A novel peptide oyster-derived antimicrobial peptide against clinical carbapenem-resistant Acinetobacter baumannii

Background The escalating prevalence of multidrug-resistant pathogens, specifically carbapenem-resistant Acinetobacter baumannii (CR-AB), underscores the urgent need for novel antimicrobial strategies. Antimicrobial peptides (AMPs) offer a viable alternative to conventional antibiotics. Methods We discovered a novel AMP, designated OAMP, from oyster hemolymph and evaluated its antimicrobial efficacy against a spectrum of pathogens, including five clinical CR-AB strains. The synergistic potential of OAMP with meropenem, tigecycline, and colistin was assessed via checkerboard assays. Safety profiles were determined through cytotoxicity and hemolysis assays. Results OAMP exhibited potent broad-spectrum activity, effectively inhibiting CR-AB strains with MIC values of 4–8 µM. In combination therapies, OAMP demonstrated additive to synergistic effects with conventional antibiotics, facilitating a reduction in antibiotic dosage. However, safety assessments revealed cytotoxicity and hemolytic activity at MIC levels, indicating a narrow therapeutic window. Conclusions OAMP shows significant promise as a potent antibacterial agent and an effective adjuvant for combinatorial therapy against CR-AB. Future studies should focus on structural optimization to mitigate toxicity and enhance stability for clinical application.