Study the Effect of Conjugate Novel Ultra-Short Antimicrobial Peptide with Silver Nanoparticles against Methicillin Resistant S. aureus and ESBL E. coli .

Background: Bacterial resistance is a challenging limitation in infection treatment. This work evaluates the potential antibacterial activity of conjugation of Tryasine peptide with silver nanoparticles against selected pathogens. Materials and Methods: The peptide Tryasine was produced using three subunits of tryptophan and three lysine amino acids, then its purity was determined by reverse-phase high-performance liquid chromatography. The peptide was confirmed using mass spectrometry and electrospray ionization mass spectrometry. Silver nanoparticles conjugate with Tryasine was synthesized by adding Tryasine-silver nitrate solution in the presence of the reducing agent sodium borohydride. The presence of Tryasine-silver nanoparticles was indicated by the yellow-brown color and was further confirmed through ultraviolet-visible spectrophotometry. The minimum inhibitory and minimum bactericidal concentrations for Tryasine nanoparticles were determined against Staphylococcus aureus , Escherichia coli , methicillin resistant Staphylococcus aureus , and ESBL Escherichia coli using the microdilution method. Toxicity for nanoparticles conjugated with Tryasine was determined using erythrocyte hemolytic assay. Results: Tryasine alone was effective (MIC around 100 and 200 μM) against standard and resistant strains of bacteria used. However, Tryasine-silver nanoparticles were more effective with MICs ranging from 30 to 100 μM depending on the bacterial strain used. Tryasine-silver nanoparticles at concentration of 100 μM only caused 1% hemolysis on human erythrocytes after 30 min of incubation. Conclusions: The findings indicate that Tryasine-silver nanoparticles had good antibacterial activity against pathogenic strains of Gram-positive and Gram-negative bacteria. Additionally, the conjugate showed low hemolytic activity and cytotoxicity. Therefore, conjugation of Tryasine with silver nanoparticles is a promising treatment candidate for bacterial infection with low toxicity.