Characterization and antibacterial action mode of bacteriocin BMP32r and its application as antimicrobial agent for the therapy of multidrug-resistant bacterial infection

Multidrug-resistant (MDR) bacterial infection still poses a serious threat to public health, therefore, effective and safe antimicrobial agents are urgently needed. In this study, recombinant bacteriocin BMP32 (BMP32r) prepared by the Escherichia coli expression system had a broad-spectrum antibacterial activity even against some MDR bacteria and its minimum inhibitory concentration ranged from 9.2 to 36.8 mg/L. Furthermore, BMP32r showed good stable performance in heat, pH and storage. Moreover, the scanning electron microscope and transmission electron microscope revealed that BMP32r killed indicator strains through cell wall destruction, pore formation, and the membrane permeability increasing which was proved by propidium iodide uptake investigation. The wound healing of an animal MDR S. aureus infected model was promoted by BMP32r, and the safety was verified by the cytotoxicity assay that the viability of HFF cells remained 87.3% in even when the concentration of BMP32r was as high as 147.2 mg/L. In addition, no abnormalities or damages to major organs was found in vivo assessments after treatment with BMP32r. In conclusion, BMP32r has great potential to be developed as a safe antimicrobial agent to treat MDR bacterial infections.