Fusidic acid resistance among clinical isolates of methicillin-resistant Staphylococcus aureus in a Taiwanese hospital

BMC Microbiol. 2011 May 12;11:98. doi: 10.1186/1471-2180-11-98.

Abstract

Background: The prevalence of resistance to fusidic acid of methicillin-resistant Staphylococcus aureus (MRSA) was increased each year in a Taiwan hospital. Thirty-four MRSA clinical isolates collected in 2007 and 2008 with reduced susceptibility to FA were selected for further evaluation the presence of resistance determinants.

Results: The most common resistance determinant was fusC, found in 25 of the 34 MRSA isolates. One of the 25 fusidic acid-resistant MRSA harboured both fusB and fusC, which is the first time this has been identified. Mutations in fusA were found in 10 strains, a total of 3 amino-acid substitutions in EF-G (fusA gene) were detected. Two substitutions with G556S and R659L were identified for the first time. Low-level resistance to fusidic acid (MICs, ≤32 μg/ml) was found in most our collection. All collected isolates carried type III SCCmec elements. MLST showed the isolates were MRSA ST239. PFGE revealed nine different pulsotypes in one cluster.

Conclusions: Our results indicate that the increase in the number of fusidic acid resistant among the MRSA isolates in this hospital is due mainly to the distribution of fusC determinants. Moreover, more than one fusidic acid-resistance mechanism was first detected in a same stain in our collection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Substitution / genetics
  • Anti-Bacterial Agents / pharmacology*
  • Bacterial Proteins / genetics
  • DNA, Bacterial / genetics
  • Drug Resistance, Bacterial*
  • Fusidic Acid / pharmacology*
  • Hospitals
  • Humans
  • Methicillin-Resistant Staphylococcus aureus / drug effects*
  • Methicillin-Resistant Staphylococcus aureus / genetics*
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification
  • Microbial Sensitivity Tests
  • Mutation, Missense
  • Peptide Elongation Factor G / genetics
  • Staphylococcal Infections / microbiology*
  • Taiwan

Substances

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • DNA, Bacterial
  • FusA protein, Staphylococcus aureus
  • FusB protein, Staphylococcus aureus
  • Peptide Elongation Factor G
  • Fusidic Acid