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Topoisomerase mutations in trovafloxacin-resistant Staphylococcus aureus

J E Fitzgibbon1, J F John, J L Delucia

  • 1Department of Molecular Genetics and Microbiology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854-5635, USA.

Antimicrobial Agents and Chemotherapy
|August 4, 1998
PubMed

Insights

Methicillin-resistant Staphylococcus aureus (MRSA) showed high resistance to ciprofloxacin. Some MRSA strains also resisted trovafloxacin, exhibiting unique mutations in topoisomerase IV genes.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Antimicrobial Resistance

Background:

  • Staphylococcus aureus is a common cause of infections.
  • Methicillin-resistance in S. aureus (MRSA) is a significant public health concern.
  • Fluoroquinolones like ciprofloxacin and trovafloxacin are used to treat S. aureus infections.

Purpose of the Study:

  • To assess the susceptibility of Staphylococcus aureus isolates to ciprofloxacin and trovafloxacin.
  • To investigate the prevalence of resistance in methicillin-resistant S. aureus (MRSA).
  • To characterize the genetic basis of trovafloxacin resistance.

Main Methods:

  • Surveyed 201 Staphylococcus aureus isolates for antibiotic susceptibility.
  • Identified methicillin-resistant isolates (n=66).
  • Analyzed DNA topoisomerase genes (grlA) for quinoline resistance mutations in resistant strains.

Main Results:

  • 89% of MRSA isolates were resistant to ciprofloxacin.
  • 6% of MRSA isolates were also resistant to trovafloxacin.
  • Trovafloxacin-resistant strains displayed distinct quinoline resistance mutation patterns in topoisomerase genes, including grlA.

Conclusions:

  • High rates of ciprofloxacin resistance exist in MRSA.
  • Emergence of trovafloxacin resistance in MRSA is associated with specific topoisomerase mutations.
  • Understanding these genetic mechanisms is crucial for developing effective antimicrobial strategies.

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