Peptide P2.2, a non-ribosomal antimicrobial peptide, exhibits potent antibacterial activity, with an MIC50 of 4 μM against V. parahaemolyticus and 32 μM against V. alginolyticus. This peptide enhances the synergistic antimicrobial effects when used in conjunction with antibiotics (e.g., Ofloxacin and Linezolid) and shows negligible hemolytic activity. Peptide P2.2 disrupts bacterial membranes and increases their permeability by modulating proteins involved in the type VI and type III secretion systems. It is applicable in bacterial infection research.