Pepholin, a bacteriophage holin-derived peptide, eradicates MDR P. aeruginosa in burn wounds

Multidrug-resistant (MDR) Pseudomonas aeruginosa poses a critical threat to burn wound healing, as conventional antibiotics are increasingly ineffective. This necessitates novel therapeutic strategies to combat these persistent infections. Antimicrobial peptides (AMPs) offer a promising alternative, but new scaffolds are needed. Bacteriophage holins, proteins that disrupt bacterial membranes, represent an underexplored source for designing potent AMPs. This study investigates a holin-derived peptide to address the urgent need for effective anti-MDR agents.

Researchers used an AI-guided strategy to design Pepholin, a 12-amino acid antimicrobial peptide derived from a Pseudomonas bacteriophage holin. In vitro, they assessed its antibacterial and antibiofilm activities against MDR P. aeruginosa, membrane disruption via permeabilization assays, hemocompatibility, and mammalian cell cytotoxicity. For in vivo evaluation, Pepholin was formulated into a carbomer-based hydrogel and applied topically to a murine burn wound infection model challenged with MDR P. aeruginosa. Primary endpoints included bacterial clearance, wound healing rates, collagen deposition, and modulation of cytokine responses.

Mechanistic studies confirmed its bactericidal action by permeabilizing and disrupting bacterial membranes in a concentration and time-dependent manner. The peptide exhibited high hemocompatibility and minimal cytotoxicity in mammalian cells, with selectivity indices greater than 8. Crucially, Pepholin maintained its antibacterial efficacy under physiological conditions, including high salt, serum, and body temperature. In the murine burn wound infection model, topical treatment with the Pepholin hydrogel significantly enhanced bacterial clearance from the wounds. Furthermore, it accelerated the overall wound healing process, promoted robust collagen deposition, and favorably modulated local cytokine responses, indicating a comprehensive therapeutic effect beyond just bacterial killing.