Early use of daptomycin versus vancomycin for methicillin-resistant Staphylococcus aureus bacteremia with vancomycin minimum inhibitory concentration >1 mg/L: a matched cohort study

Clin Infect Dis. 2013 Jun;56(11):1562-9. doi: 10.1093/cid/cit112. Epub 2013 Feb 28.


Background: Recent reports have described decreased effectiveness with vancomycin treatment for methicillin-resistant Staphylococcus aureus bacteremia (MRSAB) when the vancomycin minimum inhibitory concentration (MIC) is >1 µg/mL.

Methods: This matched, retrospective cohort study compared the clinical effectiveness of daptomycin with that of vancomycin for the treatment of MRSAB with vancomycin MICs >1 µg/mL. The primary outcome was clinical failure, defined as a composite of 30-day mortality or bacteremia persisting for ≥7 days.

Results: One hundred seventy patients were matched 1:1 with respect to the antimicrobial administered. In the daptomycin group, all patients received <72 hours of vancomycin (median, 1.7 days [interquartile range, 1.1-2.3 days]) prior to switching to daptomycin. The rate of clinical failure at 30 days was significantly lower in the daptomycin arm compared to the vancomycin arm (20.0% vs 48.2%; P < 0.001). Both 30-day mortality and persistent bacteremia were significantly lower in the daptomycin group compared to the vancomycin group (3.5% vs 12.9% [P = .047] and 18.8% vs 42.4% [P = .001], respectively). Logistic regression confirmed the association between vancomycin treatment and increased risk of clinical failure (adjusted odds ratio, 4.5; 95% confidence interval, 2.1-9.8).

Conclusions: This is the first matched study comparing early daptomycin versus vancomycin for the treatment of MRSAB when the vancomycin MIC is >1 µg/mL. Treatment with daptomycin resulted in significantly improved outcomes, including decreased 30-day mortality and persistent bacteremia. These results support the practice of switching early from vancomycin to daptomycin for the treatment of MRSAB when the vancomycin MIC is >1 µg/mL.

Keywords: bacteremia; daptomycin; methicillin-resistant Staphylococcus aureus; vancomycin.

MeSH terms

  • Adult
  • Anti-Bacterial Agents / pharmacology
  • Anti-Bacterial Agents / therapeutic use*
  • Bacteremia / drug therapy*
  • Bacteremia / microbiology
  • Chi-Square Distribution
  • Cohort Studies
  • Daptomycin / pharmacology
  • Daptomycin / therapeutic use*
  • Female
  • Humans
  • Male
  • Methicillin-Resistant Staphylococcus aureus / drug effects*
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification
  • Microbial Sensitivity Tests
  • Middle Aged
  • Multivariate Analysis
  • Proportional Hazards Models
  • Staphylococcal Infections / drug therapy*
  • Staphylococcal Infections / microbiology
  • Treatment Outcome
  • Vancomycin / pharmacology
  • Vancomycin / therapeutic use*


  • Anti-Bacterial Agents
  • Vancomycin
  • Daptomycin