Combatting Quinolone Antimicrobial Resistance

说明(申请人提供)：氟喹诺酮类药物是美国最常用的抗菌药物。氟喹诺酮类耐药菌和多重耐药菌是全球关注的新兴传染病病原体，而大肠杆菌是人类重要的病原菌和优秀的模式生物。Zechiedrich实验室的长期目标是确定细菌对抗菌剂的反应和抵抗，并利用这一知识延长当前药物的有效性，并帮助设计新的治疗方案，以帮助预防和抗击氟喹诺酮类和多重耐药细菌感染。这项相互竞争的更新建议的目标是确定(I)调节、(Ii)细胞作用和(Iii)多药外排泵的分子机制，以及(Iv)导致患者分离株药物MIC增加的遗传改变和(V)选择机制。凭借数以千计具有特征性和非特征性的氟喹诺酮类和多药耐药大肠埃希氏菌患者分离株和伴随的患者数据，以及德克萨斯医学中心每年900万人次的患者就诊次数，以及调查人员结合专业知识的强大实力，这些目标将实现以下具体目标：(1)了解对大肠杆菌氟喹诺酮类药物耐药至关重要的外排泵之间的相互作用和分子机制；以及(2)确定导致大肠杆菌临床分离株对氟喹诺酮类和多药耐药的分子机制、突变选择机制和遗传途径。这些具体目标将通过三种高度相互关联的方法实现：(I)分子方法将首先在确定的突变菌株中确定氟喹诺酮类药物外排泵及其调节因子之间的转录关系，然后在耐氟喹诺酮类大肠杆菌临床分离株中；(Ii)计算方法将揭示外排泵的进化相关区域指示功能；(Iii)使用成本效益高的测序技术的基因组方法将确定与临床分离菌的耐药性相关的相关可遗传变异。这些方法使用生物信息学和数据管理基础设施捆绑在一起。与公共卫生相关：由于几乎没有新的抗菌剂被开发出来，我们必须努力保护那些目前使用的抗菌剂。良好的生物利用度、低毒性和通常的低耐药频率使氟喹诺酮类药物成为内科医生保持的重要药物类别。拟议的转译研究结果将有助于医生的处方实践，并有助于设计新的治疗方案来对抗耐药细菌感染。

DESCRIPTION (provided by applicant): Fluoroquinolones are the most frequently prescribed antimicrobial agents in the United States. Fluoroquinolone- and multidrug-resistant bacteria are emerging infectious disease agents of worldwide concern and E. coli is an important human pathogen and excellent model organism. The long-term goals of the Zechiedrich laboratory are to determine how bacteria respond to and resist antimicrobial agents and to use this knowledge both to prolong the usefulness of current drugs and to aid in the design of new therapeutic protocols to help prevent and combat fluoroquinolone- and multidrug-resistant bacterial infections. The goals of this competing renewal proposal are to determine the (i) regulation, (ii) cellular roles, and (iii) molecular mechanisms of the multidrug efflux pumps, and the (iv) genetic alterations and (v) selection mechanisms that cause increased drug MICs in patient isolates. With thousands of characterized and uncharacterized fluoroquinolone- and multidrug-resistant E. coli patient isolates and the accompanying patient data, >9 million patient visits/year in the Texas Medical Center, and the strength of the combined expertise of the investigators, the goals will be achieved with the following Specific Aims: (1) Understand the interplay between and molecular mechanisms of the efflux pumps important for fluoroquinolone-resistance in E. coli; and (2) Identify molecular mechanisms, mutant selection mechanisms, and genetic pathways to fluoroquinolone- and multidrug-resistance in E. coli clinical isolates. These Specific Aims will be achieved by three highly inter-related approaches: (i) A molecular approach will determine the transcriptional relationships among the fluoroquinolone efflux pumps and their regulators using quantitative reverse- transcription PCR first in defined mutant strains and then in fluoroquinolone-resistant E. coli clinical isolates; (ii) A computational approach will uncover evolutionarily related regions of the efflux pumps indicative of functionality; and (iii) A genomic approach using cost effective sequencing technologies will identify relevant heritable variations that correlate with the drug-resistance of the clinical isolates. These approaches are tied together using bioinformatics and data management infrastructures. PUBLIC HEALTH RELEVANCE: With few new antimicrobial agents being developed, we must work to preserve those used currently. Excellent bioavailability, low toxicity and, in general, low resistance frequency, make the fluoroquinolones an important drug class to maintain in the physician's arsenal. Results from the proposed translational research will aid in the prescription practices of physicians and in the design of new therapeutic protocols to combat drug-resistant bacterial infections.