Molecular Mechanisms Underlying Fluoroquinolone Susceptibility and Resistance

氟喹诺酮类药物敏感性和耐药性的分子机制

• 批准号: 9276741
• 负责人: LYNN ZECHIEDRICH
• 金额: $ 38.04万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-15 至 2019-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9276741
• 关键词: Address; Affect; Amino Acids; Antibiotic Resistance; Antibiotic susceptibility; Antibiotics; Bacteria; Bacterial Antibiotic Resistance; Bacterial Infections; Biochemical; Biological Availability; Cancer Survivor; Clinical; Country; Crystallization; DNA; DNA Binding; DNA Damage; DNA Structure; Data; Databases; Diagnosis; Escherichia coli; Fluoroquinolones; Foundations; Frequencies; Funding; Gene Targeting; Genes; Genetic Polymorphism; Genome; Genomics; Goals; Gram-Negative Bacteria; HIV; Half-Life; Health Care Costs; Health Insurance Portability and Accountability Act; Hospitals; Infection; Knowledge; Laboratories; Lead; Maps; Measures; Medical center; Microbiology; Modality; Molecular; Morbidity - disease rate; Mutation; Other Genetics; Patients; Pharmaceutical Preparations; Phenotype; Physicians; Polymorphism Analysis; Predisposition; Probability; Proteins; Resistance; Resistance development; Savings; Scientist; Single Nucleotide Polymorphism; Texas; Toxic effect; Translating; Treatment Failure; Variant; Work; antimicrobial drug; clinically relevant; design; enzyme activity; fitness; fluoroquinolone resistance; genetic approach; genetic variant; genome sequencing; improved; in vivo; interdisciplinary approach; mortality; new therapeutic target; novel; novel therapeutics; prevent; protein expression; protein function; protein structure; public health relevance; reference genome; resistance mechanism; response; tool

 DESCRIPTION (provided by applicant): Antibiotic resistance is a major worldwide problem. With excellent efficacy, bioavailability, and minimal toxicity, the frequently prescribed fluoroquinolones are an extremely important drug class. The long-term goals of the Zechiedrich laboratory are to determine how gram-negative bacteria respond to and develop resistance to antimicrobial agents and to use this knowledge to improve diagnosis of antibiotic-resistant bacterial infections, to prolong the usefulness of current drugs, and to aid in the design of new therapeutic modalities. In previous funding periods, we constructed an evolving HIPAA compliant Oracle database that combines patient, hospital, and microbiological data from gram-negative clinical isolates collected since 1999. We discovered that known fluoroquinolone resistance mechanisms account for the resistance phenotype in approximately half of fluoroquinolone-resistant E. coli clinical isolates; therefore, additional unknown resistance mechanisms must exist. To uncover these mechanisms, we developed a unique approach that incorporates genome pooling, sequencing, and SNP analysis. We uncovered extremely problematic novel clinical isolates (resistant to all but two antibiotics and with very high fluoroquinolone MICs). The genomes of these isolates diverged from and could not be mapped to reference genomes. Conserved among all other fluoroquinolone-resistant pools, we found the well-known SNP in the gyrA target gene and three novel SNPs relative to drug-susceptible reference genomes. We also found 283 SNPs in 173 genes associated with fluoroquinolone resistance and resistance to specific additional antimicrobial agents. Relative to a fluoroquinolone-resistant reference genome, we found 35 novel SNPs associated with a fluoroquinolone-susceptible phenotype. The aims of this proposal are Aim 1: Predict how Identified Genetic Variants Alter the Encoded Protein Structure and Function, Aim 2: Define Function of Discovered Genetic Variants, Aim 3: Determine the Molecular Mechanisms of Discovered Protein Variants, and Aim 4: Continue to Discover Genetic Variants Associated with Fluoroquinolone Susceptibility or Fluoroquinolone Resistance Phenotypes. Our team, in the Texas Medical Center in Houston, Texas, is composed of a molecular microbiologist (Zechiedrich), a physician scientist (Hamill), a genomics expert (Sucgang), a computational biologist (Barth), and a crystallographer (Lee). The foundational knowledge gained in achieving these goals is required before new drugs or new targets for new drugs can be identified. A better understanding of how resistance arises will provide vital clues to how it may be avoided. Moreover, the identification of SNPs associated with fluoroquinolone resistance or susceptibility will provide physicians tools to prescribe antibiotics that will be effective, thus saving lives, money, and preserving the current arsenal of antibiotics.

 描述（由申请人提供）：抗生素耐药性是一个主要的世界性问题。氟喹诺酮类药物具有良好的疗效、生物利用度和最小的毒性，是一种非常重要的药物类别。Zechiedrich实验室的长期目标是确定革兰氏阴性菌如何对抗菌药物产生反应和耐药性，并利用这些知识来改善耐药细菌感染的诊断，延长现有药物的有效性，并帮助设计新的治疗方法。在之前的资助期间，我们构建了一个不断发展的符合HIPAA的Oracle数据库，该数据库结合了自1999年以来收集的革兰氏阴性临床分离株的患者、医院和微生物数据。我们发现，已知的氟喹诺酮耐药机制解释了大约一半的氟喹诺酮耐药大肠杆菌的耐药表型。大肠杆菌临床分离株;因此，必须存在其他未知的耐药机制。为了揭示这些机制，我们开发了一种独特的方法，该方法结合了基因组池，测序和SNP分析。我们发现了非常有问题的新型临床分离株（对除两种抗生素外的所有抗生素都有耐药性，并且具有非常高的氟喹诺酮MIC）。这些分离株的基因组偏离参考基因组，无法定位到参考基因组。在所有其他氟喹诺酮耐药池中，我们发现了gyrA靶基因中的众所周知的SNP和相对于药物敏感参考基因组的三个新SNP。我们还在173个基因中发现了283个SNP，这些基因与氟喹诺酮耐药和对特定其他抗菌药物的耐药相关。相对于氟喹诺酮耐药参考基因组，我们发现了35个与氟喹诺酮敏感表型相关的新SNP。本提案的目标是目标1：预测已鉴定的遗传变异如何改变编码蛋白质的结构和功能，目标2：定义已发现的遗传变异的功能，目标3：确定已发现的蛋白质变异的分子机制，目标4：继续发现与氟喹诺酮敏感性或氟喹诺酮耐药表型相关的遗传变异。我们的团队位于得克萨斯州休斯顿的得克萨斯医学中心，由分子微生物学家（Zechiedrich）、内科科学家（Hamill）、基因组学专家（Sucgang）、计算生物学家（Barth）和晶体学家（Lee）组成。在确定新药或新药的新靶点之前，需要获得实现这些目标的基础知识。更好地了解耐药性是如何产生的，将为如何避免耐药性提供重要线索。此外，与氟喹诺酮耐药性或敏感性相关的SNP的鉴定将为医生提供有效的抗生素处方工具，从而挽救生命，金钱，并保留现有的抗生素库。