Novel antibacterial peptide HfAMP against methicillin-resistant Staphylococcus aureus.

OBJECTIVES: The urgent development of novel antibacterial agents to combat antibiotic-resistant Staphylococcus aureus is imperative. Antimicrobial peptides are considered promising alternatives to traditional antibiotics for addressing this pressing issue. This study investigates the antibacterial activities and potential mechanisms of the peptide HfAMP against methicillin-resistant S. aureus (MRSA). METHODS: The antibacterial activity of HfAMP against MRSA was evaluated using the broth microdilution method, growth curve, and time-kill assay. Its potential mechanism of action was investigated through propidium iodide, laurdan, DiSC3(5), 2',7'-dichlorodihydrofluorescein diacetate, and ATP quantification assays. To assess the safety and stability of HfAMP, cytotoxicity, hemolysis, and antibacterial activity were examined under different conditions (i.e., temperatures, ions, serum, pH, and enzymes). Furthermore, a mouse skin infection model was employed to evaluate the in vivo efficacy of HfAMP. RESULTS: The results demonstrate that HfAMP exhibits bacteriostatic and bactericidal activity against MRSA, with a minimum inhibitory concentration of 4 µg/mL. It remains stable under a range of pH, temperatures, and serum, although it is susceptible to degradation by pepsin. Mechanistic investigations show that HfAMP compromises bacterial membranes by interacting with membrane components and disrupting the proton motive force, leading to metabolic disturbances. In a mouse model of MRSA-induced skin infection, HfAMP significantly reduced bacterial burden and inflammation in the affected skin tissues. CONCLUSION: Collectively, these findings indicate that HfAMP possesses potent antibacterial activity against MRSA by compromising bacterial viability and inhibiting virulence, highlighting its potential as a promising candidate for the treatment of MRSA skin-infection.