In vitro activity of two old antibiotics against clinical isolates of methicillin-resistant Staphylococcus aureus

J Antibiot (Tokyo). 2010 Nov;63(11):657-9. doi: 10.1038/ja.2010.105. Epub 2010 Sep 29.

Abstract

The objective of this paper was to investigate the in vitro effects of fusidic acid combined with fosfomycin against methicillin-resistant Staphylococcus aureus (MRSA). In all, 196 MRSA strains isolated from three clinical specimens of human infections from hospitals in China were used in this study. The checkerboard method was used to determine whether combinations act synergistically against these strains. The susceptibility results for fusidic acid and fosfomycin were interpreted according to the guidelines of the Clinical and Laboratory Standards Institute. The combination of fusidic acid and fosfomycin demonstrated the following interactions: 87.76% (172/196) synergism, 12.24% (24/196) indifference and no antagonism was seen (minimum and maximum fractional inhibitory concentration index 0.14 and 0.75, respectively). Thus, combinations of fusidic acid and fosfomycin show synergism for most of the MRSA isolates tested in this study, and may be a future therapeutic alternative for infections caused by MRSA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / administration & dosage
  • Anti-Bacterial Agents / pharmacology*
  • China
  • Drug Synergism
  • Drug Therapy, Combination
  • Fosfomycin / administration & dosage
  • Fosfomycin / pharmacology*
  • Fusidic Acid / administration & dosage
  • Fusidic Acid / pharmacology*
  • Guidelines as Topic
  • Humans
  • Methicillin-Resistant Staphylococcus aureus / drug effects*
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification
  • Microbial Sensitivity Tests
  • Staphylococcal Infections / drug therapy
  • Staphylococcal Infections / microbiology

Substances

  • Anti-Bacterial Agents
  • Fosfomycin
  • Fusidic Acid