PLASMID MEDIATED QUINOLONE RESISTANCE

质粒介导的喹诺酮耐药性

• 批准号: 6163951
• 负责人: GEORGE A JACOBY
• 金额: $ 10.94万
• 依托单位: LAHEY CLINIC
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-15 至 2002-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6163951
• 关键词: DNA gyrase; DNA topoisomerases; Escherichia coli; Klebsiella pneumoniae; chemical binding; chromosomes; drug resistance; gene expression; genetic promoter element; gram negative bacteria; messenger RNA; microorganism culture; nucleic acid sequence; plasmids; protein purification; quinoline; tissue /cell culture

DESCRIPTION (Adapted from the Applicant's Abstract): Quinolones are widely used antimicrobial agents because of their broad antibacterial spectrum and reliable action against otherwise resistant bacteria. Quinolone resistance has been slowly but steadily increasing. It has been previously shown that various chromosomal mutations contribute to this resistance, but plasmid-mediated resistance has not been shown to occur. The Principal Investigator has discovered a 56 kb, broad host range, multiresistance plasmid in clinical isolates of Klebsiella pneumoniae and Escherichia coli that confers quinolone resistance in a variety of gram negative bacteria. The level of plasmid-mediated quinolone resistance is low in wild-type E. coli, but higher degrees of quinolone resistance can be selected for when the plasmid is present. The quinolone resistance (qnr) locus has been cloned and sequenced from the 56 kb plasmid. The nucleotide sequence is unique, but the predicted protein (termed Qnr) has similarity to the microcin B17 immunity protein which protects DNA gyrase from microcin inhibition. The aims of the proposal are to identify the qnr promoter by sequencing the 5' end of its mRNA, to construct a high level expression and purification system for Qnr, to study the ability of purified Qnr to protect DNA gyrase and topoisomerase IV from quinolone inhibition, to explore binding of Qnr to these quinolone targets and their subunits, and to establish the prevalence of qnr mediated resistance, both at the hospital where it was first detected and in samples of resistant bacteria from other sources. Understanding how qnr acts may help to curtail the rise in quinolone resistance and may also provide fundamental insights into aspects of DNA replication.

描述（改编自申请人的摘要）：喹诺酮类药物是 抗菌药物因其广泛的抗菌作用而被广泛使用 谱和对其他耐药细菌的可靠作用。 喹诺酮类耐药性一直在缓慢但稳定地增加。它有 之前已经表明，多种染色体突变会导致 这种抗性，但质粒介导的抗性尚未被证明 发生。首席研究员发现了一个 56 kb 的广泛主机 克雷伯氏菌临床分离株中的范围、多重耐药质粒 肺炎链球菌和大肠杆菌使喹诺酮类药物产生耐药性 多种革兰氏阴性菌。质粒介导的水平 野生型大肠杆菌对喹诺酮类药物的耐药性较低，但耐药程度较高 当质粒存在时，可以选择喹诺酮抗性。 喹诺酮抗性 (qnr) 位点已从 56 kb 质粒。核苷酸序列是独特的，但预测的 蛋白质（称为 Qnr）与 microcin B17 免疫蛋白相似 它可以保护 DNA 旋转酶免受小菌素抑制。该组织的目标 建议通过对 5' 端进行测序来鉴定 qnr 启动子 其mRNA，构建高水平表达和纯化系统 对于 Qnr，研究纯化的 Qnr 保护 DNA 旋转酶的能力和 来自喹诺酮抑制的拓扑异构酶 IV，探索 Qnr 的结合 这些喹诺酮靶标及其亚基，并建立 qnr 介导的耐药性的流行，无论是在其所在的医院 首先在其他来源的耐药细菌样本中检测到。 了解 qnr 的作用可能有助于遏制喹诺酮类药物的增加 抵抗力，还可能提供对 DNA 各方面的基本见解 复制。