Fluoroquinolone Resistance Mechanism of Clinical Isolates and Selected
Mutants of Pasteurella multocida from Bovine Respiratory Disease in
China |
| |
| Authors: | Ling-Cong KONG Duo GAO Yun-Hang GAO Shu-Ming LIU Hong-Xia MA |
| |
| Institution: | 1)College of Animal Science and Technology, Jilin Agricultural University, Xincheng Street No.#2888, Changchun 130118, P.R. China |
| |
| Abstract: | The minimum inhibitory
concentrations (MICs), mutation prevention concentrations (MPCs) and contribution of
quinolone resistance-determining region (QRDR) mutations to fluoroquinolone
(ciprofloxacin, enrofloxacin and orbifloxacin) susceptibility in 23 Pasteurella
multocida (Pm) isolates were investigated.
Fluoroquinolone-susceptible isolates (MICs ≤0.25 µg/ml,
9 isolates) had no QRDR mutations, and their respective MPCs were low.
Fluoroquinolone-intermediate isolates (MICs=0.5 µg/ml,
14 isolates) had QRDR mutations (Asp87 to Asn or Ala84 to Pro in gyrA),
and their respective MPCs were high (4–32 µg/ml).
First-step mutants (n=5) and laboratory-derived highly resistant fluoroquinolone mutants
(n=5) also had QRDR mutations. The MICs of fluoroquinolones for mutant-derived strains
were decreased in the presence of efflux inhibitors. The results indicated that the
fluoroquinolone resistance of Pm is mainly due to multiple target gene
mutations in gyrA and parC and the overexpression of
efflux pump genes. |
| |
| Keywords: | efflux pump fluoroquinolone resistance Pasteurella multocida plasmid target mutation |
|
|
