Mechanisms of antibiotic failure during osteomyelitis

骨髓炎期间抗生素失效的机制

• 批准号: 10737292
• 负责人: JAMES E CASSAT
• 金额: $ 57.71万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2028-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10737292
• 关键词: Acute; Address; Agglutinins; Antibiotic Therapy; Antibiotics; Automobile Driving; Bacteria; Bacterial Infections; Binding; Blood coagulation; Cells; Characteristics; Childhood; Chronic; Clinical; Coagulase; Coagulation Process; Communicable Diseases; Coupled; Data; Debridement; Detection; Disease; Endowment; Etiology; Exposure to; Failure; Fibrin; Fibrinogen; Freezing; Genes; Genus staphylococcus; Goals; Growth; Histologic; Human; Immune; Immune response; In Situ; In Vitro; Infection; Integration Host Factors; Intervention; Invaded; Knowledge; Label; Link; Lipids; Measures; Membrane Proteins; Microscopy; Modality; Modeling; Morbidity - disease rate; Mus; Operative Surgical Procedures; Osteomyelitis; Pathogenesis; Patients; Pattern; Phenotype; Physiological; Population; Positioning Attribute; Predisposition; Procedures; Process; Proteins; Prothrombin; Protocols documentation; Reagent; Reporter; Role; Sampling; Serum; Specimen; Staphylococcus aureus; Staphylococcus aureus infection; Testing; Tissues; Treatment Efficacy; Treatment Failure; Virulence; Virulence Factors; antibiotic tolerance; bacterial community; bacterial genetics; bone; cohort; combat; experience; experimental study; genetic approach; genome-wide; improved; improved outcome; in vitro activity; in vivo; innovation; mass spectrometric imaging; microbial; molecular imaging; mouse model; mutant; novel; novel strategies; novel therapeutic intervention; pathogen; pathogenic bacteria; pharmacologic; small molecule; transposon sequencing; treatment duration

PROJECT SUMMARY / ABSTRACT Osteomyelitis is an invasive infection of bone most commonly caused by the bacterial pathogen Staphylococcus aureus. Successful treatment of osteomyelitis requires prolonged antibiotic treatment as well as invasive surgical procedures to remove infected and nonviable bone. Despite these aggressive measures, nearly 1 in 5 patients with osteomyelitis will fail treatment. This includes patients who receive antibiotics with proven in vitro activity against the causative pathogen. These observations position osteomyelitis as a paradigm for treatment-recalcitrant infection. The goal of this proposal is to define bacterial and host factors that contribute to antibiotic failure during osteomyelitis. We hypothesize that bacterial virulence factors and host responses that promote physical shielding of bacteria in vivo contribute to antibiotic tolerance. Upon successful completion of the proposed experiments, we expect to have defined targetable mechanisms underlying antibiotic failure during osteomyelitis, with the ultimate goal of maximizing treatment efficacy, minimizing complications, and creating new approaches to detect and combat antibiotic tolerance in humans. In preliminary studies using our established murine model of osteomyelitis, we demonstrate that S. aureus rapidly develops tolerance to antibiotic killing in vivo. Histologic analyses reveal a characteristic “pseudocapsule” surrounding bacterial communities in infected bone. Pseudocapsule formation is postulated to involve key virulence factors known as coagulases and agglutinins, which together endow S. aureus with its distinctive ability to coagulate blood. We hypothesize that these virulence factors contribute to antibiotic tolerance during osteomyelitis by physically shielding bacteria within host tissues. Aim 1 will rigorously test this hypothesis, while also identifying novel determinants of antibiotic tolerance using an unbiased, in vivo bacterial screen. We will track the relative localization of antibiotics and bacteria using innovative new S. aureus reporter strains coupled with fluorescent antibiotics. Aim 2 will test the complementary hypothesis that canonical host coagulation contributes to shielding of bacteria and antibiotic tolerance. This Aim will also employ our new workflow for imaging mass spectrometry (IMS) of bone, which will enable discovery-based profiling of host analytes that form antibiotic barriers in vivo. We will also leverage IMS as a modality for label-free tracking of antibiotics in infected tissues. Aim 3 will use paired bacterial isolates and serum samples from patients with osteomyelitis to test how growth in a physiologically relevant medium alters antibiotic killing, and to link in vitro antibiotic tolerance to key clinical parameters. Collectively, the experiments in this proposal will define mechanisms leading to antibiotic tolerance during osteomyelitis, paving the way for new interventions that improve antibiotic therapy, limit treatment failure, and reduce the morbidity of this debilitating disease.

项目总结/摘要 骨髓炎是一种侵袭性感染骨最常见的细菌病原体引起的 金黄色葡萄球菌。成功治疗骨髓炎需要长期的抗生素治疗， 侵入性外科手术，以去除感染和无活力的骨。尽管采取了这些积极措施， 1/5的骨髓炎患者治疗失败。这包括接受抗生素治疗的患者， 对致病病原体的体外活性。这些观察结果将骨髓炎定位为 治疗--该提案的目标是确定有助于细菌和宿主因素， 骨髓炎期间抗生素失效。我们假设细菌毒力因子和宿主反应， 促进细菌在体内的物理屏蔽，有助于抗生素耐受性。成功完成后 在拟议的实验中，我们希望能够确定抗生素失效的靶向机制， 骨髓炎，最终目标是最大限度地提高治疗效果，减少并发症， 检测和对抗人类抗生素耐药性的新方法。 在我们建立的小鼠骨髓炎模型的初步研究中，我们证明了S。 金黄色葡萄球菌在体内迅速产生对抗生素杀伤的耐受性。组织学分析显示 感染骨中细菌群落周围的"假包膜"。假包膜的形成被假定为 涉及关键的毒力因子，如凝固酶和凝集素，它们共同赋予S。金黄色葡萄球菌及其 凝血的特殊能力。我们假设这些毒力因子有助于抗生素耐受性 在骨髓炎期间通过物理屏蔽宿主组织内的细菌。目标1将严格检验这一假设， 同时还使用无偏的体内细菌筛选鉴定抗生素耐受性的新决定因素。我们 将跟踪抗生素和细菌的相对定位使用创新的新S。金黄色葡萄球菌报告菌株 再加上荧光抗生素目的2将检验补充假设，即典型宿主凝血 有助于屏蔽细菌和抗生素耐受性。这一目标还将采用我们的新工作流程， 骨的成像质谱（IMS），这将使基于发现的主机分析物，形成 体内抗生素屏障。我们还将利用IMS作为一种无标签跟踪感染者中抗生素的方式。 组织中目的3将使用成对的细菌分离物和骨髓炎患者的血清样本来测试如何 在生理相关培养基中的生长改变了抗生素的杀伤作用，并将体外抗生素耐受性与关键因素联系起来。 临床参数总的来说，本提案中的实验将确定导致抗生素产生的机制。 骨髓炎期间的耐受性，为改善抗生素治疗的新干预措施铺平了道路， 治疗失败，并减少这种使人衰弱的疾病的发病率。