title: Reduction in MRSA environmental contamination with a portable HEPA-filtration unit.
abstract: There is renewed interest in the hospital environment as a potentially important factor for cross-infection with methicillin-resistant Staphylococcus aureus (MRSA) and other nosocomial pathogens. The aim of this study was to evaluate the effectiveness of a portable high-efficiency particulate air (HEPA)-filtration unit (IQAir Cleanroom H13, Incen AG, Goldach, Switzerland) at reducing MRSA environmental surface contamination within a clinical setting. The MRSA contamination rate on horizontal surfaces was assessed with agar settle plates in ward side-rooms of three patients who were heavy MRSA dispersers. Contamination rates were measured at different air filtration rates (60-235 m(3)/h) and compared with no air filtration using Poisson regression. Without air filtration, between 80% and 100% of settle plates were positive for MRSA, with the mean number of MRSA colony-forming units (cfu)/10-h exposure/plate ranging from 4.1 to 27.7. Air filtration at a rate of 140 m(3)/h (one patient) and 235 m(3)/h (two patients), resulted in a highly significant decrease in contamination rates compared with no air filtration (adjusted rate ratios 0.037, 0.099 and 0.248, respectively; P < 0.001 for each). A strong association was demonstrated between the rate of air filtration and the mean number of MRSA cfu/10-h exposure/plate (P for trend < 0.001). In conclusion, this portable HEPA-filtration unit can significantly reduce MRSA environmental contamination within patient isolation rooms, and this may prove to be a useful addition to existing MRSA infection control measures.
authors.affiliation: Department of Microbiology, Nottingham City Hospital, UK. tboswell@ncht.trent.nhs.uk
authors.forename: T C
authors.initials: TC
authors.lastname: Boswell
authors.forename: P C
authors.initials: PC
authors.lastname: Fox
mesh_terms: D000328:Adult; D000368:Aged; D000389:Air Conditioning / Q000295:instrumentation*; D000391:Air Microbiology; D000393:Air Pollutants / Q000009:adverse effects*; D003428:Cross Infection / Q000382:microbiology / Q000517:prevention & control*; D004867:Equipment Design; D004865:Equipment and Supplies, Hospital; D005374:Filtration / Q000295:instrumentation*; D006272:Health Facility Environment; D006801:Humans; D017053:Infection Control / Q000379:methods*; D008297:Male; D016106:Methicillin Resistance; D008875:Middle Aged; D013203:Staphylococcal Infections / Q000517:prevention & control*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000302:isolation & purification / Q000472:pathogenicity*
chemical_list: D000393:Air Pollutants