In vitro activity of daptomycin and vancomycin lock solutions on staphylococcal biofilms in a central venous catheter model.

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
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.