title: In vivo evaluation of mutant selection window of cefquinome against Escherichia coli in piglet tissue-cage model.
abstract: BACKGROUND
  The resistance of cephalosporins is significantly serious in veterinary clinic. In order to inhibit the bacterial resistance production, the mutant selection window (MSW) hypothesis with Escherichia coli (E. coli) ATCC 25922 exposed to cefquinome in an animal tissue-cage model was investigated.
  
  
  RESULTS
  Localized infection with E. coli was established in piglets, and the infected animals were administrated intramuscularly with various doses and intervals of cefquinome to provide antibiotic concentrations below the MIC99, between the MIC99 and the mutant prevention concentration (MPC), and above the MPC. E. coli lost susceptibility when drug concentrations fluctuated between the lower and upper boundaries of the window, which defined in vitro as the MIC99 (0.06 μg/mL) and the MPC (0.16 μg/mL) respectively. For PK/PD parameters, there were no mutant selection enrichment when T>MIC99 was ≤ 25% or T>MPC was ≥ 50% of administration interval. When T>MIC99 was > 25% and T>MPC was <50% of administration interval, resistance selection was observed. When AUC24 h/MIC99 and AUC24 h/MPC were considered, the mutant selection window extended from 32.84 h to 125.64 h and from 12.83 h to 49.09 h, respectively.
  
  
  CONCLUSIONS
  These findings demonstrate that the MSW exists in vivo for time-dependent antimicrobial agents, and its boundaries fit well with those determined in vitro. Maintenance of antimicrobial concentrations above the MPC for > 50% of administration interval is a straightforward way to restrict the acquisition of resistance in this tissue cage model. This situation was achieved with daily intramuscular doses of 1 mg cefquinome/kg body weight.
authors.affiliation: National Reference Laboratory of Veterinary Drug Residues (SCAU), College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China. 874364610@qq.com.
authors.forename: Bingxu
authors.initials: B
authors.lastname: Zhang
authors.affiliation: National Reference Laboratory of Veterinary Drug Residues (SCAU), College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China. 814470848@qq.com.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Gu
authors.affiliation: National Reference Laboratory of Veterinary Drug Residues (SCAU), College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China. 41225950@qq.com.
authors.forename: Yafei
authors.initials: Y
authors.lastname: Li
authors.affiliation: National Reference Laboratory of Veterinary Drug Residues (SCAU), College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China. 960235340@qq.com.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Li
authors.affiliation: National Reference Laboratory of Veterinary Drug Residues (SCAU), College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China. 710942824@qq.com.
authors.forename: Mengxiao
authors.initials: M
authors.lastname: Gu
authors.affiliation: National Reference Laboratory of Veterinary Drug Residues (SCAU), College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China. 814509278@qq.com.
authors.forename: Nan
authors.initials: N
authors.lastname: Zhang
authors.affiliation: National Reference Laboratory of Veterinary Drug Residues (SCAU), College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China. 1216591415@qq.com.
authors.forename: Xiangguang
authors.initials: X
authors.lastname: Shen
authors.affiliation: National Reference Laboratory of Veterinary Drug Residues (SCAU), College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China. hzding@scau.edu.cn.
authors.forename: Huanzhong
authors.initials: H
authors.lastname: Ding
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D002511:Cephalosporins / Q000493:pharmacokinetics / Q000494:pharmacology*; D015194:Diffusion Chambers, Culture / Q000662:veterinary; D004195:Disease Models, Animal; D024881:Drug Resistance, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000662:veterinary; D008826:Microbial Sensitivity Tests; D009154:Mutation; D013552:Swine
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; C068212:cefquinome