title: Fluoroquinolone resistance mechanism of clinical isolates and selected mutants of Pasteurella multocida from bovine respiratory disease in 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.
authors: College of Animal Science and Technology, Jilin Agricultural University, Xincheng Street No.#2888, Changchun 130118, P.R. China.
authors: Ling-Cong
authors: LC
authors: Kong
authors: Duo
authors: D
authors: Gao
authors: Yun-Hang
authors: YH
authors: Gao
authors: Shu-Ming
authors: SM
authors: Liu
authors: Hong-Xia
authors: HX
authors: Ma
mesh_terms: D000818:Animals; D001483:Base Sequence; D048090:Bovine Respiratory Disease Complex / Q000382:microbiology*; D002417:Cattle; D002681:China; D027081:DNA Gyrase / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D027101:DNA Topoisomerase IV / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D024841:Fluoroquinolones; D005838:Genotype; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D020125:Mutation, Missense / Q000235:genetics; D016979:Pasteurella multocida / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D017931:DNA Primers; D024841:Fluoroquinolones; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase
references: Diagn Microbiol Infect Dis. 2002 Feb;42(2):123-8
references: 11858908
references: Vet Microbiol. 2013 Dec 27;167(3-4):737-41
references: 24139632
references: J Clin Microbiol. 1998 Apr;36(4):1096-100
references: 9542944
references: Dis Aquat Organ. 2005 Nov 28;67(3):259-66
references: 16408842
references: Vet Microbiol. 2006 May 31;114(3-4):304-17
references: 16427218
references: Am J Vet Res. 2007 Aug;68(8):812-5
references: 17669019
references: Antimicrob Agents Chemother. 2009 Feb;53(2):519-24
references: 18936192
references: J Vet Med Sci. 2009 Apr;71(4):493-4
references: 19420855
references: Vet Microbiol. 2009 Oct 20;139(1-2):74-9
references: 19428195
references: Antimicrob Agents Chemother. 2010 Jun;54(6):2692-5
references: 20308376
references: Avian Pathol. 2010 Oct;39(5):333-8
references: 20954009
references: Antimicrob Agents Chemother. 2011 May;55(5):2475-7
references: 21402855
references: J Antimicrob Chemother. 2012 Jan;67(1):84-90
references: 22001175
references: J Antimicrob Chemother. 2012 Jun;67(6):1555-7
references: 22398653
references: Vet Microbiol. 2012 Aug 17;158(3-4):376-83
references: 22464155
references: J Vet Med Sci. 2013;75(8):1063-5
references: 23503166
references: Antimicrob Agents Chemother. 1995 May;39(5):1201-3
references: 7625818