386. The Epidemiology of Methicillin Resistant Staphylococcus aureus Bloodstream Infections (MRSA BSI) among Admitted Patients in Alberta, Canada
Session: Poster Abstract Session: MRSA, MSSA, Enterococci
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
  • SHEA2013_MRSA BSI_FINAL.pdf (129.9 kB)
  • Background: Methicillin Resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI) rates are used as an indicator of total MRSA infection rates in acute care facilities across Alberta, Canada. Alberta Health Services and Covenant Health provide all hospital care in the province of Alberta. The objective was to describe the population of acute care patients with MRSA-BSI.

    Methods: All individuals admitted to an acute care facility from April 2011 to March 2012 were prospectively surveyed for the laboratory-confirmed MRSA BSI. Demographic, facility, and microbiological data were collected on all cases. MRSA and BSI were independently classified as Hospital Acquired (HA) when MRSA or BSI were present more than 48 hours after admission; or Community Acquired (CA) when MRSA or BSI were present in the first 48 hours of admission. Data were analysed using STATA/IC 10.0 (StataCorp, Texas, 2007). Univariate comparisons were performed using Fisher’s Exact Test for categorical variables and the Student’s t test for continuous variables.

    Results: Close to 350,000 patients were hospitalized from April 2011 to March 2012 and 0.7% (2455) were identified as new MRSA cases. Nearly 6% had MRSA BSI (151/2455, 6.15%). Just over 1/3 (51/151, 34%) had HA-BSI while 66% had CA-BSI. The CA-BSI group were younger at 50.9 years (Interquartile range, IQR 39.6-63.6) while the HA-BSI group were 67.9 years (IQR 58.0-79.2). Of the patients with HA-BSI, 62.8% (32/51) had HA-MRSA while 23.5% (12/51) had CA-MRSA. Amongst the patients with clinical MRSA positive specimens, 19.9% (30/151) were from skin/soft tissue only, and 12.6% (19/151) were respiratory only. Nearly 25% of patients (39/151) had only screening cultures positive and 17.9% (27/151) had no other culture positive results.

    Conclusion: CA-BSI represents a large proportion of all MRSA BSI cases in Alberta acute care facilities. These patients are younger than those with HA-BSI. Clinically significant specimens are skin/soft tissue and respiratory, however most patients did not have other positive specimens  within 10 days of their BSI positive result. Standardized provincial surveillance definitions for HA/CA are important for the consistent classification of MRSA BSI to understand the epidemiology of new BSI with MRSA.

    Kathryn Bush, MSc, Infection Prevention and Control, Alberta Health Services, Calgary, AB, Canada, Geoffrey Taylor, MD, University of Alberta Hospital, Edmonton, AB, Canada, Jenine Leal, MSc, Pediatrics, University of Calgary, Calgary, AB, Canada, Elizabeth Henderson, PhD, Alberta Health Services, Calgary, AB, Canada and Infection Prevention and Control Surveillance Program, Alberta Health Services


    K. Bush, None

    G. Taylor, None

    J. Leal, None

    E. Henderson, None

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