title: Dalbavancin reduces biofilms of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE).
abstract: Activity of dalbavancin against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) in biofilm was investigated and the microbicidal biofilm concentrations (MBC) were determined. Biofilms obtained from ten MRSA and ten MRSE bloodstream isolates, collected from patients in the General Hospital of Vienna between 2012 and 2015, were incubated with dalbavancin in trypticase soy broth (TSB) in serial dilution from 0.0625 mg/l to 256 mg/l using a microtiter plate biofilm model. The plates were incubated for 24 h at 37 ° C and 50% humidity. Biofilms were fixed with 2.5% glutaraldehyde and stained with crystal violet. Subsequently the optical density (OD620) was used to measure the MBC, defined as the concentration of dalbavancin leading to a 50% reduction of biofilm. MBC for MRSA was 1 mg/l-4 mg/l (minimal inhibitory concentrations (MIC) 0.0312 mg/l-0.064 mg/l). MBC for MRSE was 2 mg/l-16 mg/l (MIC 0.023 mg/l-0.0625 mg/l). Dalbavancin successfully reduced MRSA and MRSE in biofilms, and therefore provides a promising option for the treatment of biofilm-associated infections.
authors.affiliation: Division of Infectious Diseases and Tropical Medicine, Department of Medicine I, Medical University Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria. daniela.knafl@meduniwien.ac.at.
authors.forename: D
authors.initials: D
authors.lastname: Knafl
authors.affiliation: Division of Infectious Diseases and Tropical Medicine, Department of Medicine I, Medical University Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Tobudic
authors.affiliation: Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.
authors.forename: S C
authors.initials: SC
authors.lastname: Cheng
authors.affiliation: Dunedin School of Medicine, University of Otago, Wellington, New Zealand.
authors.forename: D R
authors.initials: DR
authors.lastname: Bellamy
authors.affiliation: Division of Infectious Diseases and Tropical Medicine, Department of Medicine I, Medical University Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors.forename: F
authors.initials: F
authors.lastname: Thalhammer
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001317:Austria; D016470:Bacteremia / Q000382:microbiology; D018441:Biofilms / Q000187:drug effects*; D003124:Colorimetry; D005840:Gentian Violet / Q000032:analysis; D006769:Hospitals, General; D006801:Humans; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D013194:Staining and Labeling; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000502:physiology; D013212:Staphylococcus epidermidis / Q000187:drug effects* / Q000502:physiology; D017334:Teicoplanin / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D017334:Teicoplanin; C469289:dalbavancin; D005840:Gentian Violet