title: Intensive care unit environmental surfaces are contaminated by multidrug-resistant bacteria in biofilms: combined results of conventional culture, pyrosequencing, scanning electron microscopy, and confocal laser microscopy.
abstract: BACKGROUND
  Hospital-associated infections cause considerable morbidity and mortality, and are expensive to treat. Organisms causing these infections can be sourced from the inanimate environment around a patient. Could the difficulty in eradicating these organisms from the environment be because they reside in dry surface biofilms?
  
  
  OBJECTIVE
  The intensive care unit (ICU) of a tertiary referral hospital was decommissioned and the opportunity to destructively sample clinical surfaces was taken in order to investigate whether multidrug-resistant organisms (MDROs) had survived the decommissioning process and whether they were present in biofilms.
  
  
  METHODS
  The ICU had two 'terminal cleans' with 500 ppm free chlorine solution; items from bedding, surrounds, and furnishings were then sampled with cutting implements. Sections were sonicated in tryptone soya broth and inoculated on to chromogenic plates to demonstrate MDROs, which were confirmed with the Vitek2 system. Genomic DNA was extracted directly from ICU samples, and subjected to polymerase chain reaction (PCR) for femA to detect Staphylococcus aureus and the microbiome by bacterial tag-encoded FLX amplicon pyrosequencing. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) were performed on environmental samples.
  
  
  RESULTS
  Multidrug-resistant bacteria were cultured from 52% (23/44) of samples cultured. S. aureus PCR was positive in 50%. Biofilm was demonstrated in 93% (41/44) of samples by CLSM and/or SEM. Pyrosequencing demonstrated that the biofilms were polymicrobial and contained species that had multidrug-resistant strains.
  
  
  CONCLUSIONS
  Dry surface biofilms containing MDROs are found on ICU surfaces despite terminal cleaning with chlorine solution. How these arise and how they might be removed requires further study.
authors.affiliation: Surgical Infection Research Group, Faculty of Medicine and Health Sciences, Macquarie University, New South Wales, Australia.
authors.forename: H
authors.initials: H
authors.lastname: Hu
authors.affiliation: Surgical Infection Research Group, Faculty of Medicine and Health Sciences, Macquarie University, New South Wales, Australia; Division of Microbiology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia.
authors.forename: K
authors.initials: K
authors.lastname: Johani
authors.affiliation: Antibiotic Resistance and Mobile Elements Group (ARMEG), Microbiology and Infectious Diseases Unit, School of Medicine, University of Western Sydney, New South Wales, Australia; Department of Microbiology and Infectious Diseases, Sydney South-West Pathology Service - Liverpool, New South Wales, Australia.
authors.forename: I B
authors.initials: IB
authors.lastname: Gosbell
authors.affiliation: Surgical Infection Research Group, Faculty of Medicine and Health Sciences, Macquarie University, New South Wales, Australia.
authors.forename: A S W
authors.initials: AS
authors.lastname: Jacombs
authors.affiliation: Surgical Infection Research Group, Faculty of Medicine and Health Sciences, Macquarie University, New South Wales, Australia; Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Qassim, Saudi Arabia.
authors.forename: A
authors.initials: A
authors.lastname: Almatroudi
authors.affiliation: Whiteley Corporation, Tomago, Newcastle, NSW, Australia.
authors.forename: G S
authors.initials: GS
authors.lastname: Whiteley
authors.affiliation: Surgical Infection Research Group, Faculty of Medicine and Health Sciences, Macquarie University, New South Wales, Australia.
authors.forename: A K
authors.initials: AK
authors.lastname: Deva
authors.affiliation: Antibiotic Resistance and Mobile Elements Group (ARMEG), Microbiology and Infectious Diseases Unit, School of Medicine, University of Western Sydney, New South Wales, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Jensen
authors.affiliation: Surgical Infection Research Group, Faculty of Medicine and Health Sciences, Macquarie University, New South Wales, Australia. Electronic address: Karen.vickery@mq.edu.au.
authors.forename: K
authors.initials: K
authors.lastname: Vickery
mesh_terms: D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D003428:Cross Infection / Q000382:microbiology* / Q000635:transmission; D024901:Drug Resistance, Multiple, Bacterial; D016983:Enterococcus / Q000254:growth & development / Q000302:isolation & purification; D006801:Humans; D007362:Intensive Care Units / Q000592:standards*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology; D064307:Microbiota; D018613:Microscopy, Confocal / Q000379:methods; D008855:Microscopy, Electron, Scanning / Q000379:methods; D015995:Prevalence; D013211:Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology
keywords: Biofilm; Enterococci; Healthcare-associated infections; Intensive care unit; Microbiome; Multidrug-resistant organisms; Staphylococcus aureus