title: Comparison of UV C light and chemicals for disinfection of surfaces in hospital isolation units.
abstract: OBJECTIVE
  To determine the bactericidal effect on surfaces of ceiling- and wall-mounted UV C (UVC) light (wavelength, 254 nm) in isolation units, compared with standard hospital environmental cleaning and chemical disinfection during final disinfection after patients are treated for infections.
  
  
  METHODS
  Microbial samples were obtained from surfaces in isolation units (patient room, anteroom, and bathroom) before and after irradiation with UVC, chloramine disinfection, and standard hospital environmental cleaning. Samples were tested using standard contact plates.
  
  
  METHODS
  Four identical, negative air-pressure isolation units (patient room, anteroom, and bathroom) with a defined number of ceiling- and wall-mounted UVC light units. The UVC distribution was monitored in one isolation unit after irradiation for approximately 40 minutes, corresponding to doses ranging from 160 J/m2 in a shadowed area to 19,230 J/m2 at the mostly highly exposed site (which is high enough to inactivate most bacterial organisms, including spores).
  
  
  RESULTS
  UVC disinfection significantly reduced the number of bacteria on surfaces directly or indirectly exposed to UVC to a very low number, as did 5% chloramine disinfection alone (P<.001 for both). Completely shadowed areas in the isolation unit (eg, the bed rail, lockers, and mattresses) still required disinfection by chemicals.
  
  
  CONCLUSIONS
  Disinfection with UVC light may significantly reduce environmental bacterial contamination and thereby protect the next patient housed in an isolation room. UVC disinfection may not be used alone but is a good addition to chemical disinfection.
authors.affiliation: Department of Hospital Infections, Ullevål University Hospital, Oslo, Norway.
authors.forename: B M
authors.initials: BM
authors.lastname: Andersen
authors.forename: H
authors.initials: H
authors.lastname: Bånrud
authors.forename: E
authors.initials: E
authors.lastname: Bøe
authors.forename: O
authors.initials: O
authors.lastname: Bjordal
authors.forename: F
authors.initials: F
authors.lastname: Drangsholt
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000528:radiation effects; D015169:Colony Count, Microbial; D004202:Disinfectants; D006757:Hospital Units; D006801:Humans; D010356:Patient Isolation; D014466:Ultraviolet Rays
chemical_list: D004202:Disinfectants