Antimicrobial effect of plant peptide MBP-1 and silver nanoparticles, along with their synergistic effect on skin infection due to Pseudomonas aeruginosa: in vitro and animal model

Pseudomonas aeruginosa is an opportunistic pathogen with innate resistance to many antibiotics and disinfectants that cause severe، acute and chronic nosocomial infections in immunocompromised، catheterized or burn patients. MBP-1 is a plant antimicrobial peptide that has showed antimicrobial activity against some bacteria and filamentous fungi. The antimicrobial effect of silver nanoparticles against a range of microorganisms have also been reported. The aim of the present study was to investigate the synergistic effect of MBP-1 and silver nanoparticles combination against skin infection caused by Pseudomonas aeruginosa. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of MBP_1، silver nanoparticles and their combination was measured based on the microdilution and macrodilution susceptibility test. The synergistic effect of MBP-1 and silver nanoparticles combination was investigated using 12 mice with induced bacterial skin infection using Pseudomonas aeruginosa. The results showed that MIC and MBC of silver nanoparticles for P. aeruginosa were 3. 12 and 6. 25 ppm، respectively. The MIC and MBC of plant peptide MBP-1 were 500 and 600 µg/ml، respectively. MIC and MBC of MBP-1 and silver nanoparticles combination on P. aeruginosa were 400 µg/ml، 1. 56 ppm and 500 µg/ml، 3. 125 ppm، respectively. Therefore، antimicrobial effect of MBP-1، silver nanoparticles and their combination against skin infections due to P. aeruginosa was approved in mouse model. The results showed that MBP_1 and silver nanoparticles have antimicrobial effect against P. aeruginosa and their combination has synergistic effect to heal skin infection caused by P. aeruginosa in mouse model.