title: Antimicrobial blue light inactivation of Pseudomonas aeruginosa by photo-excitation of endogenous porphyrins: In vitro and in vivo studies.
abstract: Pseudomonas aeruginosa is among the most common pathogens that cause nosocomial infections and is responsible for about 10% of all hospital-acquired infections. In the present study, we investigated the potential development of tolerance of P. aeruginosa to antimicrobial blue light by carrying 10 successive cycles of sublethal blue light inactivation. The high-performance liquid chromatographic (HPLC) analysis was performed to identify endogenous porphyrins in P. aeruginosa cells. In addition, we tested the effectiveness of antimicrobial blue light in a mouse model of nonlethal skin abrasion infection by using a bioluminescent strain of P. aeruginosa. The results demonstrated that no tolerance was developed to antimicrobial blue light in P. aeruginosa after 10 cycles of sub-lethal inactivation. HPLC analysis showed that P. aeruginosa is capable of producing endogenous porphyrins in particularly, coproporphyrin III, which are assumed to be responsible for the photodynamic effects of blue light alone. P. aeruginosa infection was eradicated by antimicrobial blue light alone (48 J/cm(2) ) without any added photosensitizer molecules in the mouse model. In conclusion, endogenous photosensitization using blue light should gain considerable attention as an effective and safe alternative antimicrobial therapy for skin infections. Lasers Surg. Med. 48:562-568, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, 02114.|Department of Dermatology, Harvard Medical School, Boston, Massachusetts, 02114.|National Institute of Laser Enhanced Science, Cairo University, Giza, 12613, Egypt.
authors.forename: Rehab M
authors.initials: RM
authors.lastname: Amin
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, 02114.|Department of Dermatology, Harvard Medical School, Boston, Massachusetts, 02114.
authors.forename: Brijesh
authors.initials: B
authors.lastname: Bhayana
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, 02114.|Department of Dermatology, Harvard Medical School, Boston, Massachusetts, 02114.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hamblin
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, 02114.|Department of Dermatology, Harvard Medical School, Boston, Massachusetts, 02114.
authors.forename: Tianhong
authors.initials: T
authors.lastname: Dai
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004203:Disinfection / Q000379:methods*; D005260:Female; D008027:Light; D051379:Mice; D008807:Mice, Inbred BALB C; D010789:Phototherapy / Q000379:methods*; D011166:Porphyrins / Q000378:metabolism*; D011552:Pseudomonas Infections / Q000628:therapy*; D011550:Pseudomonas aeruginosa / Q000378:metabolism / Q000528:radiation effects*; D017192:Skin Diseases, Bacterial / Q000628:therapy*
chemical_list: D015415:Biomarkers; D011166:Porphyrins
keywords: Pseudomonas aeruginosa; blue light; drug resistance; endogenous porphyrins; mouse