558. Comparison of the Risk Factors for Co-colonization with Methicillin-Resistant Staphylococcus aureus (MRSA): VR E. faecalis vs VR E. faecium
Session: Poster Abstract Session: MRSA Surveillance and Infection Prevention
Friday, October 21, 2011
Room: Poster Hall B1

Background: Eight out of 12 vancomycin-resistant Staphylococcus aureus (VRSA) cases were from Michigan (MI), and in most cases, VRE faecalis served as the vanA donor to S. aureus. VRE faecalis is unusually common at DMC. The objective of this study was to identify the risk factors independently associated with co-colonization with MRSA and VRE faecalis as opposed to VRE faecium.

Methods: Unique patients with VRE and MRSA isolated during calendar years 2008-09 at the DMC were included. Patients with VRE faecalis and MRSA co-colonization (defined as isolation of MRSA within 7 days of VRE) were compared with patients with VRE faecium and MRSA co-colonization.  

Results: 85 VRE faecalis and 51 VRE faecium patients co-colonized with MRSA were identified. The mean age of the cohort was 64.2 15.8 years, 94 (71.8%) were African American, 69 (51.1%) were diabetic, and 78 (58.2%) resided in institutions prior to admission. 26 (19.3%) were hemodialysis patients, and 85 (63.9%) had chronic skin ulcers. On admission, 108 (80.6%) lacked functional independence, and 97 (72.9%) had permanent devices. The median Charlson's score was 8 (IQR 4-10). 109 (80.3%) patients had exposure to antibiotics within the prior 3 months. 48 (35.3%) of strains of VRE and 53 (39.0%) strains of MRSA isolates recovered from wounds, and 35 MRSA isolates were recovered from the same wound specimen as VRE. In bivariate analysis, the following factors were more likely to be associated with MRSA co-colonization with VRE faecalis than VRE faecium: heart valve diseases (P=0.003), rapidly fatal state per McCabe score (P=0.002) and past history of malignancy (P=0.029). In multivariate analysis controlling for all bivariate predictors, heart valve disease (P=0.04; OR 3.07, 95% CI [1.04-9.06]) and presence of a rapidly fatal conditions at the time of admission (P=0.01; OR 5.40, 95% CI [1.49-19.56]) were independent predictors for co-colonization of MRSA and VRE faecalis as opposed to VRE faecium. In-hospital mortality rates were similar between the both groups (11.9% and 16.0% respectively).  

Conclusion: Patients with a high severity of acute illness and/or structural heart disease were at particularly high risk for co-colonization with MRSA and VRE faecalis and might serve as a reservoir for future VRSA strains.

Subject Category: N. Hospital-acquired and surgical infections, infection control, and health outcomes including general public health and health services research

Kayoko Hayakawa, MD, PhD, Dror Marchaim, MD, Bharath Sunkara, MD, Srinivasa Kamatam, MD, Amit Vahia, MS, Kavyashri Kodlipet Jagadeesh, MD, Jason Pogue, PharmD, Paul Lephart, PhD, Emily Martin, MPH, PhD, Michael Rybak, PharmD, MPH and Keith Kaye, MD, MPH, FIDSA, Detroit Medical Center (DMC) / Wayne State University, Detroit, MI


K. Hayakawa, None

D. Marchaim, None

B. Sunkara, None

S. Kamatam, None

A. Vahia, None

K. Kodlipet Jagadeesh, None

J. Pogue, None

P. Lephart, None

E. Martin, None

M. Rybak, None

K. Kaye, None

Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.