Shedding of Methicillin-Resistant Staphylococcus aureus (MRSA) by Hospitalized Patients during Procedures

BACKGROUND: Contaminated environmental surfaces contribute to transmission of healthcare-associated pathogens such as methicillin-resistant Staphylococcus aureus (MRSA). We hypothesized that medical and non-medical procedures facilitate environmental dissemination of MRSA in hospitalized patients. METHODS: We conducted an observational cohort study of hospitalized MRSA-colonized patients to determine the frequency of and risk factors for environmental shedding during procedures. Prior to each procedure, surfaces in the room and portable equipment used for procedures were disinfected. After procedures, high-touch surfaces and portable equipment were cultured; negative control cultures were collected after 1 hour in the absence of a procedure. Bivariate analyses were performed to identify factors associated with environmental shedding. RESULTS: Of 55 MRSA colonized patients, 22 (40%) had wounds and 25 (46%) had positive skin cultures. Environmental cultures were collected after 138 total procedures (range, 2 to 12 per patient). As shown in the figure, contamination of surfaces occurred frequently during procedures, but was uncommon in the absence of a procedure. Contamination occurred frequently on surfaces touched by personnel during procedures (12 of 38, 32% positive) and on portable equipment used for procedures (25 of 101, 25%). The presence of a wound was the only factor significantly associated with shedding (59% vs. 26%; P = 0.04). CONCLUSION: Environmental shedding of MRSA occurs frequently during medical and non-medical procedures in hospitalized patients. Our results suggest that there is a need for effective strategies to disinfect surfaces and equipment after procedures. DISCLOSURES: All authors: No reported disclosures.