title: Antimicrobial Blue Light Inactivation of Gram-Negative Pathogens in Biofilms: In Vitro and In Vivo Studies.
abstract: BACKGROUND
  Biofilms affect >80% bacterial infections in human and are usually difficult to eradicate because of their inherent drug resistance.
  
  
  METHODS
  We investigated the effectiveness of antimicrobial blue light (aBL) (wavelength, 415 nm) for inactivating Acinetobacter baumannii or Pseudomonas aeruginosa biofilms in 96-well microplates or infected mouse burn wounds.
  
  
  RESULTS
  In vitro, in 96-well microplates, exposure of 24-hour-old and 72-hour-old A. baumannii biofilms to 432 J/cm(2) aBL resulted in inactivation of 3.59 log10 and 3.18 log10 colony-forming units (CFU), respectively. For P. aeruginosa biofilms, similar levels of inactivation-3.02 log10 and 3.12 log10 CFU, respectively-were achieved. In mouse burn wounds infected with 5 × 10(6) CFU ofA. baumannii, approximately 360 J/cm(2) and 540 J/cm(2) aBL was required to inactivate 3 log10 CFU in biofilms when delivered 24 and 48 hours, respectively, after bacterial inoculation. High-performance liquid chromatography analysis revealed the presence of endogenous porphyrins in both A. baumannii and P. aeruginosa TUNEL assay detected no apoptotic cells in aBL-irradiated mouse skin at up to 24 hours after aBL exposure (540 J/cm(2)).
  
  
  CONCLUSIONS
  aBL has antimicrobial activity in biofilms ofA. baumannii and P. aeruginosa and is a potential therapeutic approach for biofilm-related infections.
authors.affiliation: Department of Laser Medicine, Chinese PLA General Hospital, Beijing College of Medicine, Nankai University, Tianjin Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Ximing
authors.initials: X
authors.lastname: Wu
authors.affiliation: Shanghai Dermatology Hospital, China Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Jia
authors.initials: J
authors.lastname: Chen
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Rehab
authors.initials: R
authors.lastname: Amin
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Min
authors.initials: M
authors.lastname: Lu
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Brijesh
authors.initials: B
authors.lastname: Bhayana
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Infectious Disease Service, Brooke Army Medical Center, Fort Sam Houston, Texas.
authors.forename: Clinton K
authors.initials: CK
authors.lastname: Murray
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hamblin
authors.affiliation: Division of Infectious Diseases, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: David C
authors.initials: DC
authors.lastname: Hooper
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Tianhong
authors.initials: T
authors.lastname: Dai
mesh_terms: D040981:Acinetobacter baumannii / Q000528:radiation effects*; D000818:Animals; D017209:Apoptosis / Q000528:radiation effects; D018441:Biofilms / Q000528:radiation effects*; D002056:Burns / Q000382:microbiology; D004195:Disease Models, Animal; D004203:Disinfection / Q000379:methods*; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology*; D008027:Light; D016014:Linear Models; D051379:Mice; D008807:Mice, Inbred BALB C; D061848:Optical Imaging; D011550:Pseudomonas aeruginosa / Q000528:radiation effects*; D014946:Wound Infection / Q000382:microbiology
keywords: Acinetobacter baumannii; HPLC; Pseudomonas aeruginosa; TUNEL assay; antimicrobial blue light; biofilm; bioluminescence imaging; burn wound; endogenous porphyrins; mouse model