COMBATTING QUINOLONE ANTIMICROBIAL RESISTANCE

说明(申请人提供)：喹诺酮类药物是一些最常用的广谱抗菌剂。对这些药物的耐药性已成为一个严重的公共卫生问题。药物靶标拓扑异构酶的突变会导致耐药性，这是有充分证据的。此外，据报道，多药外排泵AcrAB的过度生产会导致临床分离的大肠埃希菌对喹诺酮类药物产生耐药性。 我们的长期目标是确定细菌对喹诺酮类药物暴露的反应，并利用这一知识设计更有效的治疗方法。本研究的目的是确定导致临床分离的大肠埃希菌对喹诺酮类药物耐药的基因改变，并确定喹诺酮类药物耐药水平和频率、突变和其他患者协变量之间的相互关系。中心假设是，在喹诺酮类药物治疗后，导致耐药的突变是相加发生的，从拓扑异构酶突变开始，最终包括AcrAB的过度生产，最具耐药性的菌株包含额外的突变，包括另一个多药外排泵。初步数据支持这些假设。任何多药外排泵的过量生产都会产生深远的治疗后果；除了喹诺酮类药物外，来自多种不同类别的抗菌剂对这些细菌都是无效的。 凭借研究人员的基础、临床、统计、基因组和生物信息学专业知识以及我们患者群体的规模，我们独一无二地准备实现以下具体目标： (1)对引起临床分离株对喹诺酮类药物耐药的基因改变进行鉴定和分类。我们将使用高通量方法来检测编码喹诺酮耐药基因的突变。统计方法将被用来分析突变之间的潜在相互关系。 (2)对患者数据进行前瞻性分析。我们将：(A)使用针对特定目标1开发的高通量方法来确定从德克萨斯医疗中心住院患者分离的大肠杆菌与来自世界各地不同财团的分离株相比发生的基因变化；(B)进行基因组分型；(C)根据患者的人口学和临床数据分析这些数据，以确定喹诺酮耐药的可能原因。在我们更好地了解细菌应对药物压力的机制之前，我们无法设计出更好的抑制剂或控制抗菌素耐药性感染。

DESCRIPTION (provided by applicant): Quinolones are some of the most frequently used, broad-spectrum antimicrobial agents. Resistance to these drugs has become a critical public health problem. Mutations in the drug target topoisomerases that result in drug resistance are well documented. In addition, overproduction of the multidrug efflux pump AcrAB has been reported to result in quinolone resistance in clinical isolates of E. coli. Our long-range goal is to determine how bacteria respond to exposure to quinolone agents and to use this knowledge to design more effective treatments. A goal of the present proposal is to identify the genetic alterations that lead to quinolone resistance in clinical E. coli strains and to determine the interrelationship between levels and frequency of quinolone resistance, the mutations, and other patient covariates. The central hypothesis is that following quinolone treatment, mutations conferring resistance occur additively, beginning with mutations in the topoisomerases and ultimately including overproduction of AcrAB and that the most resistant isolates contain additional mutations, including another multidrug efflux pump. Preliminary data support these hypotheses. Overproduction of any multidrug efflux pump has far reaching therapeutic consequences; antimicrobial agents from multiple different categories, in addition to the quinolones, would be ineffective against these bacteria. With the combined basic, clinical, statistical, genomic, and bioinformatic expertise of the investigators and the size of our patient population, we are uniquely poised to carry out the following specific aims: (1) Identify and categorize genetic alterations that cause quinolone resistance in clinical isolates. We will use high through-put methods to detect mutations in the genes that encode quinolone resistance. Statistical methods will be used to analyze potential interrelationships between the mutations. (2) Perform a prospective analysis of patient data. We will: (a) use the high-throughput methods developed in specific aim 1 to determine the genetic alterations occurring in E. coli isolated from patients hospitalized in the Texas Medical Center compared to isolates from various consortia around the world; (b) perform genome typing; (c) analyze these data with respect to demographic and clinical data for the patients to determine the probable causes of quinolone resistance. Until we have a better understanding of the mechanisms used by bacteria to cope with drug pressure, we cannot design better inhibitors or control antimicrobial resistant infections.