Adaptation of vancomycin-resistant enterococci during bloodstream infection

血流感染期间耐万古霉素肠球菌的适应

• 批准号: 10634721
• 负责人: Daria N Van Tyne
• 金额: $ 58.2万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-03 至 2027-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10634721
• 关键词: Animals; Antibiotic Resistance; Antibiotics; Antigens; Bacteremia; Bacterial Antibiotic Resistance; Bacterial Genes; Blood; Blood Circulation; Cell Wall; Cell surface; Clinical Research; DNA-Directed RNA Polymerase; Disease; ESKAPE pathogens; Enterococcus; Enterococcus faecium; Environment; Face; Foundations; Gastrointestinal tract structure; Genes; Genetic; Genetic Transcription; Growth; Healthcare Systems; Hospitalization; Host Defense; Human; Immune; Immunocompromised Host; Individual; Infection; Infectious Diseases Research; Intervention; Mediating; Medical center; Methyltransferase; Microbial Biofilms; Molecular Probes; Muramidase; Mutation; Nutrient; Oral; Pathogenesis; Pathway interactions; Patients; Polysaccharides; Population; Population Genetics; Population Study; Prevention; Recurrence; Resistance; Ribosomal Proteins; Ribosomes; Route; Sampling; Sepsis; Site; Specimen; Time; Translations; Universities; Vancomycin Resistance; Vancomycin resistant enterococcus; Vertebrates; Work; antibiotic resistant infections; antibiotic tolerance; bacterial resistance; candidate identification; combat; comparative genomics; experience; genetic analysis; genome sequencing; genome-wide; gut colonization; improved; in vivo; insight; mortality; mouse model; neutrophil; new therapeutic target; novel; novel strategies; novel therapeutic intervention; pathogen; pressure; recurrent infection; response; therapeutic development; transmission process; whole genome

SUMMARY The long-term objective of this project is to understand how vancomycin-resistant enterococci (VRE) adapt during bloodstream infection (BSI) to better tolerate antibiotic and host immune defenses. Enterococci have evolved over hundreds of millions of years to colonize the gastrointestinal (GI) tract of animals, and they are well adapted to reside there. VRE causing BSI, however, face substantially different selective pressures, such as antibiotics in high concentrations, nutrient restriction, and host immune defenses. At our center over the past five years, patients with VRE-BSIs had a 30-day mortality rate of 36%, which was higher than BSIs due to all other ESKAPE pathogens. Additionally, VRE-BSIs are often difficult to treat, and nearly one third of patients with VRE- BSI experience either prolonged bacteremia (≥5 days), or recurrent infection within one year. Here we propose to study the population-level evolutionary dynamics of VRE sampled from the GI tract and blood of patients with VRE-BSI, and to characterize bacterial adaptations that promote VRE-BSI. Our central hypothesis is that VRE isolated from BSIs possess genetic adaptations that enable them to survive in the blood environment. In Aim 1, we will use bacterial population-level whole genome sequencing to identify genetic adaptations associated with VRE-BSI. We propose to collect matched samples from VRE GI tract surveillance specimens and VRE-BSI from approximately 150 patients, and to sequence them deeply to assess the diversity of the VRE population at each body site. We will also compare VRE-BSI populations collected over time from patients that have persistent or recurrent VRE-BSI. We will utilize comparative genomics and selection-based analyses to identify bacterial loci that are candidate targets for selection. In Aim 2, we will quantify the effect of mutations in VRE transcription and translation genes on antibiotic resistance and tolerance. We have already identified candidate adaptive mutations in RNA polymerase subunits, ribosomal proteins, a ribosome methyltransferase, and several transcriptional regulators. We will investigate: 1) The connection between antibiotic exposure and the occurrence of these mutations in the GI tract and blood of VRE-BSI patients, 2) The effects of these mutations on VRE transcription and translation, and 3) The contribution of these mutations to resistance and/or tolerance of antibiotics used to treat VRE-BSI. In Aim 3, we will determine whether mutations in the capsular polysaccharide (cps) and enterococcal polysaccharide antigen (epa) biosynthetic loci augment VRE growth and survival during BSI. We will investigate the impact of mutations that alter these cell surface-associated polysaccharides on VRE survival in whole human blood, in the presence of human neutrophils, as well as in a mouse model of VRE infection. Overall, this study has the potential to transform our understanding of how antibiotic-resistant bacteria adapt during human infection. In addition, the identification of bacterial genes and pathways under selection during VRE-BSI will lay the foundation for developing new therapeutic strategies that target antibiotic-resistant Gram-positive infections, which have high mortality and place a large burden on healthcare systems.

概括 该项目的长期目标是了解万古霉素耐药肠球菌（VRE）如何适应 在血液感染（BSI）期间，可以更好地耐受抗生素和宿主免疫防御能力。肠球菌有 进化了数亿年，以定居于动物的胃肠道（GI），它们很好 适应居住在那里。然而，VRE导致BSI，面临的选择性压力很大，例如 高浓度，养分限制和宿主免疫反应的抗生素。过去五个 几年，VRE-BSIS的患者的死亡率为36％，高于BSIS，因此由于所有其他 Eskape病原体。此外，vre-bsis通常很难治疗，几乎三分之一的VRE患者 BSI经历了长时间的细菌（≥5天）或一年内复发感染。我们在这里提出 研究从GI道中采样的VRE的种群水平进化动力学和患者的血液 VRE-BSI，并表征促进VRE-BSI的细菌适应。我们的中心假设是VRE 从BSI中分离出来具有遗传适应性，使它们能够在血液环境中生存。在AIM 1中， 我们将使用细菌种群水平的整个基因组测序来鉴定与 vre-bsi。我们建议从VRE GI道监视标本中收集匹配的样品，并从 大约有150名患者，并深入对他们进行排序以评估每个患者的多样性 身体部位。我们还将比较从持续或 复发性vre-bsi。我们将利用比较基因组学和基于选择的分析来识别细菌基因座 这是选择的候选目标。在AIM 2中，我们将量化突变在VRE转录中的影响和 抗生素耐药性和耐受性的翻译基因。我们已经确定了候选人自适应 RNA聚合酶亚基的突变，核糖体蛋白，核糖体甲基转移酶和几种 转录调节器。我们将调查：1）抗生素暴露与发生之间的联系 在胃肠道和VRE-BSI患者的血液中的这些突变中，2）这些突变对VRE的影响 转录和翻译，以及3）这些突变对抗性和/或公差的贡献 用于治疗VRE-BSI的抗​​生素。在AIM 3中，我们将确定囊囊多糖中的突变是否 （CPS）和肠球菌多糖抗原（EPA）生物合成基因座增强VRE的增长和生存期间 BSI。我们将研究改变这些细胞表面相关多糖对VRE的突变的影响 在人类嗜中性粒细胞的存在下以及VRE的小鼠模型中，整个人类血液中的生存 感染。总体而言，这项研究有可能改变我们对抗生素耐药细菌的理解 在人类感染期间适应。另外，在选择下的细菌基因和途径的鉴定 在VRE-BSI期间，将奠定基础，以开发针对抗生素抗生素的新治疗策略 革兰氏阳性感染，死亡率很高，并在医疗保健系统上烧毁。