Comparison of Antimicrobial Activity of Chitosan Nanoparticles Loaded with Amoxicillin with Free Amoxicillin against Some Gram Positive and Gram Negative Bacteria

Antibiotic resistance has prepared the way for substituting new therapeutic methods. Studies have indicated that nanoformulated antimicrobial agents have better therapeutic effects. In this study, the antimicrobial activity of chitosan nanoparticles loaded with amoxicillin (ACNs), was assessed in comparison with free amoxicillin against some Gram-positive and Gram-negative bacteria.
In this experimental study, the nanoparticles were prepared using the ionotropic gelation technique. The resulting nanoparticles were characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The antibacterial activity of amoxicillin and nanoparticles against standard and clinical strains of methicillin-susceptible and methicillin-resistant Staphylococcus aureus, Escherichia coli, and Enterococcus faecalis, was investigated by determination of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and inhibition zone diameters. Data were analyzed using one-way ANOVA with Tukeyʼs post hoc test.
The size of chitosan nanoparticles (CNs) and ACNs was 88 and 106 nm, respectively. ACNs showed higher antibacterial activity compared to amoxicillin and CNs without drug as determined by the smaller MIC (0.375mg/ml) and MBC (2 mg/ml) values and larger zones of inhibition (28mm). The highest and the lowest sensitivity to nanoparticles, were observed for Enterococcus feacalis and methicillin-resistant Staphylococcus aureus, respectively.
The results of this study showed that the nanoformulation of amoxicillin may be an appropriate strategy to increase its therapeutic effects. However, precise clinical studies are required for its confirmation