Session: Poster Session: Assessing the Value of MRSA Screening
Monday, October 27, 2008: 12:00 AM
Room: Hall C
Background: Limiting hospital transmission of Methicillin-resistant Staphylococcus aureus (MRSA) has been achieved by improved hand hygiene, by initiation of contact precautions and patient isolation following screening for nasal carriage. A national beta-testing of a VA long term care (LTC) MRSA directive for VA LTC was initiated in February 2008 to see if these hospital interventions could be adapted to the LTC setting. We examined duration of exposure for roommate pairs based upon whether nasal colonization was concordant or discordant. Methods: Nasal swabs from residents of an 80-bed long term care facility were plated to BBL CHROMagar MRSA (Becton, Dickinson and Company, Sparks, MD); we also determined the bacterial burden of the resident, if positive, ranging from 1 (scant growth) to 6 (many colonies of MRSA). Results: Of 84 residents, 29 (34%) residents were MRSA screen (+). For residents in the 32 rooms with at least double occupancy, we determined if there were discordant results of MRSA screening before any resident movement or isolation began. There were 19 discordant rooms in the NH where one resident was positive and the other MRSA screen (-); 3 rooms where both residents were MRSA (+); and 10 rooms where both residents were MRSA (-). The discordances occurred in residents who had been living together for an average of 132 days, range 10-355 days. The average bacterial burden of the MRSA (+) residents was 3.9 (on a scale of 1 to 6). Compared to rooms where both residents were MRSA screen (+), the residents with discordant results were roomed together for similar periods of time (121 days vs. 132 days, p=NS). Conclusions: The large number of discordant pairs, especially with long time residents suggests that in the LTC setting transmission from an MRSA carrier may not carry the same risk of transmission as described in acute care settings.