Evaluation of antimicrobial photodynamic therapy on wounds infected by Staphylococcus aureus in animal models

Background: Antibiotic-resistant Staphylococcus aureus bacteria are one of the expanding challenges. The purpose of current study is to evaluate the antimicrobial effect of photodynamic therapy (aPDT) on wounds infected to Staphylococcus aureus.

Methods: In this study, 40 six-month-old rats were divided into 4 groups: control, photosensitizer (PS), laser, and aPDT. A full-thickness wound was created on their skin and it was infected by Staphylococcus aureus. For aPDT, the Indocyanine Green (Germany, Nürnberg, A.R.C. Laser, EmunDo) photosensitive agent and laser diod 810 nm (Germany, Nürnberg, A.R.C. Laser) was utilized. The wound healing procedure was monitored every 24 h until the 12th day with photography. The number of the bacteria was counted on the 12th day also. All results were compared using ANOVA and Tukey post hoc tests. Significance level was considered P-Value < 0.05.

Results: The average area of wound reduced in days 5-11th in photosensitizer, laser, and aPDT, respectively. The absolute colonization rate of bacteria in the wounds showed a significant decrease in two groups laser and aPDT compared to the control group. However, the lowest value was for the aPDT.

Conclusion: In the conditions of this study, it emerged that aPDT and laser have an antimicrobial effect against antibiotic-resistant bacteria (particularly Staphylococcus aureus) and improve wound healing.