Amino acid substitutions in GyrA and ParC are associated with fluoroquinolone resistance in Mycoplasma bovis isolates from Japanese dairy calves

J Vet Med Sci. 2013;75(8):1063-5. doi: 10.1292/jvms.12-0508. Epub 2013 Mar 15.

Abstract

We investigated the contribution of quinolone resistance-determining region (QRDR) mutations to fluoroquinolone (enrofloxacin, orbifloxacin and danofloxacin) susceptibility in 58 Mycoplasma bovis isolates from dairy cattle in Japan. Fluoroquinolone non-resistant isolates (fluoroquinolone-MICs≤2 μg/ml) possessed no QRDR mutations (19 isolates) or Ser83Leu in GyrA (32 isolates). Fluoroquinolone-resistant isolates (fluoroquinolone-MICs≥4 μg/ml) possessed Ser83Leu in GyrA and Ser81Pro in ParC (3 isolates) or Ser83Phe in GyrA and Ser80Ile in ParC (4 isolates). Laboratory-derived fluoroquinolone-resistant mutants selected from 2 isolates (possessing Ser83Leu in GyrA) had an amino acid substitution in ParC at the same position (Ser80Ile or Ser81Tyr) as fluoroquinolone-resistant isolates, suggesting a concurrent amino acid substitution in ParC (Ser80 or Ser81) is important in fluoroquinolone resistance in M. bovis isolates.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Substitution
  • Animals
  • Cattle
  • Cattle Diseases / drug therapy*
  • Cattle Diseases / microbiology
  • DNA Gyrase / genetics*
  • DNA Topoisomerase IV / genetics*
  • Drug Resistance, Fungal / genetics*
  • Fluoroquinolones / pharmacology*
  • Japan
  • Microbial Sensitivity Tests
  • Mycoplasma Infections / drug therapy
  • Mycoplasma Infections / veterinary*
  • Mycoplasma bovis / drug effects
  • Mycoplasma bovis / genetics*

Substances

  • Fluoroquinolones
  • DNA Topoisomerase IV
  • DNA Gyrase