Combination effect of vancomycin and beta-lactams against a Staphylococcus aureus strain, Mu3, with heterogeneous resistance to vancomycin

Antimicrob Agents Chemother. 2001 Apr;45(4):1292-4. doi: 10.1128/AAC.45.4.1292-1294.2001.


We tested the combined activity of vancomycin and seven beta-lactam antibiotics against Staphylococcus aureus clinical strain Mu3, which displays heterogeneous resistance to vancomycin. When combined with vancomycin, four of the seven tested beta-lactams exhibited an additive effect at or near their MICs, while all showed an antagonistic effect at lower, sub-MIC levels. This study implicated the unpredictable nature of combination therapy of beta-lactams and vancomycin against S. aureus with reduced susceptibility to vancomycin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Dose-Response Relationship, Drug
  • Drug Antagonism
  • Drug Interactions
  • Drug Therapy, Combination / pharmacology*
  • Microbial Sensitivity Tests
  • Peptidoglycan / biosynthesis
  • Staphylococcus aureus / drug effects*
  • Staphylococcus aureus / metabolism
  • Vancomycin / pharmacology*
  • Vancomycin Resistance*
  • beta-Lactams / pharmacology*


  • Anti-Bacterial Agents
  • Peptidoglycan
  • beta-Lactams
  • Vancomycin