非生长条件下铜绿假单胞菌中spoT、relA和dksA基因对喹诺酮耐受性的功能分析。

Functional analysis of spoT, relA and dksA genes on quinolone tolerance in Pseudomonas aeruginosa under nongrowing condition.

作者信息

Viducic Darija, Ono Tsuneko, Murakami Keiji, Susilowati Heni, Kayama Shizuo, Hirota Katsuhiko, Miyake Yoichiro

机构信息

Department of Microbiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan.

出版信息

Microbiol Immunol. 2006;50(4):349-57. doi: 10.1111/j.1348-0421.2006.tb03793.x.

DOI:10.1111/j.1348-0421.2006.tb03793.x

PMID:16625057

Abstract

To assess the contribution of ppGpp in antibiotic tolerance to quinolone in Pseudomonas aeruginosa, knockout mutants of the genes involved or linked with the stringent response, such as relA, spoT and dksA, were constructed and investigated for their antibiotic susceptibility to quinolones. The survival of the dksA and spoT mutants in the presence of 8 microg/ml of ofloxacin and 1 microg/ml of ciprofloxacin were shown to be approximately 20-180 and 10-40 times respectively, higher than the same for the wild type strain. The intracellular levels of ppGpp determined with high performance liquid chromatography (HPLC) demonstrated that spoT and dksA mutants possess higher basal levels of ppGpp. The data suggest that elevated basal levels of ppGpp may be responsible for rendering these mutants tolerant to quinolones and expand the importance of ppGpp as an antimicrobial target in P. aeruginosa.

摘要

为了评估鸟苷四磷酸（ppGpp）在铜绿假单胞菌对喹诺酮类抗生素耐受性中的作用，构建了与严谨反应相关或参与其中的基因（如relA、spoT和dksA）的敲除突变体，并研究了它们对喹诺酮类抗生素的敏感性。结果显示，在存在8微克/毫升氧氟沙星和1微克/毫升环丙沙星的情况下，dksA和spoT突变体的存活率分别比野生型菌株高出约20至180倍和10至40倍。通过高效液相色谱法（HPLC）测定的ppGpp细胞内水平表明，spoT和dksA突变体具有较高的ppGpp基础水平。数据表明，ppGpp基础水平的升高可能是这些突变体对喹诺酮类抗生素产生耐受性的原因，并凸显了ppGpp作为铜绿假单胞菌抗菌靶点的重要性。