title: Antimicrobial photodynamic activity of hypericin against methicillin-susceptible and resistant Staphylococcus aureus biofilms.
abstract: OBJECTIVE
  To evaluate the effectiveness of the photodynamic therapy using hypericin (HYP) against both planktonic and biofilm-forming Staphylococcus aureus.
  
  
  METHODS
  HYP photoactivity was evaluated against methicillin-susceptible and resistant S. aureus. Bacterial suspension or biofilm were preincubated with HYP and subjected to LED illumination. Viable bacteria were determined by colony counting.
  
  
  RESULTS
  Preincubation with HYP (5 min) plus light exposure (10 min) showed bactericidal effect against planktonic methicillin-susceptible S. aureus and methicillin-resistant S. aureus. Longer preincubation times (24 h) and time light exposure (30 min) were required to reach HYP-photoactivity against S. aureus biofilms. HYP-photoactivity was correlated to the biofilm production.
  
  
  CONCLUSIONS
  HYP could be a potential photosensitizer for the inactivation of staphylococcal biofilms forming on the surfaces accessible to visible light.
authors: Department of Microbiology, School of Medicine, Universidad de Sevilla, Sevilla, Spain.
authors: Isabel
authors: I
authors: García
authors: Sofía
authors: S
authors: Ballesta
authors: Yolanda
authors: Y
authors: Gilaberte
authors: Antonio
authors: A
authors: Rezusta
authors: Álvaro
authors: Á
authors: Pascual
mesh_terms: D000873:Anthracenes; D018441:Biofilms / Q000187:drug effects*; D015169:Colony Count, Microbial; D008027:Light; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D050296:Microbial Viability / Q000187:drug effects; D010569:Perylene / Q000031:analogs & derivatives* / Q000494:pharmacology; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development
chemical_list: D000873:Anthracenes; D017319:Photosensitizing Agents; D010569:Perylene; C004965:hypericin
keywords: Staphylococcus aureus; antimicrobial photodynamic therapy; antimicrobial resistance; medical devices infections