Function and regulation of the intrinsic antibiotic resistome of Neisseria gonorrhoeae

淋病奈瑟菌内在抗生素耐药性的功能和调控

• 批准号: 10201478
• 负责人: William Maurice Shafer
• 金额: $ 46.55万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-24 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10201478
• 关键词: Acinetobacter baumannii; Africa; Aminoglycoside resistance; Aminoglycosides; Animals; Anti-Bacterial Agents; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Antimicrobial Cationic Peptides; Antimicrobial Resistance; Azithromycin; Bacteria; Cefixime; Ceftriaxone; Cephalosporins; Clinical; Clinical Trials; Communities; Country; Data; Defect; Developed Countries; Developing Countries; Development; Disease; Drug Targeting; Female; Future; GC gene; Gene Expression; Generations; Genes; Genetic Screening; Gentamicins; Gonorrhea; Gram-Negative Bacteria; Gynecologic; Health; Homeostasis; Host Defense; Human; Incidence; Infection; Infectious Agent; Knowledge; Laboratories; Medical; Membrane; Modeling; Mucous Membrane; Multi-Drug Resistance; Mus; Mutation; Nature; Neisseria gonorrhoeae; Pharmaceutical Preparations; Physiological; Predisposition; Process; Proteins; Pseudomonas aeruginosa; Recording of previous events; Regulation; Report (document); Reporting; Research; Resistance; Resistance development; Resources; Sensory; Sepsis; Sexually Transmitted Diseases; Societies; Structure; Sulfonamides; Surface; System; Techniques; Therapeutic; Transcriptional Regulation; Treatment Protocols; United States; Vaccines; Woman; Work; antimicrobial; attenuation; bacterial resistance; base; cell envelope; clinical efficacy; clinical practice; combat; experience; human pathogen; insight; male; male health; mouse model; mutant; novel; novel therapeutics; pathogenic bacteria; programs; reproductive; reproductive tract; resistance gene; response; screening; success; transcriptome sequencing; uptake

Neisseria gonorrhoeae (the gonococcus; [Gc]) causes both localized, uncomplicated infections at mucosal surfaces and more invasive forms of disease that can have severe medical consequences for the reproductive and general health of men and women. In the United States it is estimated that the incidence of gonorrhea is at least 850,000 cases per year while the worldwide incidence in 2012 was reported to be 78 million cases. In addition to the global problems of disease incidence and impact of gonorrhea on human health, Gc strains have developed decreased susceptibility or clinical resistance to front-line antibiotics currently used in dual therapy (e.g., ceftriaxone and azithromycin) in the USA and other developed countries. Our research program is dedicated to understanding the intrinsic systems possessed by Gc that allow it to resist classical antibiotics as well as cationic antimicrobial peptides/proteins (CAMPs) that participate in innate host defense. In the absence of new antibiotics, especially those recognizing unexploited targets, information regarding the development of resistance to existing antibiotics likely to enter clinical practice is critical. For instance, gentamicin has been used extensively in Africa to treat gonorrhea but resistance data from this part of the world is scant. This is unfortunate because gentamicin has been suggested to be an alternative antibiotic for treatment of gonorrhea in developed countries. We have evidence that loss of a sensory two component system (TCS) termed MisR/MisS results in Gc hyper-susceptibility to both gentamicin (as well as other aminoglycosides) and CAMPs, but not other antibiotics. A recent report documented that loss of the MisR/MisS TCS conferred a survival defect on Gc as assessed in a female mouse model of lower genital tract infection. We hypothesize that such attenuation of Gc was due, in part, to a reduced capacity of MisR-negative Gc to regulate genes important for resistance to host-derived CAMPs. The selective sensitivity of MisR-negative Gc to aminoglycosides and CAMPs is consistent with the self-promoted uptake model invoked for how these antimicrobials enter Pseudomonas aeruginosa and traverse the cell envelope. We will now build on the progress made in our initial studies. In Specific Aim 1 we will use genetic screening techniques, an experimental female mouse infection model and analysis of clinical isolates expressing decreased gentamicin susceptibility to further define the repertoire of Gc genes that contribute to intrinsic gentamicin resistance. We hypothesize that the identified genes will encode proteins that participate in cell envelope structure, membrane integrity and membrane homeostasis that work in unison to impact levels of Gc resistance to aminoglycosides and CAMPs. In Specific Aim 2 we will ascertain the responsiveness of Gc to sub-lethal levels of gentamicin and determine the responsible genes. In Specific Aim 3 we will define the physiological consequences of mutations in the identified genes that influence Gc susceptibility to gentamicin. The results from this work will provide basic knowledge as to how human pathogens like Gc control expression of genes involved in intrinsic resistance to antimicrobials.

淋病奈瑟菌（淋球菌；[Gc]）会引起粘膜表面局部、简单的感染和更具侵袭性的疾病，可能对男性和女性的生殖和总体健康造成严重的医疗后果。据估计，美国每年至少有 85 万例淋病发病，而 2012 年全世界的淋病发病率据报告为 7,800 万例。除了淋病发病率和对人类健康影响的全球性问题外，Gc 菌株对美国和其他发达国家目前用于双重治疗的一线抗生素（例如头孢曲松和阿奇霉素）的敏感性或临床耐药性也降低。我们的研究项目致力于了解 Gc 所拥有的内在系统，这些系统使其能够抵抗经典抗生素以及参与先天宿主防御的阳离子抗菌肽/蛋白质 (CAMP)。在缺乏新抗生素的情况下，特别是那些识别未开发靶点的抗生素，有关可能进入临床实践的现有抗生素耐药性发展的信息至关重要。例如，庆大霉素在非洲被广泛用于治疗淋病，但该地区的耐药性数据却很少。这是不幸的，因为庆大霉素已被建议作为发达国家治疗淋病的替代抗生素。我们有证据表明，称为 MisR/MisS 的感觉双组分系统 (TCS) 的缺失会导致 Gc 对庆大霉素（以及其他氨基糖苷类）和 CAMP 高度敏感，但对其他抗生素不敏感。最近的一份报告记录了，在雌性小鼠下生殖道感染模型中评估，MisR/MisS TCS 的缺失会导致 Gc 出现生存缺陷。我们假设 Gc 的这种减弱部分是由于 MisR 阴性 Gc 调节对宿主来源的 CAMP 抗性重要的基因的能力降低。 MisR 阴性 Gc 对氨基糖苷类和 CAMP 的选择性敏感性与这些抗菌药物如何进入铜绿假单胞菌并穿过细胞膜的自我促进摄取模型一致。我们现在将在初步研究取得的进展的基础上再接再厉。在具体目标 1 中，我们将使用基因筛查技术、实验性雌性小鼠感染模型以及对表达庆大霉素敏感性降低的临床分离株进行分析，以进一步确定导致庆大霉素内在耐药性的 Gc 基因库。我们假设，已识别的基因将编码参与细胞包膜结构、膜完整性和膜稳态的蛋白质，这些蛋白质协同作用，影响 Gc 对氨基糖苷类和 CAMP 的抗性水平。在具体目标 2 中，我们将确定 Gc 对亚致死水平庆大霉素的反应性并确定相关基因。在具体目标 3 中，我们将定义影响 Gc 对庆大霉素敏感性的已识别基因突变的生理后果。这项工作的结果将提供关于 Gc 等人类病原体如何控制与抗菌药物内在耐药性有关的基因表达的基本知识。