Antibacterial activity against Gram-positive bacteria using fusidic acid-loaded lipid-core nanocapsules

Abstract

We proposed the development of fusidic acid-loaded lipid-core nanocapsules to improve the in vitro antibacterial activity of the drug against Staphylococcus aureus, Enterococcus faecalis and Staphylococcus epidermidis strains. The effect of the particle mean diameter and zeta potential on the bacterial behavior, as well as the nanocapsule interactions with bacteria by infra-red spectroscopy were determined. The nanoencapsulation of FA, in lipid-core nanocapsules coated or not with chitosan, modified the biological behavior of the drug and provided better in vitro performance against S. aureus, E. faecalis and S. epidermidis strains. The nanocapsules-bacteria interactions were evaluated by mean diameter, polydispersity index, and zeta potential. Aggregates were formed after contact of the formulations with S. aureus, E. faecalis and S. epidermidis, which results were confirmed by infrared spectra showing a peak at 1651 cm−1 attributed to the stretching mode of CO, amide I, or stretching mode (C=O) of COO− group (S. aureus), a peak at 1653 cm−1 related to the stretching mode of COO− group, another at 1149 cm−1 associated to C-O-C-ester bonds (E. faecalis), and at 1626 cm−1 the stretching mode CO (amide I) likely related to carboxylic groups (S. epidermidis). Our study, backed by in vitro evidences, offers preliminary data and a ray of hope for the development of a candidate product for the treatment of infections caused by Gram-positive bacteria.