Evaluation of the Antimicrobial Effect of Ampicillin Encapsulated in Nano- Liposomes on Salmonella Typhimurium

In this study, the antimicrobial effect of the antibiotic ampicillin (AMP) is improved using nanotechnology-based drug delivery to achieve a more effective treatment. This study aims to evaluate the antimicrobial effect of both free AMP and its nano-liposomal encapsulated form on Salmonella Typhimurium ( S. Typhimurium ). Due to the widespread use of antibiotics in recent years, S. Typhimurium has developed antibiotic resistance. Therefore, this research investigates the potential of nano-liposomes as an effective solution against the antibiotic resistance of AMP. Nano-liposomes (NL) based on Phosphatidylcholine (PC) and cholesterol (CL) were initially prepared, and AMP (AMP) at a concentration of 1 mg/ml was encapsulated in these NLs. Minimal Inhibitory Concentrations (MICs) and Minimum Bactericidal Concentration (MBC) of the free and AMP-NL against AMP-resistant S . Typhimurium PTCC1730 and 4 clinical isolated strain of it were determined. The MIC of free AMP was 0.97 to 1.95 µg/mL, and for NL-AMP, it was 0.06 to 0.24 µg/mL. The MBC of free AMP ranged from 31.25 to 500 µg/mL, while that of NL-AMP was 3.90 to 125 µg/mL. Among the formulations, the NL with a 1:1 molar ratio of PC to C exhibited the smallest particle size and the highest encapsulation efficiency. MIC determination on S. Typhimurium isolates showed a significant decrease in MIC and MBC for nano-liposomal encapsulated AMP compared to its free form. It was found that the reduction in MIC and MBC of AMP against S . Typhimurium depended on the composition of the nano-liposomes.