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Characterization of a point mutation in the parC gene of Mycoplasma bovirhinis associated with fluoroquinolone

K Hirose1, Y Kawasaki, K Kotani

  • 1Clinical Research Center of Animal Health, Meiji Seika Kaisha Ltd, Yokohama, Kanagawa 222-8567.

Journal of Veterinary Medicine. B, Infectious Diseases and Veterinary Public Health
|July 2, 2004
PubMed

Insights

Quinolone resistance in Mycoplasma bovirhinis is linked to a specific mutation in the parC gene. This finding, observed in both lab-generated mutants and field isolates, identifies a key genetic marker for enrofloxacin resistance.

Area of Science:

  • Veterinary Microbiology
  • Molecular Biology
  • Antimicrobial Resistance

Background:

  • Mycoplasma bovirhinis is a significant pathogen in cattle.
  • Quinolone antibiotics, like enrofloxacin, are used to treat bacterial infections.
  • Emergence of quinolone resistance (QR) is a growing concern in veterinary medicine.

Purpose of the Study:

  • To investigate the genetic basis of quinolone resistance in Mycoplasma bovirhinis.
  • To identify specific gene mutations associated with enrofloxacin resistance in this species.

Main Methods:

  • Stepwise selection of Mycoplasma bovirhinis strain PG43 with increasing enrofloxacin concentrations to generate resistant mutants.
  • Analysis of the quinolone resistance-determining regions (QRDR) of key genes, including parC, gyrA, gyrB, and parE.
  • Sequencing of the parC gene in both laboratory-generated mutants and field isolates exhibiting quinolone resistance.

Main Results:

  • Quinolone-resistant mutants of Mycoplasma bovirhinis exhibited an alteration in the QRDR of the parC gene.
  • This specific parC gene alteration, a leucine to serine substitution at position 80, was also identified in field isolates of M. bovirhinis with varying levels of quinolone resistance.
  • No alterations were found in the gyrA, gyrB, or parE genes in the resistant strains.

Conclusions:

  • The study identifies a point mutation in the parC gene as the primary mechanism conferring quinolone resistance in Mycoplasma bovirhinis.
  • This parC gene mutation is a reliable marker for quinolone resistance in both experimental and naturally occurring infections.
  • This is the first report detailing quinolone resistance in M. bovirhinis mediated by a parC gene mutation.

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