Antimicrobial photodynamic therapy —a promising treatment for prosthetic joint infections

This study investigated Photodynamic Therapy (PDT) as a means of eradicating bacteria that cause PJI, using a laser with a 665-nm wavelength and methylene blue (MB) as the photosensitizer. The effectiveness of MB concentration on the growth inhibition of methicillin-sensitiveStaphylococcus aureus (MSSA), methicillin-resistantStaphylococcus aureus (MRSA),Staphylococcus epidermidis,Pseudomonas aeruginosa andAcinetobacter baumannii was investigated. The effect of laser dose was also investigated and the optimized PDT method was used to investigate its bactericidal effect on species within planktonic culture and following the formation of a biofilm on polished titanium and hydroxyapatite coated titanium discs. Results showed that Staphylococci were eradicated at the lowest concentration of 0.1  mM methylene blue (MB). WithP. aeruginosa andA. baumannii, increasing the MB concentration improved the bactericidal effect. When the laser dose was increased, results showed that the higher the power of the laser the more bacteria were eradicated with a laser power  ≥ 35 J/cm2 and an irradiance of 35  mW/cm2, eradicating allS. epidermidis. The optimized PDT method had a significant bactericidal effect against planktonic MRSA andS. epidermidis compared to MB alone, laser alone, or control (no treatment). When biofilms were formed, PDT treatment had a significantly higher bactericidal effect than MB alone and laser alone for all species of bacteria investigated on the polished disc...
Source: Lasers in Medical Science - Category: Laser Surgery Source Type: research