Native Pig Neutrophil Products: Insights into Their Antimicrobial Activity

Area of Science:

• Antimicrobial Peptides
• Molecular Biology
• Microbiology

Background:

• Cationic antimicrobial peptides (AMPs) possess antimicrobial and immunomodulatory properties.
• Porcine neutrophil cathelicidin mixture (MPPN) is explored for its therapeutic potential.
• Understanding AMP mechanisms is crucial for combating infections and antimicrobial resistance.

Purpose of the Study:

• To investigate the antimicrobial activity and mechanisms of action of MPPN.
• To evaluate MPPN's effects on bacterial growth, membrane integrity, and efflux pump activity.
• To assess MPPN's potential in addressing antimicrobial resistance.

Main Methods:

• Minimum inhibitory concentration (MIC) determination, time-kill kinetics, and growth curve analysis.
• Planar black lipid bilayer conductance assays to study membrane interactions.
• Atomic force microscopy (AFM), transmission electron microscopy (TEM), and acridine orange (AO) assay for bacterial surface and efflux pump analysis.

Main Results:

• MPPN exhibited bactericidal activity against E. coli at high concentrations and bacteriostatic effects at lower concentrations.
• Bacteriostatic effects were also observed in S. enterica; MPPN was inactive against S. aureus.
• MPPN inhibited efflux pump function in E. coli, altered lipid bilayers, and damaged bacterial surfaces.

Conclusions:

• MPPN demonstrates significant antimicrobial activity against Gram-negative bacteria by disrupting membranes and inhibiting efflux pumps.
• The ability of MPPN to inhibit efflux pumps presents a promising strategy for combating antimicrobial resistance.
• MPPN could be a valuable agent, used alone or in combination with conventional antibiotics, to overcome resistance mechanisms.