Method of detecting beta-lactam antibiotic induced vancomycin resistant MRSA (BIVR)

Int J Antimicrob Agents. 2004 Jan;23(1):1-5. doi: 10.1016/j.ijantimicag.2003.05.018.


Despite the fact that the combination of vancomycin and a beta-lactam antibiotic are known to act synergistically on vancomycin-susceptible Staphylococcus aureus (VSSA), some MRSA have emerged showing antagonism to the combination of vancomycin and a beta-lactam antibiotic. These MRSA are called beta-lactam antibiotic-induced vancomycin resistant MRSA (BIVR). A method based on this antagonistic phenomenon has been devised to detect BIVR strains. The method inhibits the VSSA strain but allows the BIVR strain to grow. Forty-six commercially available beta-lactam antibiotics induced the vancomycin-resistance. Using this detection method, 717 MRSA clinical isolates obtained from eight institutes throughout Japan were thus screened and 6.3% of these were detected as BIVR when judged at 48 h.

MeSH terms

  • Drug Antagonism
  • Humans
  • Microbial Sensitivity Tests
  • Staphylococcus aureus / drug effects*
  • Staphylococcus aureus / isolation & purification
  • Staphylococcus aureus / physiology
  • Vancomycin / pharmacology*
  • Vancomycin Resistance / physiology*
  • beta-Lactams / pharmacology*


  • beta-Lactams
  • Vancomycin