Identifying the contribution of zinc limitation to antibiotic tolerance during S. aureus infection

确定金黄色葡萄球菌感染期间锌限制对抗生素耐受性的影响

• 批准号: 10192892
• 负责人: Brian Patrick Conlon
• 金额: $ 24.09万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-01 至 2023-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10192892
• 关键词: Antibiotic Therapy; Antibiotic susceptibility; Antibiotics; Automobile Driving; Bacterial Infections; Cell physiology; Cells; Cessation of life; Chelating Agents; Chronic; Citric Acid Cycle; Coupling; DNA biosynthesis; Diet; Disease; Drops; Environment; Environmental Risk Factor; Evolution; Exhibits; Exposure to; Genetic Transcription; Growth; Homeostasis; Immune; Immune system; In Vitro; Infection; Innate Immune Response; Innate Immune System; Invaded; Knowledge; Leukocyte L1 Antigen Complex; Measures; Mediating; Metabolic; Metabolism; Metals; Micronutrients; Modeling; Nutritional Immunity; Phenotype; Physiological; Population; Predisposition; Process; Protein Biosynthesis; Proteins; Public Health; Reactive Oxygen Species; Regimen; Relapse; Resistance; Resolution; Role; Route; Sepsis; Staphylococcus aureus; Staphylococcus aureus infection; Starvation; Testing; Transition Elements; Translation Process; Translations; Treatment Failure; Zinc; Zinc deficiency; antibiotic tolerance; bactericide; cofactor; genetic manipulation; human pathogen; immunoregulation; improved; in vivo; metalloenzyme; mouse model; pathogen; stressor

Abstract Staphylococcus aureus is a major human pathogen responsible for numerous chronic and relapsing infections. These infections often do not respond to treatment, leading to approximately 20,000 annual deaths in the US alone. Paradoxically, during in vitro susceptibility testing, isolates from these infections frequently exhibit full sensitivity to administered antibiotics, suggesting that environmental factors present in the host may influence S. aureus antibiotic susceptibility. Understanding how these factors control antibiotic susceptibility will improve the resolution of recalcitrant S. aureus infection, and slow the evolution of resistance. We have previously shown that extrinsic stressors within the host including exposure to reactive oxygen species (ROS) produced by the host innate immune system inadvertently render subpopulations of S. aureus tolerant to antibiotic killing by suppressing S. aureus metabolic activity. However, ROS exposure cannot fully account for the tolerant state of S. aureus in vivo, suggesting that other unidentified factors present within the host reduce antibiotic efficacy against S. aureus. Here we propose that the host immune protein calprotectin induces an antibiotic tolerant state in S. aureus by starving the pathogen of zinc. Zinc is an essential cofactor required for the activity of numerous bacterial metalloenzymes that carry out the major host processes. Zinc- starved populations of S. aureus demonstrate significantly reduced rates of DNA synthesis, transcription, and translation, and these processes represent the primary targets of bactericidal antibiotic action. Host-mediated zinc sequestration may therefore inadvertently render S. aureus tolerant to antibiotic killing by reducing the activity of major antibiotic targets. Overall, we hypothesize that zinc limitation induces an antibiotic tolerant state in S. aureus during infection and that altering zinc availability through diet or immune modulation will influence antibiotic efficacy within the host. In AIM1 we will probe the role of target inactivation in driving S. aureus antibiotic tolerance by directly reducing global DNA replication and translation rates, and measuring the impact on S. aureus antibiotic susceptibility. We will then assess the contribution of host-mediated zinc sequestration in inducing this phenotype. In AIM2 we will move into a mouse model of S. aureus sepsis to assess the relevance of altering physiological zinc availability (through diet or genetic manipulation) to enhance or suppress antibiotic efficacy against S. aureus. In all, we expect that our findings will help improve our understanding of SA antibiotic susceptibility, and elucidate how such knowledge can be exploited to resolve currently unresolvable infections.

抽象的 金黄色葡萄球菌是导致许多慢性和复发性疾病的主要人类病原体 感染。这些感染通常对治疗没有反应，每年导致约 20,000 人死亡 仅在美国。矛盾的是，在体外药敏试验期间，经常从这些感染中分离出来 对所施用的抗生素表现出完全敏感性，这表明宿主体内存在的环境因素可能 影响金黄色葡萄球菌抗生素敏感性。了解这些因素如何控制抗生素敏感性将 提高顽固性金黄色葡萄球菌感染的解决率，并减缓耐药性的演变。 我们之前已经表明，宿主体内的外在应激源，包括暴露于活性氧 由宿主先天免疫系统产生的物种（ROS）无意中产生金黄色葡萄球菌亚群 通过抑制金黄色葡萄球菌代谢活性来耐受抗生素杀死。然而，ROS暴露并不能完全 解释了金黄色葡萄球菌在体内的耐受状态，表明金黄色葡萄球菌内存在其他未识别的因素 宿主降低抗生素对金黄色葡萄球菌的功效。这里我们提出宿主免疫蛋白钙卫蛋白 通过使病原体缺锌，在金黄色葡萄球菌中诱导抗生素耐受状态。锌是必需的辅助因子 执行主要宿主过程的许多细菌金属酶的活性所必需的。锌- 饥饿的金黄色葡萄球菌群体的 DNA 合成、转录和代谢率显着降低 翻译，这些过程代表了抗生素杀菌作用的主要目标。宿主介导 因此，锌的螯合可能会通过减少金黄色葡萄球菌的 主要抗生素靶标的活性。总的来说，我们假设锌限制会导致抗生素耐受 金黄色葡萄球菌感染期间的状态，通过饮食或免疫调节改变锌的可用性将 影响宿主内抗生素的功效。 在 AIM1 中，我们将通过直接探究目标失活在驱动金黄色葡萄球菌抗生素耐受性中的作用 降低整体 DNA 复制和翻译率，并测量对金黄色葡萄球菌抗生素的影响 易感性。然后我们将评估宿主介导的锌螯合在诱导这种情况中的贡献 表型。在 AIM2 中，我们将进入金黄色葡萄球菌脓毒症小鼠模型，以评估改变的相关性 生理锌可用性（通过饮食或基因操纵）可增强或抑制抗生素功效 对抗金黄色葡萄球菌。总而言之，我们希望我们的发现将有助于提高我们对 SA 抗生素的了解 易感性，并阐明如何利用这些知识来解决目前无法解决的感染问题。