Abstract

Antibiotic resistance poses a significant and growing global health threat, driven by the overuse and misuse of antibiotics in human medicine and agriculture. This resistance results in reduced efficacy of conventional therapies and increased morbidity, mortality, and healthcare costs. Current trends show a rapid rise in multidrug-resistant bacteria, including problematic Gram negative species, complicating treatment options. Mechanisms underlying antibiotic resistance include enzymatic drug degradation, target modifications, efflux pump overexpression, and biofilm formation, which collectively limit antibiotic penetration and efficacy. As conventional antibiotics become less effective, innovative therapeutic alternatives are urgently needed. Photodynamic therapy (PDT) has emerged as a promising non-antibiotic approach to combat resistant infections. PDT involves the administration of a photosensitizer coupled with visible light illumination, generating reactive oxygen species that cause localized microbial cell damage. This approach has a broad-spectrum effect and reduces the likelihood of resistance development due to its multimodal mechanism. A particular focus is placed on RLP068/Cl, a chlorin-based photosensitizer showing potent antimicrobial photodynamic activity. RLP068/Cl effectively targets resistant pathogens and biofilms while promoting wound healing. Its activation with red light provides tissue penetration suitable for treating skin and soft tissue infections. Recent preclinical and clinical data highlight RLP068/Cl’s safety and efficacy as an adjunct or alternative to antibiotics, especially against multidrug-resistant bacteria. This presentation will review antibiotic resistance trends and mechanisms, discuss current counter measures, and explore the clinical potential of PDT with emphasis on RLP068/Cl, outlining its role in future infection management strategies.