Antimicrobial photodynamic therapy against multidrug-resistant Staphylococcus aureus using aluminum chloride phthalocyanine nanoemulsion: in vitro and in vivo studies.

Antimicrobial photodynamic therapy is a promising approach for treating superficial infections caused by resistant strains. This study evaluated the effectiveness of antimicrobial photodynamic therapy against multidrug-resistant Staphylococcus aureus using aluminum chloride phthalocyanine encapsulated in nanoemulsion (NE/ClAlPc) in a rat burn wound model under in vitro and in vivo conditions. In vitro, NE/ClAlPc-mediated antimicrobial photodynamic therapy was assessed for bacterial logarithmic reduction, inhibition of biofilm metabolism, and cytotoxicity on mouse skin fibroblasts (L929) using the MTT assay at 6, 12, and 24 h. Cell migration was evaluated via the scratch wound assay. In vivo, seven groups of male rats with burn wounds were treated with antimicrobial photodynamic therapy. Wound areas were measured, and skin biopsies were analyzed for histological changes and mRNA expression levels of FGF1, TGF-β1, and GPX1 genes using real-time PCR. Results showed an 8-log10 reduction in the survival of multidrug-resistant S. aureus and a 60% reduction in biofilm metabolism. NE/ClAlPc-mediated antimicrobial photodynamic therapy inhibited bacterial growth, stimulated fibroblast migration, and accelerated wound healing. Histological analysis confirmed reduced wound areas and faster healing. Real-time PCR exposed strong GPX1 mRNA expression post-injury, elevated FGF1 mRNA in untreated wounds, and increased TGF-β1 mRNA after laser treatment. NE/ClAlPc-mediated antimicrobial photodynamic therapy demonstrated potent antibacterial and antibiofilm activity against multidrug-resistant S. aureus, significantly reducing burn wound areas and promoting healing in rats. This treatment shows promise as an alternative for eradicating multidrug-resistant bacteria.