Antimicrobial Photodynamic Therapy on Pseudomonas aeruginosa Using a Diode Laser and PhotoMed, Methyl Pheophorbide A, or RadachlorinⓇ

Abstract

Photodynamic therapy (PDT) activates intracellular oxygen using a photosensitizer activated by light of a specific wavelength and is a potential means of treating wound infections caused by antibiotic-resistant bacteria. Pseudomonas aeruginosa (P. aeruginosa) is typically non-pathogenic in healthy individuals but can induce severe illnesses like sepsis in the immunocompromised. Antibiotics have been conventionally used to treat P. aeruginosa infections, but increasing antibiotic resistance caused by drug misuse poses a growing challenge to the management of these infections. This study aimed to investigate the ability of PDT using photosensitizers (PhotoMed, Methyl pheophorbide A, or RadachlorinⓇ) and a diode laser to inhibit P. aeruginosa. Suspensions of P. aeruginosa and a photosensitizer were inoculated into Petri dishes and incubated for 30 minutes. Samples were then irradiated with the laser at 3 J/cm2, and after incubation, colony areas were measured. P. aeruginosa killing rates were 79.65% for PhotoMed, 47.36% for Methyl pheophorbide A, and 40.91% for RadachlorinⓇ. This study shows that PDT using a diode laser and a photosensitizer constitutes an effective practical therapeutic approach for inhibiting P. aeruginosa.

Keywords

• methyl pheophorbide a
• photodynamic therapy
• photomed
• radachlorinⓡ
• pseudomonas aeruginosa