Time-dependent antimicrobial effect of photodynamic therapy with TONS 504 on Pseudomonas aeruginosa

• Published in: Lasers in medical science 2018-09, Vol.33 (7), p.1455-1460
• Main Authors: Sueoka, Kentaro, Chikama, Taiichiro, Latief, Miftahul Akhyar, Ko, Ji-Ae, Kiuchi, Yoshiaki, Sakaguchi, Takemasa, Obana, Akira
• Format: Article
• Language: English
• Subjects: Anti-Infective Agents - pharmacology; Antiinfectives and antibacterials; Antimicrobial agents; Bacteria; Blindness; Chemotherapy; Colonies; Colony-Forming Units Assay; Dentistry; Exposure; Humans; Infectious diseases; Irradiation; Keratitis; Lasers; Light emitting diodes; Medicine; Medicine & Public Health; Optical Devices; Optics; Original Article; Pathogens; Photochemotherapy; Photodynamic therapy; Photonics; Photosensitizing Agents - chemistry; Photosensitizing Agents - pharmacology; Porphyrins - pharmacology; Pseudomonas aeruginosa; Pseudomonas aeruginosa - drug effects; Quantum Optics; Time dependence; Time Factors; Viability
• ISSN: 0268-8921; 1435-604X
• DOI: 10.1007/s10103-018-2490-0

Pseudomonas aeruginosa ( P. aeruginosa ) is a major cause of infectious keratitis, which itself is a major cause of blindness worldwide. We have now evaluated the time-dependent effectiveness of photodynamic antimicrobial chemotherapy (PACT) with the chlorin derivative TONS 504 and a light-emitting diode (LED) on P. aeruginosa in vitro. PACT with TONS 504 (10 mg/L) and irradiation (30 J/m 2 ) by an LED device that delivers light centered on a wavelength of 660 nm was applied to 1 × 10 6 colony-forming units of P. aeruginosa in liquid medium. The bacteria were then cultured at 37 °C for various times before assay of viability by determination of colony formation on agar plates. The effect of a second irradiation at 3 h after the initial LED exposure was also examined. Bacterial growth was markedly inhibited between 3 and 9 h after PACT with TONS 504, with the maximal effect being apparent at 3 h. Furthermore, a second exposure to LED irradiation at 3 h after the first treatment enhanced the inhibitory effect on bacterial growth. PACT with TONS 504 thus inhibited the growth of P. aeruginosa in a time-dependent manner, and an additional irradiation exposure applied 3 h after the first LED treatment greatly increased the effectiveness of PACT. This antibacterial system thus warrants further evaluation with regard to its potential effectiveness for the treatment of infectious keratitis.