349. Methicillin-Resistant Staphylococcus aureus (MRSA) Surveillance Culture as a Predictor for MRSA-Ventilator Associated Pneumonia
Session: Poster Abstract Session: MRSA, MSSA, Enterococci
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
  • MRSA-PCR v3.pdf (1.1 MB)
  • Background: The Society of Healthcare Epidemiology of America recommends acute care hospitals implement a MRSA surveillance program and that colonized patients be in contact isolation. The majority of patients admitted to intensive care units (ICU) are tested for MRSA colonization via MRSA-polymerase chain reaction (PCR). Several studies suggest a strong association between MRSA colonization and subsequent MRSA infection. The purpose of this study is to determine if a relationship exists between admission nasal MRSA-PCR test and the likelihood of developing MRSA-ventilator associated pneumonia (VAP). If the positive predictive value (PPV) and negative predictive value (NPV) of the MRSA nasal screening tests are strong predictors for the likelihood of MRSA-VAP, this screen could be used to guide or modify empiric antibiotic therapy.

    Methods: This is a retrospective, multi-center study at two tertiary-care, academic medical centers in Indianapolis, Indiana. Inclusion criteria: specimen from bronchoalveolar lavage (BAL), mini-BAL, or tracheal aspirate, an admission MRSA-PCR test, and mechanical ventilation (MV) ≥48 hours prior to cultures. Exclusion criteria: age < 18, pregnancy, incarceration, MV at outside hospital, or concurrent MRSA infection. 

    Results: One hundred and eighty-six patients were included in this study. All patients had an admission nasal MRSA PCR result and 16 (8.6%) were positive for MRSA colonization. Ten of the 186 patients were found to have MRSA-VAP (5.4%). The sensitivity and specificity of the MRSA PCR test as a predictor of MRSA-VAP are 70.0% (95% confidence interval (CI) 35.4-91.9) and 94.9% (95% CI 90.2-97.5), respectively. The positive and negative predictive values are 43.8% (95% CI 20.8-69.4) and 98.2% (95% CI 94.5-99.5), respectively.

    Conclusion: These results are consistent with previous studies showing that negative MRSA colonization is a strong negative predictor of MRSA-VAP. A unique finding of our study demonstrates that the one-time admission nasal surveillance culture can be effectively used to predict MRSA-VAP compared to a more frequent surveillance protocol. Our results further strengthen the argument that in the absence of respiratory MRSA colonization, empiric MRSA coverage may not be warranted in patients with suspected VAP.

    Brandon Mullins, Pharm.D., Indiana University Health, Indianapolis, IN, Dusten T. Rose, Pharm.D., Pharmacy Services, Indiana University Health, University Hospital, Indianapolis, IN and Sandra Kuehl, Pharm.D., BCPS, Indiana University Health, University Hospital, Indianapolis, IN


    B. Mullins, None

    D. T. Rose, None

    S. Kuehl, None

    Findings in the abstracts are embargoed until 12:01 a.m. PST, Oct. 2nd with the exception of research findings presented at the IDWeek press conferences.