title: Rose Bengal- and Riboflavin-Mediated Photodynamic Therapy to Inhibit Methicillin-Resistant Staphylococcus aureus Keratitis Isolates.
abstract: OBJECTIVE
  To evaluate the in vitro efficacy of rose bengal- and riboflavin-mediated photodynamic therapy for inhibition of methicillin-resistant Staphylococcus aureus (MRSA) isolates.
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  Two different multidrug-resistant, clinical MRSA isolates were grown on nutrient agar, prepared in suspension, and adjusted to concentrations of 1.5 × 10(4) colony-forming units per milliliter. Bacterial suspensions were mixed with rose bengal, riboflavin, or water according to experimental group. Tested in triplicate, groups included: Group I, MRSA control; Group II, MRSA with 0.1% rose bengal; Group III, MRSA with 0.03% rose bengal; and Group IV, MRSA with 0.1% riboflavin. All experimental groups were exposed to 3 lighting conditions: dark, ambient room light for 30 minutes, and 5.4 J/cm(2) with either green light-emitting diode (LED) or ultraviolet-A (UV-A) irradiation. Plates were photographed at 72 hours and custom software measured bacterial growth inhibition.
  
  
  RESULTS
  Complete growth inhibition of both MRSA strains was demonstrated (1) for both rose bengal concentrations under ambient and green LED irradiation, and (2) for the 0.1% rose bengal in the dark. The 0.03% rose bengal in dark conditions showed complete inhibition of strain 2 but incomplete inhibition of strain 1. Riboflavin showed almost complete inhibition with UV-A irradiation but demonstrated minimal inhibition for both strains in dark and ambient light conditions.
  
  
  CONCLUSIONS
  Rose bengal- and riboflavin-mediated photodynamic therapy demonstrated complete growth inhibition in vitro of 2 multidrug-resistant MRSA strains. Rose bengal was also effective in dark and ambient conditions. These results may have implications for in vivo therapy.
authors.affiliation: Ophthalmic Biophysics Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida.
authors.forename: Francisco
authors.initials: F
authors.lastname: Halili
authors.affiliation: Ophthalmic Biophysics Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Arboleda
authors.affiliation: Ophthalmic Biophysics Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida.
authors.forename: Heather
authors.initials: H
authors.lastname: Durkee
authors.affiliation: Ophthalmic Biophysics Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida; L. V. Prasad Eye Institute, Hyderabad, India.
authors.forename: Mukesh
authors.initials: M
authors.lastname: Taneja
authors.affiliation: Ocular Microbiology Laboratory, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida; Anne Bates Leach Eye Hospital, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida. Electronic address: dmiller@med.miami.edu.
authors.forename: Darlene
authors.initials: D
authors.lastname: Miller
authors.affiliation: Ophthalmic Biophysics Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida.
authors.forename: Karam A
authors.initials: KA
authors.lastname: Alawa
authors.affiliation: Ophthalmic Biophysics Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida.
authors.forename: Mariela C
authors.initials: MC
authors.lastname: Aguilar
authors.affiliation: Anne Bates Leach Eye Hospital, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Amescua
authors.affiliation: Anne Bates Leach Eye Hospital, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida.
authors.forename: Harry W
authors.initials: HW
authors.lastname: Flynn
authors.affiliation: Ophthalmic Biophysics Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida; Anne Bates Leach Eye Hospital, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida; University of Liège, Department of Ophthalmology, CHU Sart-Tillman, Liège, Belgium.
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Parel
mesh_terms: D003320:Corneal Ulcer / Q000382:microbiology*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000494:pharmacology*; D012256:Riboflavin / Q000494:pharmacology*; D012395:Rose Bengal / Q000494:pharmacology*; D013203:Staphylococcal Infections / Q000382:microbiology*; D014466:Ultraviolet Rays
chemical_list: D017319:Photosensitizing Agents; D012395:Rose Bengal; D012256:Riboflavin