title: Activity of daptomycin- and vancomycin-loaded poly-epsilon-caprolactone microparticles against mature staphylococcal biofilms.
abstract: The aim of the present study was to develop novel daptomycin-loaded poly-epsilon-caprolactone (PCL) microparticles with enhanced antibiofilm activity against mature biofilms of clinically relevant bacteria, methicillin-resistant Staphylococcus aureus (MRSA) and polysaccharide intercellular adhesin-positive Staphylococcus epidermidis. Daptomycin was encapsulated into PCL microparticles by a double emulsion-solvent evaporation method. For comparison purposes, formulations containing vancomycin were also prepared. Particle morphology, size distribution, encapsulation efficiency, surface charge, thermal behavior, and in vitro release were assessed. All formulations exhibited a spherical morphology, micrometer size, and negative surface charge. From a very early time stage, the released concentrations of daptomycin and vancomycin were higher than the minimal inhibitory concentration and continued so up to 72 hours. Daptomycin presented a sustained release profile with increasing concentrations of the drug being released up to 72 hours, whereas the release of vancomycin stabilized at 24 hours. The antibacterial activity of the microparticles was assessed by isothermal microcalorimetry against planktonic and sessile MRSA and S. epidermidis. Regarding planktonic bacteria, daptomycin-loaded PCL microparticles presented the highest antibacterial activity against both strains. Isothermal microcalorimetry also revealed that lower concentrations of daptomycin-loaded microparticles were required to completely inhibit the recovery of mature MRSA and S. epidermidis biofilms. Further characterization of the effect of daptomycin-loaded PCL microparticles on mature biofilms was performed by fluorescence in situ hybridization. Fluorescence in situ hybridization showed an important reduction in MRSA biofilm, whereas S. epidermidis biofilms, although inhibited, were not eradicated. In addition, an important attachment of the microparticles to MRSA and S. epidermidis biofilms was observed. Finally, all formulations proved to be biocompatible with both ISO compliant L929 fibroblasts and human MG63 osteoblast-like cells.
authors.affiliation: Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal.
authors.forename: Inês Santos
authors.initials: IS
authors.lastname: Ferreira
authors.affiliation: Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal.
authors.forename: Ana F
authors.initials: AF
authors.lastname: Bettencourt
authors.affiliation: Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal.
authors.forename: Lídia M D
authors.initials: LM
authors.lastname: Gonçalves
authors.affiliation: Biofilmcenter, German Heart Institute Berlin, Berlin, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Kasper
authors.affiliation: Infectious Diseases Service, Department of Medicine, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Bétrisey
authors.affiliation: Biofilmcenter, German Heart Institute Berlin, Berlin, Germany.
authors.forename: Judith
authors.initials: J
authors.lastname: Kikhney
authors.affiliation: Biofilmcenter, German Heart Institute Berlin, Berlin, Germany.
authors.forename: Annette
authors.initials: A
authors.lastname: Moter
authors.affiliation: Center for Musculoskeletal Surgery, Charité - University Medicine Berlin, Berlin, Germany.
authors.forename: Andrej
authors.initials: A
authors.lastname: Trampuz
authors.affiliation: Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal.
authors.forename: António J
authors.initials: AJ
authors.lastname: Almeida
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects*; D002208:Caproates / Q000737:chemistry*; D017576:Daptomycin / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D007783:Lactones / Q000737:chemistry*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D008863:Microspheres; D014640:Vancomycin / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D002208:Caproates; D007783:Lactones; C121056:caprolactone; D014640:Vancomycin; D017576:Daptomycin
keywords: Staphylococcus aureus; Staphylococcus epidermidis; antibiotic release; fluorescence in situ hybridization; isothermal microcalorimetry