Synergistic Photodynamic Therapy with Metalloporphyrins and Gentamicin Against MRSA

The rise of antibiotic resistance in pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) necessitates novel therapeutic approaches. Photodynamic antimicrobial chemotherapy (PACT), in combination with antibiotics, offers an effective alternative by generating reactive oxygen species that target microbial cells, minimizing the development of resistance. This study investigated the antibacterial efficacy of four porphyrin-based photosensitizers (P-2H, P-Zn, P-InCl, and P-GaCl) against MRSA, both independently and in synergy with gentamicin. Spectroscopic characterization and photophysical analyses were performed, followed by antimicrobial assays under light irradiation at 430 nm. PACT significantly enhanced bacterial inactivation, with P-InCl exhibiting the least ΦF (0.0002) and the ϕΔ (0.52). The combination of PACT and gentamicin demonstrated a synergistic effect, reducing bacterial viability more than individual treatments. These findings highlight the potential of metallated porphyrins in combination with antibiotics as a promising strategy to combat Methicillin-resistant Staphylococcus aureus (MRSA) infections, warranting further preclinical studies.