Membrane alterations and daptomycin tolerance

膜改变和达托霉素耐受性

• 批准号: 9210044
• 负责人: Elizabeth M. Fozo
• 金额: $ 34.97万
• 依托单位: UNIVERSITY OF TENNESSEE KNOXVILLE
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-01 至 2021-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9210044
• 关键词: Address; Antibiotic Resistance; Antibiotics; Bacteria; Bacterial Antibiotic Resistance; Bacterial Physiology; Body Fluids; Cardiolipins; Cell Wall; Cell membrane; Cell physiology; Cells; Cellular Membrane; Cellular Structures; Clinical; DNA Sequence Alteration; DNA cassette; Daptomycin; Data; Development; Drug resistance; Enterococcus faecalis; Etiology; Exposure to; Fat Body; Fatty Acids; Fatty acid glycerol esters; Gene Deletion; Gene Expression; Gene Expression Profiling; Genes; Genetic; Gram-Positive Bacteria; Growth; Health Personnel; Healthcare Systems; Hospitals; Image; Individual; Infection; Kinetics; Lipids; Liquid substance; Mass Spectrum Analysis; Measures; Membrane; Membrane Lipids; Metabolic Pathway; Metabolism; Microscopy; Modification; Morbidity - disease rate; Mutation; Nosocomial Infections; Organism; Pathway interactions; Patients; Pharmaceutical Preparations; Phospholipids; Physiological; Physiology; Proteins; Reporting; Research; Resistance; Resort; Role; Source; Specialist; Specificity; Supplementation; System; Testing; Training; Treatment Cost; Vancomycin Resistance; bacterial resistance; biological adaptation to stress; cardiolipin synthase; cellular targeting; combat; design; experimental study; fatty acid supplementation; fatty acid transport; membrane synthesis; metabolome; metabolomics; mortality; mutant; novel; novel therapeutics; pathogen; pathogenic bacteria; public health relevance; response; success; transcriptome; transcriptomics; transport inhibitor; weapons

 DESCRIPTION (provided by applicant): Within the past two decades, hospitals have been combating a major crisis: a rise in antibiotic resistant bacteria. To add to this crisis, there has been little success in the development of new therapeutics to treat these infections. The drug daptomycin, however, was recently approved to treat antibiotic-resistant Gram-positive bacteria. Although only used in hospital settings, resistant bacteria were discovered within two years after daptomycin was approved for use. Oftentimes, bacteria become resistant to antibiotics by genetic exchange of drug resistance cassettes; however, these daptomycin resistant bacteria did not acquire new genes but instead had mutations in genes involved in cell membrane formation or modification. Thus, membrane alterations contribute to resistance. The bacterial pathogen Enterococcus faecalis, a major cause of hospital-acquired infections, can incorporate fatty acids from host fluids which in turn leads to increased daptomycin resistance. This is not due to genetic mutation but rather physiological changes that occur upon growth in fatty acid sources. Furthermore, this increased daptomycin resistance is not due to activation of previously described pathways. This proposal is designed to address how altered membrane compositions leads to decreased sensitivity of E. faecalis to daptomycin. Specifically, it will examine how different fatty acids impact daptomycin resistance and how altered membrane composition influences interactions with the antibiotic (Aim 1, 3). This proposal will also evaluat the roles of newly identified proteins required for fatty acid incorporation and how these proteins contribute to alterations in daptomycin sensitivity. As growth in fatty acid sources leads to increased levels of the phospholipid cardiolipin, experiments will be performed discern which factor, fatty acid composition, or phospholipid content, contributes the most to decreased sensitivity to daptomycin (Aims 2, 3). This analysis will be combined with whole transcriptomic and metabolomic profiling on wild type and specific genetic mutant strains cultured in the presence and absence of fatty acids and upon exposure to daptomycin (Aim 3). Together, these studies will elucidate how fatty acid and phospholipid alterations can impact sensitivity to daptomycin and the potential use of fatty acid transport inhibitors for antibiotic development.

 描述（由申请人提供）：在过去的二十年里，医院一直在应对一个重大危机：抗生素耐药性细菌的增加。为了增加这场危机， 在开发治疗这些感染的新疗法方面几乎没有成功。然而，药物达托霉素最近被批准用于治疗耐药性革兰氏阳性菌。虽然只在医院环境中使用，但在达托霉素被批准使用后两年内就发现了耐药细菌。通常，细菌通过耐药盒的遗传交换而对抗生素产生耐药性;然而，这些达托霉素耐药细菌没有获得新的基因，而是在涉及细胞膜形成或修饰的基因中发生突变。因此，膜改变有助于抵抗。细菌病原体粪肠球菌是医院获得性感染的主要原因，它可以吸收宿主液体中的脂肪酸，从而导致达托霉素耐药性增加。这不是由于基因突变，而是由于在脂肪酸来源中生长时发生的生理变化。此外，这种增加的达托霉素抗性不是由于先前描述的途径的激活。该建议旨在解决如何改变膜组成导致E.达托霉素。具体来说，它将研究不同的脂肪酸如何影响达托霉素耐药性，以及膜组成的改变如何影响与抗生素的相互作用（目的1，3）。这项建议也将评估新发现的脂肪酸掺入所需的蛋白质的作用，以及这些蛋白质是如何与脂肪酸结合的。 有助于达托霉素敏感性的改变。由于脂肪酸来源的生长导致磷脂心磷脂水平增加，因此将进行实验，以辨别哪种因素、脂肪酸组成或磷脂含量对达托霉素敏感性降低的贡献最大（目的2、3）。该分析将与在存在和不存在脂肪酸的情况下以及暴露于达托霉素后培养的野生型和特定遗传突变株的全转录组和代谢组学分析相结合（目的3）。总之，这些研究将阐明脂肪酸和磷脂的改变如何影响对达托霉素的敏感性以及脂肪酸转运抑制剂在抗生素开发中的潜在用途。