Epigallocatechin gallate synergy with ampicillin/sulbactam against 28 clinical isolates of methicillin-resistant Staphylococcus aureus

J Antimicrob Chemother. 2001 Sep;48(3):361-4. doi: 10.1093/jac/48.3.361.


Compared with ampicillin, oxacillin, cefmetazole and imipenem, the combination of ampicillin and sulbactam at a constant ratio of 2:1 showed the greatest effect against 28 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA), but MICs of ampicillin/sulbactam were still above the resistance breakpoint. When ampicillin/sulbactam was further combined with epigallocatechin gallate (EGCg, a main constituent of tea catechins), the MIC90 of ampicillin/ sulbactam was reduced to 4 mg/L, the susceptibility breakpoint. The fractional inhibitory concentration indices were between 0.19 and 0.56 in combination with 6.25 and 25 mg/L EGCg, respectively, indicating that ampicillin/sulbactam and EGCg combination may be effective against MRSA infections.

MeSH terms

  • Ampicillin / pharmacology*
  • Anti-Bacterial Agents / pharmacology*
  • Catechin / analogs & derivatives*
  • Catechin / pharmacology*
  • Drug Synergism
  • Humans
  • Methicillin Resistance
  • Microbial Sensitivity Tests
  • Staphylococcus aureus / drug effects*
  • Sulbactam / pharmacology*
  • Time Factors


  • Anti-Bacterial Agents
  • Ampicillin
  • Catechin
  • epigallocatechin gallate
  • Sulbactam