan. All unique patient VRE blood cultures were reviewed and analyzed.

Results: A total of 77 (33%) VRE faecalis and 159 (67%) VRE faecium bacteremias were diagnosed during the study period. The mean age of patients was 61±15 years, 131 (56%) were male, and 179 (76%) were African-Americans. Seventeen patients (22%) with bacteremia due to VRE faecalis died during their hospital stay, versus 54 (34%) patients with VRE faecium (p=0.06). In multivariate analysis, independent predictors for isolation of VRE faecalis (as opposed to VRE faecium) were chronic hemodialysis (OR=4.4, p<0.001), dependent functional status at baseline (OR=3.8, p=0.01), ≥4 weighted index of co-morbidities per Charlson's score (OR=2.6, p=0.02), presence of a rapidly fatal condition (OR=2.7, p=0.02), recent (3 months) exposure to glycopeptides (OR=3.7, p=0.001) or to trimethoprim/sulfamethoxazole (TMP/SMX) (OR=54.8, p<0.001), and being co-colonized with MRSA (OR=2.7, p=0.04). Acute liver injury during the acute illness was significantly associated with VRE faecium isolation, as opposed to VRE faecalis (OR 7.8, p=0.03).

Conclusions: Bacteremia due to VRE faecalis occurred more commonly in patients with underlying comorbid conditions and impaired functional status, when compared to patients with bacteremia due to VRE faecium. Exposure to glycopeptides and TMP/SMX were independent predictors for VRE faecalis compared to VRE faecium. Co-colonization with MRSA was much more common in VRE faecalis, which explains in part, why the Detroit region is associated with relatively high rates of VRSA.