In Vitro Antimicrobial Effect of Encapsulated Vancomycin on Internalized Staphylococcus aureus Within Endothelial Cells

ABSTRACT Vancomycin (VCN) is a glycopeptide antibiotic that is effective in the treatment of gram-positive bacterial infections, but mainly reserved for methicilin resistant Staphylococcus aureus. It is, however, ineffective against intracellular bacteria and hence a particulate form of VCN would be required. Bovine serum albumin (BSA) microspheres of VCN with a mean particle size of 5 ± 1.6 μm were used. Human microvascular endothelial cells internalized both S. aureus and VCN microspheres in a time and concentration-dependent manner, however, the uptake was inhibited by cytochalasin D. Action of VCN on S. aureus in the intracellular microenvironment decreased the bacterial load considerably.