title: 207-nm UV light - a promising tool for safe low-cost reduction of surgical site infections. I: in vitro studies.
abstract: BACKGROUND
  0.5% to 10% of clean surgeries result in surgical-site infections, and attempts to reduce this rate have had limited success. Germicidal UV lamps, with a broad wavelength spectrum from 200 to 400 nm are an effective bactericidal option against drug-resistant and drug-sensitive bacteria, but represent a health hazard to patient and staff. By contrast, because of its limited penetration, ~200 nm far-UVC light is predicted to be effective in killing bacteria, but without the human health hazards to skin and eyes associated with conventional germicidal UV exposure.
  
  
  OBJECTIVE
  The aim of this work was to test the biophysically-based hypothesis that ~200 nm UV light is significantly cytotoxic to bacteria, but minimally cytotoxic or mutagenic to human cells either isolated or within tissues.
  
  
  METHODS
  A Kr-Br excimer lamp was used, which produces 207-nm UV light, with a filter to remove higher-wavelength components. Comparisons were made with results from a conventional broad spectrum 254-nm UV germicidal lamp. First, cell inactivation vs. UV fluence data were generated for methicillin-resistant S. aureus (MRSA) bacteria and also for normal human fibroblasts. Second, yields of the main UV-associated pre-mutagenic DNA lesions (cyclobutane pyrimidine dimers and 6-4 photoproducts) were measured, for both UV radiations incident on 3-D human skin tissue.
  
  
  RESULTS
  We found that 207-nm UV light kills MRSA efficiently but, unlike conventional germicidal UV lamps, produces little cell killing in human cells. In a 3-D human skin model, 207-nm UV light produced almost no pre-mutagenic UV-associated DNA lesions, in contrast to significant yields induced by a conventional germicidal UV lamp.
  
  
  CONCLUSIONS
  As predicted based on biophysical considerations, 207-nm light kills bacteria efficiently but does not appear to be significantly cytotoxic or mutagenic to human cells. Used appropriately, 207-nm light may have the potential for safely and inexpensively reducing surgical-site infection rates, including those of drug-resistant origin.
authors.affiliation: Center for Radiological Research, Columbia University Medical Center, New York, New York, United States of America.
authors.forename: Manuela
authors.initials: M
authors.lastname: Buonanno
authors.forename: Gerhard
authors.initials: G
authors.lastname: Randers-Pehrson
authors.forename: Alan W
authors.initials: AW
authors.lastname: Bigelow
authors.forename: Sheetal
authors.initials: S
authors.lastname: Trivedi
authors.forename: Franklin D
authors.initials: FD
authors.lastname: Lowy
authors.forename: Henry M
authors.initials: HM
authors.lastname: Spotnitz
authors.forename: Scott M
authors.initials: SM
authors.lastname: Hammer
authors.forename: David J
authors.initials: DJ
authors.lastname: Brenner
mesh_terms: D002470:Cell Survival / Q000528:radiation effects; D004249:DNA Damage / Q000528:radiation effects; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000528:radiation effects; D012867:Skin / Q000378:metabolism / Q000382:microbiology / Q000528:radiation effects; D013530:Surgical Wound Infection / Q000517:prevention & control / Q000628:therapy; D014466:Ultraviolet Rays; D014467:Ultraviolet Therapy / Q000191:economics