title: Blue Laser Inhibits Bacterial Growth of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa.
abstract: OBJECTIVE
  The purpose of this study was to analyze the influence of blue laser on bacterial growth of the main species that usually colonize cutaneous ulcers, as well as its effect over time following irradiation.
  
  
  BACKGROUND
  The use of blue laser has been described as an adjuvant therapeutic method to inhibit bacterial growth, but there is no consensus about the best parameters to be used.
  
  
  METHODS
  Strains of Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, and Escherichia coli ATCC 25922 were suspended in saline solution at a concentration of 1.5×10(3) colony forming units (CFU)/mL. Next, 300 μL of this suspension was transferred to a microtitulation plate and exposed to a single blue laser irradiation (450 nm) at fluences of 0 (control), 3, 6, 12, 18, and 24 J/cm(2). Each suspension was spread over the surface of a Petri plate before being incubated at 37°C, and counts of CFU were determined after 24 and 48 h.
  
  
  RESULTS
  Blue laser inhibited the growth of S. aureus and P. aeruginosa at fluences >6 J/cm(2). On the other hand, E. coli was inhibited at all fluences tested, except at 24 J/cm(2).
  
  
  CONCLUSIONS
  Blue laser light was capable of inhibiting bacterial growth at low fluences over time, thus presenting no time-dependent effect.
authors.affiliation: 1 Postgraduate Program in Rehabilitation and Functional Performance, Department of Biomechanics, Medicine, and Rehabilitation of the Locomotor Apparatus, Ribeirão Preto School of Medicine, University of São Paulo , Ribeirão Preto, SP, Brazil .
authors.forename: Natanael Teixeira Alves
authors.initials: NT
authors.lastname: de Sousa
authors.forename: Marcos Ferracioli
authors.initials: MF
authors.lastname: Santos
authors.forename: Rosana Caetano
authors.initials: RC
authors.lastname: Gomes
authors.forename: Hugo Evangelista
authors.initials: HE
authors.lastname: Brandino
authors.forename: Roberto
authors.initials: R
authors.lastname: Martinez
authors.forename: Rinaldo Roberto
authors.initials: RR
authors.lastname: de Jesus Guirro
mesh_terms: D004926:Escherichia coli / Q000528:radiation effects*; D054023:Lasers, Semiconductor; D028022:Low-Level Light Therapy; D011550:Pseudomonas aeruginosa / Q000528:radiation effects*; D013211:Staphylococcus aureus / Q000528:radiation effects*