title: In vitro activity of daptomycin and vancomycin lock solutions on staphylococcal biofilms in a central venous catheter model.
abstract: BACKGROUND
  Catheter lock solutions are used for prevention and management of catheter-related bloodstream infections. We investigated the activity of daptomycin and vancomycin lock solutions against Staphylococcus aureus and Staphylococcus epidermidis in an in vitro central venous catheter (CVC) model.
  
  
  METHODS
  Biofilm-producing reference strains of S. aureus and S. epidermidis were evaluated. After 24 h of bacterial growth in a CVC model, daptomycin and vancomycin bactericidal activity (+/- preservative-containing heparin sodium) were separately evaluated as a lock solution using 0.5, 1 and 35 mg/ml. Calcium carbonate (50 mg/l) was added to all lock solutions containing daptomycin. Each CVC was drained, flushed and sonicated at 72 h to assess CFU/ml.
  
  
  RESULTS
  After 72 h of exposure in the catheter lock solutions, daptomycin and vancomycin at 0.5, 1 and 5 mg/ml demonstrated bactericidal activity (>3.0 log10 CFU/ml) against S. aureus and S. epidermidis (P <or= 0.001). Heparin lock solution alone produced a non-significant reduction in S. aureus and S. epidermidis (1.92 +/- 0.07 and 1.65 +/- 0.03 log10 CFU/ml, respectively). Daptomycin 5 mg/ml lock solution +/- heparin eradicated (limit of detection 2.0 log10 CFU/ml) S. epidermidis at 72 h as did the vancomycin 5 mg/ml plus heparin. S. aureus was only eradicated from the daptomycin 5 mg/ml catheter lock-solution.
  
  
  CONCLUSIONS
  Our CVC model demonstrated that 72 h of exposure to 5 mg/ml lock solutions of daptomycin (plus calcium), +/- heparin or 5 mg/ml of vancomycin plus heparin demonstrate promise in treating catheter infections with biofilm-producing S. epidermidis. Similarly, 5 mg/ml of daptomycin (plus calcium) as a lock solution shows great promise in treating S. aureus catheter infections.
authors.affiliation: Department of Pharmacy Practice, University of Rhode Island, Kingston, RI 02881, USA. KerryTedesco@uri.edu
authors.forename: Kerry L
authors.initials: KL
authors.lastname: LaPlante
authors.forename: Leonard A
authors.initials: LA
authors.lastname: Mermel
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D018441:Biofilms; D002119:Calcium Carbonate / Q000494:pharmacology; D002405:Catheterization, Central Venous / Q000295:instrumentation*; D017576:Daptomycin / Q000494:pharmacology*; D004866:Equipment Contamination; D004868:Equipment Failure; D012016:Reference Values; D013211:Staphylococcus aureus / Q000378:metabolism; D013212:Staphylococcus epidermidis / Q000378:metabolism; D013242:Sterilization; D013997:Time Factors; D014640:Vancomycin / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin; D002119:Calcium Carbonate; D017576:Daptomycin