Potent in vitro synergism of fusidic acid (FA) and berberine chloride (BBR) against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA)

World J Microbiol Biotechnol. 2014 Nov;30(11):2861-9. doi: 10.1007/s11274-014-1712-2. Epub 2014 Aug 10.

Abstract

It was found in the present study that combined use of fusidic acid (FA) and berberine chloride (BBR) offered an in vitro synergistic action against 7 of the 30 clinical methicillin-resistant Staphylococcus aureus (MRSA) strains, with a fractional inhibitory concentration (FIC) index ranging from 0.5 to 0.19. This synergistic effect was most pronounced on MRSA 4806, an FA-resistant isolate, with a minimum inhibitory concentration (MIC) value of 1,024 μg/ml. The time-kill curve experiment showed that FA plus BBR yielded a 4.2 log10 c.f.u./ml reduction in the number of MRSA 4806 bacteria after 24-h incubation as compared with BBR alone. Viable count analysis showed that FA plus BBR produced a 3.0 log10 c.f.u./ml decrease in biofilm formation and a 1.5 log10 c.f.u./ml decrease in mature biofilm in viable cell density as compared with BBR alone. In addition, phase contrast micrographs confirmed that biofilm formation was significantly inhibited and mature biofilm was obviously destructed when FA was used in combination with BBR. These results provide evidence that combined use of FA and BBR may prove to be a promising clinical therapeutic strategy against MRSA.

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Bacterial Load
  • Berberine / pharmacology*
  • Biofilms / drug effects
  • Drug Synergism*
  • Fusidic Acid / pharmacology*
  • Humans
  • Methicillin-Resistant Staphylococcus aureus / drug effects*
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification
  • Methicillin-Resistant Staphylococcus aureus / physiology
  • Microbial Sensitivity Tests
  • Microbial Viability / drug effects
  • Staphylococcal Infections / microbiology

Substances

  • Anti-Bacterial Agents
  • Berberine
  • Fusidic Acid