A plasmid that encodes three genes for resistance to macrolide antibiotics in Staphylococcus aureus

FEMS Microbiol Lett. 1998 Oct 15;167(2):221-7. doi: 10.1111/j.1574-6968.1998.tb13232.x.


In previous letters, FEMS Microbiol. Lett. 148 (1997) 91-96, it was demonstrated that plasmid pMS97-obtained from a in 1971 clinically isolated Staphylococcus aureus strain MS8968 resistant to macrolide (Mac) antibiotics--carried an msrA gene and uncharacterized erm gene, respectively. msrA encodes a cytoplasmic membrane protein that mediates the so-called 'active Mac-efflux' (designated hereafter as msrSA') and erm encodes a methyltransferase by which a specific adenine residue of 23S rRNA is modified: methylation prevents Mac antibiotics from binding to the 50S ribosomal subunit. Interestingly, we found, in addition, an mph-like gene (hereafter referred to as mphBM) present together with msrSA' and erm on pMS97. By a BLASTP analysis, the gene mphBM product has 49% identity and 67% similarity to the amino acid sequence of MPH(2')II encoded by mphB from Escherichia coli. The order of genes was 5'-msrSA'-mphBM-3', with a 342-base-pair spacer sequence. Although we have not yet determined where erm gene is located on pMS97, the gene seems to be downstream from mphBM. This finding suggests a warning to us concerning the imprudent use of antibiotics.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Anti-Bacterial Agents / pharmacology*
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics*
  • Drug Resistance, Microbial / genetics*
  • Genes, Bacterial*
  • Humans
  • Macrolides
  • Membrane Transport Proteins*
  • Methyltransferases / genetics
  • Microbial Sensitivity Tests
  • Molecular Sequence Data
  • Plasmids*
  • Sequence Analysis, DNA
  • Staphylococcus aureus / drug effects
  • Staphylococcus aureus / genetics*
  • Staphylococcus aureus / growth & development


  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Macrolides
  • Membrane Transport Proteins
  • MphBM protein, Staphylococcus aureus
  • msrA protein, Staphylococcus epidermidis
  • Methyltransferases

Associated data

  • GENBANK/AB013298