Formulation Optimization of Chitosan-Stabilized Silver Nanoparticles Using In Vitro Antimicrobial Assay

Antimicrobial resistance at the infected site is a serious medical issue that increases patient morbidity and mortality. Silver has antibacterial activity associated with some dose-dependent toxicity. Silver nanoparticles, due to larger surface area, have antibacterial properties, which make them useful in the treatment of infections. Chitosan-stabilized silver nanoparticles (CH-AgNP) were formulated and evaluated for minimal inhibitory concentration and minimal bactericidal concentration testing against Staphylococcus aureus ATCC 29213, S aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, and 20 methicillin-resistant S aureus isolates. Minimum biofilm eradication concentration study was used to evaluate the biofilm reduction, and in vitro antimicrobial checkerboard assays were performed. The effective optimum ratio of AgNP:chitosan solution was 1:4. Minimal inhibitory concentration and minimal bactericidal concentration ranges of CH-AgNP were 4 to 14 times lower compared to AgNP alone against methicillin-resistant S aureus isolates. Minimum biofilm eradication concentration values of CH-AgNP for ATCC PA-01, P aeruginosa isolate 1, and P aeruginosa isolate 2 were found to be >84.59 μg/mL, 42.29 μg/mL, and 21.15 μg/mL, respectively. Thus, CH-AgNP is a potential formulation for wound treatment and management of infected sites associated with antimicrobial resistance.