482. Ongoing Multi-clonal Dissemination of Methicillin Resistant Staphylococcus aureus (MRSA) Soft Tissue Infections in A Veterans' Long Term Care Facility (LTCF)
Session: Poster Session: Hospital-acquired and Transplant Infections
Friday, October 30, 2009: 12:00 AM
Room: Poster Hall A
Background: The G.V.”Sonny” Montgomery VA Medical Center has a 120 bed LTCF physically attached to a 165 bed acute care hospital. An ongoing cluster of MRSA soft tissue infections (INF) began in 10/05.
Methods: 1)Retrospective review (10/2005 - 4/2009) of MRSA surveillance, patient records and interventions. 2)Automated repetitive sequence based (rep)PCR system (DiversiLab, Biomerieux, Inc.) used for strain characterization of randomly selected isolates causing infection. 3)mec A and the Panton Valentine Leukocidin (PVL) gene independently verified by in-house PCR.
Results: INF began and predominated on one floor but by 2008 INF occurred on both floors. Eighty-eight MRSA INF were diagnosed in 54 patients. Of these INF, 63% were skin/soft tissue INF; Nasal carriage ranged from 5-17%. In fiscal year (FY) 2006(10/05-9/06), FY2007, FY2008 INF rates per 1000 bed days of care were 0.3 (n = 17), 0.84 (n=35) and 0.7 (n=26) respectively. Sixty% of INF occurred in patients with prior MRSA. Thirty had nose cultures 14 days before or after their primary infection; 60% were positive. Interventions with patient nasal surveys, decolonization, employees gowning during bathing of patients, and education on hand washing and environmental cleanliness were all initiated with limited overall effect. In response to geographic clusters employee nasal survey and decolonization was done with time limited decrease in INF. In 7/2008, gown and glove use with every in-room MRSA infected patient interaction was initiated. No skin INF have occurred in 5 of the past 6 months.
Among 23 isolates tested, all had mec A gene by both in-house PCR and rep-PCR. Four were tested for and had PVL gene. At least four major hierarchical isolate groups were identified by rep-PCR. One group of 5 indistinguishable isolates and 5 related isolates were a source of INF from 4/06 - 12/08.
Conclusion: Related strains persist in causing MRSA INF in this LTCF. Strain typing of isolates may identify unsuspected clusters allowing more specific intervention measures. Gown and gloves for each MRSA infected patient in-room interaction may help control these INF.
G.V. "Sonny" Montgomery MRSA Team, Rathel Nolan III, MD, University of Mississippi Medical Center, Jackson, MS, Chere Peel, MD, G.V. "Sonny" Montgomery VA Medical Center, Jackson, MS, Donna Sullivan, PhD, Univ MS Med Ctr, Jackson, MS, Risa Webb, MD, DTMH, Gail Woods, PhD, Arkansas VA Medical Center, Little Rock, AR and  R. M. Webb, None..
D. Sullivan, None..
R. Nolan, None..
G. Woods, None..
C. Peel, None.