title: Air and surface contamination patterns of meticillin-resistant Staphylococcus aureus on eight acute hospital wards.
abstract: BACKGROUND
  Meticillin-resistant Staphylococcus aureus (MRSA) can be recovered from hospital air and from environmental surfaces. This poses a potential risk of transmission to patients.
  
  
  OBJECTIVE
  To investigate associations between MRSA isolates recovered from air and environmental surfaces with those from patients when undertaking extensive patient and environmental sampling.
  
  
  METHODS
  This was a prospective observational study of patients and their environment in eight wards of a 700-bed tertiary care hospital during 2010 and 2011. Sampling of patients, air and surfaces was carried out on all ward bays, with more extended environmental sampling in ward high-dependency bays and at particular times of the day. The genetic relatedness of isolates was determined by DNA microarray profiling and spa typing.
  
  
  RESULTS
  MRSA was recovered from 30/706 (4.3%) patients and from 19/132 (14.4%) air samples. On 9/132 (6.8%) occasions both patient and air samples yielded MRSA. In 32 high-dependency bays, MRSA was recovered from 12/161 (7.4%) patients, 8/32 (25%) air samples, and 21/644 (3.3%) environmental surface samples. On 10/132 (7.6%) occasions, MRSA was isolated from air in the absence of MRSA-positive patients. Patient demographic data combined with spa typing and DNA microarray profiling revealed four likely transmission clusters, where patient and environmental isolates were deemed to be very closely related.
  
  
  CONCLUSIONS
  Air sampling yielded MRSA on frequent occasions, especially in high-dependency bays. Environmental and air sampling combined with patient demographic data, spa typing and DNA microarray profiling indicated the presence of clusters that were not otherwise apparent.
authors: Department of Clinical Microbiology, Education and Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland.
authors: E
authors: E
authors: Creamer
authors: Microbiology Research Unit, Division of Oral Biosciences, School of Dental Science and Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Ireland; Department of Clinical Microbiology, School of Medicine, University of Dublin, Trinity College, St James's Hospital, Dublin, Ireland.
authors: A C
authors: AC
authors: Shore
authors: Microbiology Research Unit, Division of Oral Biosciences, School of Dental Science and Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Ireland.
authors: E C
authors: EC
authors: Deasy
authors: Department of Clinical Microbiology, Education and Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland.
authors: S
authors: S
authors: Galvin
authors: Department of Clinical Microbiology, Education and Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland.
authors: A
authors: A
authors: Dolan
authors: Department of Clinical Microbiology, Education and Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland.
authors: N
authors: N
authors: Walley
authors: Department of Surgery, The Royal College of Surgeons in Ireland and Beaumont Hospital, Dublin, Ireland.
authors: S
authors: S
authors: McHugh
authors: Department of Clinical Microbiology, Education and Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland.
authors: D
authors: D
authors: Fitzgerald-Hughes
authors: Microbiology Research Unit, Division of Oral Biosciences, School of Dental Science and Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Ireland.
authors: D J
authors: DJ
authors: Sullivan
authors: Health Protection Surveillance Centre, Dublin, Ireland; Department of Microbiology, Children's University Hospital, Dublin, Ireland.
authors: R
authors: R
authors: Cunney
authors: Department of Clinical Microbiology, School of Medicine, University of Dublin, Trinity College, St James's Hospital, Dublin, Ireland.
authors: D C
authors: DC
authors: Coleman
authors: Department of Clinical Microbiology, Education and Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland; Department of Microbiology, Beaumont Hospital, Dublin, Ireland. Electronic address: hhumphreys@rcsi.ie.
authors: H
authors: H
authors: Humphreys
mesh_terms: D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000235:genetics; D004783:Environmental Microbiology; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D046228:Microarray Analysis; D058889:Molecular Typing; D011446:Prospective Studies; D062606:Tertiary Care Centers
chemical_list: D004269:DNA, Bacterial
keywords: Air sampling; Cross-transmission; DNA microarray profiling; Environmental sampling; Meticillin-resistant Staphylococcus aureus; spa typing