4.7 Article

Impact of plasmid-borne oqxAB on the development of fluoroquinolone resistance and bacterial fitness in Escherichia coli

期刊

JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY
卷 72, 期 5, 页码 1293-1302

出版社

OXFORD UNIV PRESS
DOI: 10.1093/jac/dkw576

关键词

-

资金

  1. National Natural Science Foundation of China [31272610]
  2. National Key Basic Research Program of China [2013CB127200]

向作者/读者索取更多资源

Objectives: To investigate the impact of plasmid-borne oqxAB genes on the development of fluoroquinolone resistance, mutations and bacterial fitness in Escherichia coli. Methods: MICs andmutation prevention concentrations were compared among E. coli strain TOP10 and two corresponding transformants harbouring the OqxAB-encoding plasmids. Mutants were selected by serial passages with the 0.5-fold MIC of ciprofloxacin, and were randomly selected to determine mutations. Bacterial fitness was evaluated by competition assays in vitro and in vivo. Results: The oqxAB-carrying plasmids contributed to a 4-8-fold increase in the ciprofloxacin MIC and increased the ciprofloxacin mutation prevention concentration by 8-16-fold. The MIC of ciprofloxacin for the two transformants increased faster than that of E. coli TOP10 by serial passaging. Novel mutations in gyrB (A468P or F458V) were first observed. Mutations in gyrA were distributed at codons 87 and 83 in the two transformants, whereas mutation A119E in gyrA dominated in the TOP10 mutants. Although the two oqxAB-bearing plasmids caused a decrease in fitness in vitro, their fitness increased when combined with more than one chromosomal mutation, and clear biological benefits were observed in vivo. The mutations in gyrB were associated with a fitness cost, which could be compensated for by additional mutations. The novel mutation gyrA DS83 significantly reduced biological fitness both in vitro and in vivo, and was thus quickly replaced by more beneficial mutations in the population. Conclusions: The possession of plasmid-borne oqxAB may facilitate the evolution of fluoroquinolone resistance, and the fitness cost of OqxAB-encoding plasmids could be compensated by additional chromosomalmutations.

作者

我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。

评论

主要评分

4.7
评分不足

次要评分

新颖性
-
重要性
-
科学严谨性
-
评价这篇论文

推荐

暂无数据
暂无数据