Time-Kill Kinetic of Chitosan-Coated Ferrous Sulfate Loaded Nanoliposome Against E. coli and S. aureus

The nanoliposomes containing ferrous sulfate were produced by thin-layer hydration, sonication, and coated with nano-chitosan. Chitosan coating (0.2% w/v) and various lecithin: ferrous sulfate ratios (5:1, 10:1, and 20:1 w/w) were characterized based on the antimicrobial properties. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ferrous sulfate against Escherichia coli ATCC 2592 and Staphylococcus aureus ATCC 25923 were 1000 and 1500 mg/mL, respectively. The incorporation of ferrous sulfate into the nanoliposomes lowered its MIC and MBC values. The optical density (OD₆₀₀) of E. coli (0.516) and S. aureus (0.738) in the control culture exposed to free ferrous sulfate and ferrous sulfate loaded nanoliposomes with different levels of lecithin to ferrous sulfate (5:1, 10:1, and 20:1 w/w) at MIC values decreased around 12.04% and 22.19%, 16.55% and 35.56%, 25.57% and 35.56%, 51.78% and 63.59%, respectively. Exposure of E. coli and S. aureus to free ferrous sulfate and ferrous sulfate loaded nanoliposomes decreased AUC and increased the lag phase of both bacteria (p < 0.05). A significant reduction was observed in the optical density and AUC of the E. coli and S. aureus cultures exposed to chitosan-coated nanoliposomes containing ferrous sulfate. The highest percentage reduction in final optical density and the lowest AUC of E. coli and S. aureus cultures were observed after being exposed to chitosan-coated nanoliposomes prepared at lecithin: ferrous sulfate ratio of 20:1 (w/w).