Elucidating the mechanisms of antibiotic tolerance in Staphylococcus aureus biofilms

阐明金黄色葡萄球菌生物膜的抗生素耐受机制

基本信息

批准号：
10704541
负责人：
Jeffrey Alexander Freiberg
金额：
$ 7.61万
依托单位：
VANDERBILT UNIVERSITY MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-08-01 至 2024-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10704541
关键词：
Ablation Address Animal Model Antibiotic Therapy Antibiotic susceptibility Antibiotics Bacteremia Bacteria Bacterial Infections Cessation of life Chronic Complex Daptomycin Development Elements Endocarditis Exposure to Extracellular Matrix Fluorescence Microscopy Foundations Future Genes Genus staphylococcus Growth High Prevalence Image Individual Inductively Coupled Plasma Mass Spectrometry Infection Iron Lasers Lead Literature Manganese Mediating Metals Microbial Biofilms Modeling Morbidity - disease rate Mus Mutation Nutrient Osteomyelitis Oxidative Stress Oxygen Pathogenesis Pattern Penetration Phenotype Play Production Proteins Proteomics Public Health Reactive Inhibition Reactive Oxygen Species Regulation Regulon Research Role Sepsis Shotguns Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization Staphylococcus aureus Staphylococcus aureus infection Stress Sum Surface Testing Therapeutic Therapeutic Intervention Transition Elements United States Up-Regulation Variant Virulence Work alternative treatment antibiotic tolerance biological adaptation to stress cell community chronic infection clinically significant differential expression drug development experimental study in vivo insight mass spectrometric imaging methicillin resistant Staphylococcus aureus microbial mortality mutant novel therapeutics response stress tolerance targeted treatment transcriptome transposon sequencing

项目摘要

SUMMARY Staphylococcus aureus is one of the leading causes of bacterial infections in the United States. Invasive S. aureus infections (such as osteomyelitis, endocarditis, and bloodstream infections) are associated with relatively high rates of morbidity and mortality even when treated with appropriate antibiotics. The ability to form biofilms, microbially derived communities where cells grow attached to a surface or as a bacterial conglomerate surrounded by a complex extracellular matrix, has been associated with persistent S. aureus infections. A defining feature of bacterial biofilms, including S. aureus biofilms, is a high tolerance to antibiotics. Despite the clinical significance of the antibiotic tolerance seen in biofilm-mediated infections, the mechanism by which this occurs is poorly understood. Antibiotics have been shown to penetrate S. aureus biofilms, suggesting that there are other mechanisms besides physical occlusion involved in tolerance. One possible explanation for the increase in antibiotic tolerance is an enhanced ability to tolerate oxidative stress, which is seen in biofilm growth. Given the growing body of literature suggesting a role for oxidative stress in antibiotic-mediated killing, we hypothesize that changes in protein production that promote the bacterial oxidative stress response lead to the antibiotic tolerance phenotype seen during biofilm-mediated S. aureus infections. Furthermore, given the important role of the transition metals manganese and iron in S. aureus virulence and the oxidative stress response, we anticipate that the ability to regulate the levels of these metals and their distribution within S. aureus biofilms is integral to the antibiotic tolerance phenotype seen in S. aureus biofilms. In order to test this hypothesis, we will (1) determine the impact of antibiotic exposure on metal regulation and the oxidative stress response in S. aureus biofilms using a combination of fluorescence microscopy along with matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), (2) identify the staphylococcal genes responsible for antibiotic tolerance in biofilm growth using transposon sequencing (TnSeq) and proteomic experiments, and (3) demonstrate the in vivo significance of these findings using an animal model of osteomyelitis, a chronic biofilm-mediated S. aureus infection. The sum of this work will result in not only a better understanding of what the elements are that are responsible for antibiotic tolerance in S. aureus infections, but it will also provide new insight that will be useful in developing therapeutics and treatments aimed at reducing the morbidity and mortality of infections due to S. aureus.

概括金黄色葡萄球菌是美国细菌感染的主要原因之一。侵入性S。金黄色葡萄球菌感染（如骨髓炎、心内膜炎和血流感染）与相对即使使用适当的抗生素治疗，发病率和死亡率仍然很高。形成生物膜的能力，微生物衍生的群落，其中细胞附着在表面或作为细菌聚集体生长被复杂的细胞外基质包围，与持续的金黄色葡萄球菌感染有关。一个细菌生物膜（包括金黄色葡萄球菌生物膜）的定义特征是对抗生素的高耐受性。尽管生物膜介导的感染中抗生素耐受性的临床意义，其机制发生的情况人们知之甚少。抗生素已被证明可以穿透金黄色葡萄球菌生物膜，这表明除了物理遮挡之外，还有其他机制参与耐受性。一种可能的解释是抗生素耐受性的增加是耐受氧化应激的能力增强，这在生物膜生长中可见。鉴于越来越多的文献表明氧化应激在抗生素介导的杀伤中发挥作用，我们假设促进细菌氧化应激反应的蛋白质生产变化导致在生物膜介导的金黄色葡萄球菌感染期间观察到的抗生素耐受表型。此外，鉴于过渡金属锰和铁在金黄色葡萄球菌毒力和氧化应激中的重要作用响应，我们预计调节这些金属的水平及其在金黄色葡萄球菌内的分布的能力生物膜是金黄色葡萄球菌生物膜中抗生素耐受表型的组成部分。为了检验这个假设，我们将 (1) 确定抗生素暴露对金属调节和氧化应激反应的影响使用荧光显微镜和基质辅助激光相结合的金黄色葡萄球菌生物膜解吸/电离成像质谱 (MALDI-IMS) 和激光烧蚀电感耦合等离子体质谱 (LA-ICP-MS)，(2) 鉴定负责抗生素耐受性的葡萄球菌基因使用转座子测序 (TnSeq) 和蛋白质组学实验进行生物膜生长，并且 (3) 证明了使用骨髓炎（一种慢性生物膜介导的金黄色葡萄球菌）动物模型得出这些发现的体内意义感染。这项工作的总和不仅将导致更好地理解这些元素是什么负责金黄色葡萄球菌感染的抗生素耐受性，但它也将提供有用的新见解开发旨在降低沙门氏菌感染的发病率和死亡率的疗法和治疗方法。金黄色葡萄球菌。