Bactericidal effect of gentamicin-induced membrane vesicles derived from Pseudomonas aeruginosa PAO1 on gram-positive...

Area of Science:

• Microbiology
• Bacteriology
• Drug Delivery Systems

Background:

• Pseudomonas aeruginosa PAO1 produces gentamicin-induced membrane vesicles (g-MVs).
• g-MVs contain both the antibiotic gentamicin and a potent peptidoglycan hydrolase (PGase; autolysin).
• g-MVs have previously shown efficacy against gram-negative pathogens.

Purpose of the Study:

• To evaluate the therapeutic potential of g-MVs against four gram-positive bacteria.
• To compare the efficacy of g-MVs with soluble gentamicin.
• To investigate the mechanism of g-MV interaction with gram-positive bacterial cell surfaces.

Main Methods:

• Bactericidal assays were performed against Bacillus subtilis, Staphylococcus aureus, Listeria monocytogenes, and Enterococcus hirae.
• Electron microscopy was used to examine thin sections of bacteria treated with g-MVs.
• Hydrophobic interaction chromatography and zymograms were employed to analyze MV attachment and autolysin activity.

Main Results:

• Bacillus subtilis and Staphylococcus aureus were susceptible to g-MV killing, while Listeria monocytogenes showed slight susceptibility, and Enterococcus hirae was unaffected.
• g-MVs were generally more effective than soluble gentamicin.
• MV attachment varied based on bacterial surface hydrophobicity, and autolysin activity was observed in most tested organisms except E. hirae.

Conclusions:

• g-MVs exhibit selective bactericidal activity against certain gram-positive bacteria.
• The dual action of gentamicin and autolysin contributes to g-MV efficacy.
• g-MVs represent a promising therapeutic strategy for specific gram-positive bacterial infections, warranting further investigation.