title: The correlation between airborne methicillin-resistant Staphylococcus aureus with the presence of MRSA colonized patients in a general intensive care unit.
abstract: Air sampling directly onto a methicillin-resistant Staphylococcus aureus (MRSA) selective agar was performed at six locations three times weekly over a period of 32 weeks in a new, initially MRSA-free Intensive Care Unit to examine if MRSA is present in air sample cultures and, if so, whether it is affected by the number of MRSA colonized patients present. A total of 480 air samples were collected on 80 days. A total of 39/480 (8.1%) samples were found to be MRSA positive of which 24/160 (15%) positive air samples were from the single rooms, where MRSA colonised patients were isolated, and 15/320 (4.7%) were from the open bed areas. A significant correlation was found between the daily number of MRSA colonized or infected patients in the Unit and the daily number of MRSA positive air samples cultures obtained (r2=0.128; P<0.005). The frequency of positive cultures was significantly higher in the single rooms than in the open bed areas (relative risk=3.2; P<0.001). The results from one of the single rooms showed a strong correlation between the presence of MRSA patients and MRSA positive air samples (relative risk=11.4; P<0. 005). Our findings demonstrate that the presence of airborne MRSA in our unit is strongly related to the presence and number of MRSA colonized or infected patients in the Unit.
authors.affiliation: Department of Intensive Care Medicine, University of Sydney, Nepean Hospital, Penrith, New South Wales.
authors.forename: R D
authors.initials: RD
authors.lastname: Wilson
authors.forename: S J
authors.initials: SJ
authors.lastname: Huang
authors.forename: A S
authors.initials: AS
authors.lastname: McLean
mesh_terms: D000391:Air Microbiology; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology*; D006801:Humans; D017053:Infection Control; D007362:Intensive Care Units; D016106:Methicillin Resistance; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000635:transmission*; D013211:Staphylococcus aureus / Q000187:drug effects*