520. Predictors of Prosthetic Joint Infection due to Methicillin-Resistant Staphylococcus aureus (MRSA)
Session: Poster Abstract Session: Surgical Site Infections
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
  • IDSA_PJI.pdf (60.3 kB)
  • Background: Staphylococcus aureus (SA) is one of the most common causes of prosthetic joint infection (PJI).  Infections due to MRSA are associated with particularly severe clinical outcomes.  The purpose of this study was to identify predictors of PJI due to MRSA as compared to methicillin-susceptible S. aureus (MSSA

    Methods: A retrospective cohort study was conducted at Detroit Medical Center (DMC), an 8-site healthcare system with over 2200 beds, from 06/2005-12/2011.  All patients who had SA isolated from tissue and wound cultures within one year of primary and/or revision surgeries were included. Surgeries of hip and/ or knee joints were included. CLSI breakpoints were used to define methicillin sensitive SA (MSSA) and methicillin resistance SA (MRSA).  Percents were calculated after excluding missing data.

    Results: Fifty-one patients with PJI due to MRSA were compared to 49 patients with MSSA.  Of these patients, 58 had undergone hip arthroplasty and 42 knee arthroplasty.  The most common indication for arthroplasty was degenerative joint disease in both MRSA and MSSA PJI.  However, femoral neck fracture was more frequently a reason for arthroplasty in the MRSA PJI group than in the MSSA PJI group (20% and 7%).The median time to diagnosis of PJI was 28 days (IQR 19-77). The proportion of PJI due to MRSA was 59% in the hip arthroplasty group and 41% in the knee arthroplasty group.  The mean age of the cohort was 58± 14 years, 49 (49%) were male and 52 (52%) were African American. Patents with PJI due to MRSA, as compared with MSSA, had an increased frequency of congestive heart failure (CHF) (22% and 4%, p=0.02); peripheral vascular disease (PVD) (28% and 7%, p=0.008) and renal impairment (16% and 2%, p=0.03).  Patients with MRSA PJI, compared to patients with MSSA PJI, more often had PJI categorized as organ/space (12% and 2%, p=0.12); and a length of stay during their surgical hospitalization (LOS) of > 3 days (68% and 46%, p=0.04). In multivariate analysis, independent predictors of PJI due to MRSA included PVD (OR=5.9, 95% CI 1.5-23.0), renal disease (OR=8.5, 95% CI 1.0-73) and LOS>3 days (OR=2.2, 95% CI 0.9-5.3).

    Conclusion: PJI due to MRSA was associated with underlying PVD, renal disease and LOS > 3 days.   These predictors of PJI due to MRSA can help to improve infection prevention efforts and decrease the time to effective therapy among patients with MRSA PJI.

    Ashish Bhargava, MD1, Beth Stallman2, Monica Saxena2, Harish Pulluru, MBBS1, Richmund Wenzel3, Joseph Ellsworth4, Elaine Flanagan, BSN, MSA5, Sorabh Dhar, MD1 and Keith Kaye, MD, MPH, FIDSA, FSHEA5, (1)Detroit Medical Center (DMC) / Wayne State University, Detroit, MI, (2)Wayne State University, Detroit, MI, (3)Wayne State University, detroit, MI, (4)Detroit Medical Center, Detroit, MI, (5)Infectious Diseases, Detroit Medical Center/ Wayne State University, Detroit, MI


    A. Bhargava, None

    B. Stallman, None

    M. Saxena, None

    H. Pulluru, None

    R. Wenzel, None

    J. Ellsworth, None

    E. Flanagan, None

    S. Dhar, None

    K. Kaye, None

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