K-3362. MRSA Nasal Colonization Status is a Poor Predictor of Nosocomial MRSA Infection
Session: Poster Session: Assessing the Value of MRSA Screening
Monday, October 27, 2008: 12:00 AM
Room: Hall C
Background: The Atlanta VA instituted routine nasal swabs on all hospital admissions in September 2007 as part of the VA directive to identify and isolate patients with a positive screen. We conducted this study to correlate the results of a nasal screen with concurrent or subsequent true MRSA infection. Methods: Nasal swabs from admission are screened by PCR and discharge swabs are screened by CHROMagar. We analyzed data for the following clinical situations: 1) admission screen positive (NS pos), admitted with MRSA infection (C-MRSA); 2) admission screen positive, developed nosocomial MRSA infection (N-MRSA); 3) admission screen negative (NS neg), admitted with MRSA infection; 4) admission screen negative and remained negative, developed nosocomial MRSA infection; and 5) admission screen negative, converted to nasal screen positive, developed nosocomial MRSA infection. Results: Since September 2007 a total of 3209 admission nasal screens were performed; of these, 462 were positive (14.4%). Of the 2747 admission negative screens, 60 converted to positive (2.2%). The number of MRSA infections in each of the 5 clinical situations noted above is summarized in the Table.
NS pos,
C- MRSA
NS pos,
N- MRSA
NS neg,
C- MRSA
NS neg>neg,
N-MRSA
NS neg>pos, N- MRSA
No. of inf.53131666
% of NS status11.52.80.60.210.0
A total of 69 patients were admitted with community-onset MRSA infections. During this same time period, we documented an additional 211 community onset MRSA infections in patients not admitted to the hospital. Of the 25 nosocomial infections, 13 were known to be colonized on admission. Conclusions: Community-onset MRSA infections account for the great majority of infections seen in our facility. The VA MRSA Directive conducting admission nasal swabs to detect MRSA is a poor predictor of the development of nosocomial MRSA infections.
Courtney Stafford, MPH, Atlanta VA Medical Center, Decatur, GA, David Rimland, MD, School of Medicine at UCLA, Decatur, GA, Ken Lowery, VA Medical Center, Robert Gaynes, MD, Emory University School of Medicine, Atlanta, GA and  D. Rimland, None.