Efficacy of daptomycin versus vancomycin in an experimental model of foreign-body and systemic infection caused by biofilm producers and methicillin-resistant Staphylococcus epidermidis

Antimicrob Agents Chemother. 2012 Feb;56(2):613-7. doi: 10.1128/AAC.05606-11. Epub 2011 Nov 28.

Abstract

Staphylococcus epidermidis is a frequent cause of device-associated infections. In this study, we compared the efficacy of daptomycin versus vancomycin against biofilm-producing methicillin-resistant S. epidermidis (MRSE) strains in a murine model of foreign-body and systemic infection. Two bacteremic biofilm-producing MRSE strains were used (SE284 and SE385). The MIC of daptomycin was 1 mg/liter for both strains, and the MICs of vancomycin were 4 and 2 mg/liter for SE284 and for SE385, respectively. The in vitro bactericidal activities of daptomycin and vancomycin were evaluated by using time-kill curves. The model of foreign-body and systemic infection of neutropenic female C57BL/6 mice was used to ascertain in vivo efficacy. Animals were randomly allocated into three groups (n = 15): without treatment (controls) or treated with daptomycin at 50 mg/kg/day or vancomycin at 440 mg/kg/day. In vitro, daptomycin showed concentration-dependent bactericidal activity, while vancomycin presented time-dependent activity. In the experimental in vivo model, daptomycin and vancomycin decreased liver and catheter bacterial concentrations (P < 0.05) and increased the survival and the number of sterile blood cultures (P < 0.05) using both strains. Daptomycin produced a reduction in the bacterial liver concentration higher than 2.5 log(10) CFU/g compared to vancomycin using both strains, with this difference being significant (P < 0.05) for infection with SE385. For the catheter bacterial concentrations, daptomycin reduced the concentration of SE284 3.0 log(10) CFU/ml more than did vancomycin (P < 0.05). Daptomycin is more effective than vancomycin for the treatment of experimental foreign-body and systemic infections by biofilm-producing methicillin-resistant S. epidermidis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents / pharmacology
  • Anti-Bacterial Agents / therapeutic use*
  • Biofilms / drug effects*
  • Biofilms / growth & development
  • Catheters, Indwelling / microbiology
  • Colony Count, Microbial
  • Daptomycin / pharmacology
  • Daptomycin / therapeutic use*
  • Disease Models, Animal
  • Female
  • Humans
  • Liver / microbiology
  • Methicillin Resistance / drug effects*
  • Mice
  • Mice, Inbred C57BL
  • Microbial Sensitivity Tests / standards
  • Sepsis / drug therapy
  • Sepsis / microbiology
  • Sepsis / mortality
  • Staphylococcal Infections / drug therapy*
  • Staphylococcal Infections / microbiology
  • Staphylococcal Infections / mortality
  • Staphylococcus epidermidis / drug effects*
  • Staphylococcus epidermidis / growth & development
  • Treatment Outcome
  • Vancomycin / pharmacology
  • Vancomycin / therapeutic use*

Substances

  • Anti-Bacterial Agents
  • Vancomycin
  • Daptomycin