489. Does Rapid Identification of Methicillin-Resistant Staphylococcus aureus (MRSA) Colonization upon Admission Modify the Duration of Empiric Vancomycin Use in the Medical Intensive Care Unit (MICU)?
Session: Poster Session: Hospital-acquired and Transplant Infections
Friday, October 30, 2009: 12:00 AM
Room: Poster Hall A
Objectives: To assess whether the presence or absence of MRSA colonization upon admission to the MICU aids clinicians in modifying the duration of empiric vancomycin therapy.
Methods: An observational study evaluating all MICU patients was conducted from 3/31/08 to 11/15/08 following the institution of active surveillance for MRSA at admission via nasal swab. Baseline demographics, prior history of MRSA infection, presence or absence of MRSA colonization utilizing nasal swab, duration of empiric vancomycin use, and incidence of MRSA infection during MICU stay were collected. Duration of empiric vancomycin use was compared to a historical cohort evaluated from 12/1/07 to 2/29/08. Study outcomes included prevalence of positive and negative nasal swabs in patients with no prior history of MRSA, incidence of MRSA infection, and duration of empiric vancomycin use.
Results: 446 patients were screened for MRSA upon admission via nasal swab. Excluding patients with a known positive MRSA history, 361 patients were MRSA negative and 30 were MRSA positive. Of the admission MRSA negative patients, 4 developed subsequent MRSA infection or colonization, resulting in a false negative rate of 1.1%. Overall, sensitivity, specificity, positive predictive value, and negative predictive value were 65%, 92%, 55%, and 95%, respectively. The mean duration of empiric vancomycin therapy in the admission negative MRSA group was 2.9 days compared to 3.4 days in the control group (p<0.05).
Conclusion: Negative MRSA colonization determined by nasal swab predicts a negative MRSA result by traditional culture. Active surveillance of MRSA status upon admission to the MICU reduces the duration of empiric vancomycin use in MRSA negative patients.
Molly Billstein, PharmD1, William Loeffler, PharmD1, Erica Tenholder, PharmD1, Jeffrey Topal, MD2, Jessica Vital, PharmD1 and  E. Tenholder, None..
W. Loeffler, None..
J. Vital, None..
M. Billstein, None..
J. Topal, None., (1)Yale-New Haven Hospital, New Haven, CT, (2)Section of Infectious Diseases, Yale School of Medicine, New Haven, CT