Elucidation of a novel mechanism of macrolide resistance in Mycobacterium abscessus

阐明脓肿分枝杆菌大环内酯类耐药的新机制

• 批准号: 9804856
• 负责人: Pallavi Ghosh
• 金额: $ 25.37万
• 依托单位: WADSWORTH CENTER
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-06-01 至 2021-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9804856
• 关键词: Acute respiratory failure; Adenine; Affect; Affinity; Antibiotic Resistance; Antibiotics; Bacteria; Binding; Binding Sites; Chronic; Complex; Cryoelectron Microscopy; Cystic Fibrosis; Density Gradient Centrifugation; Dose; Escherichia coli; Exposure to; Family; Genes; Genetic Transcription; Genus Mycobacterium; Guanosine Triphosphate Phosphohydrolases; Heat-Shock Response; In Vitro; Infection; Investigation; Length; Lung infections; Macrolide-resistance; Macrolides; Mediating; Methyltransferase; Microbial Antibiotic Resistance; Mutation Analysis; Mycobacterium abscessus; Operative Surgical Procedures; Pathogenicity; Patients; Peptides; Peptidyltransferase; Predisposition; Protein Biosynthesis; Proteins; Regimen; Regulon; Resistance; Ribosomal RNA; Ribosomes; Role; Sequence Alignment; Site-Directed Mutagenesis; Skin Tissue; Soft Tissue Infections; Staphylococcus aureus; Structure; Sucrose; Trauma; Treatment Efficacy; Tuberculosis; antibiotic efflux; bacterial resistance; chemotherapy; cystic fibrosis patients; in vivo; inducible gene expression; insight; lung injury; mycobacterial; non-tuberculosis mycobacteria; novel; polypeptide; resistance mechanism; translation assay

Project Summary: Mycobacterium abscessus (Mab) is a rapidly growing NTM causing skin and soft tissue infections and pulmonary infections in patients with chronic lung damage, such as prior tuberculosis and cystic fibrosis. Mab stands apart as one of the most antibiotic resistant microbial species, making its infections incredibly difficult to treat. Although macrolides are a cornerstone of therapy against NTMs, they are ineffective against Mab. Intrinsic resistance to macrolides is attributed to macrolide inducible expression of methylases that modify the 23S rRNA comprising the macrolide binding site. To date this is the only known mechanism of macrolide resistance in Mab. We have identified an additional determinant, MAB_3042c, that confers inducible macrolide resistance in Mab. MAB_3042c is homologous to the universally conserved HflX proteins which have been shown to function as ribosome splitting factors. HflX proteins have not been previously implicated in antibiotic resistance suggesting that Mab_3402 could be a novel type of HflX. However, Mab_3402 also shows similarity to ribosome protection factors, which are characterized by an extended loop that inserts into the nascent polypeptide exit tunnel (NPET) and occludes the binding pocket of macrolides. In this project we will explore the function of Mab_3042 in macrolide resistance in Mab. In Aim 1, we will determine the function of MAB_3042c in ribosome splitting and ribosome protection as well as determine the role of these functions in macrolide resistance. In Aim 2 we will study the spectrum of antibiotics that are affected by MAB_3042c. The findings will provide a platform for a long-term structure- function study to gain mechanistic insight into Mab_3402c dependent macrolide resistance in Mab.

项目摘要： 结核分枝杆菌（Mab）是一种快速生长的NTM，可引起皮肤和软组织感染 和慢性肺损伤患者的肺部感染，如先前的结核病和囊性 纤维化单克隆抗体作为最具抗生素耐药性的微生物物种之一， 虽然大环内酯类药物是治疗非典型性肿瘤的基石，但它们 对Mab无效。对大环内酯类药物的内在耐药性归因于大环内酯类药物诱导表达 修饰包含大环内酯结合位点的23 S rRNA的甲基化酶。到目前为止，这是唯一一个 Mab中大环内酯类耐药已知机制 我们已经确定了一个额外的决定簇，MAB_3042c，赋予诱导型大环内酯类耐药 在Mab。MAB_3042c与普遍保守的HflX蛋白同源，已显示HflX蛋白与HflX蛋白同源。 作为核糖体分裂因子发挥作用。HflX蛋白以前没有涉及抗生素 表明Mab_3402可能是一种新类型的HflX。然而，Mab_3402还显示 与核糖体保护因子相似，其特征在于插入到核糖体中的延伸环。 新生多肽出口通道（NPET）并封闭大环内酯类的结合口袋。 本课题将探讨Mab_3042在单克隆抗体耐药中的作用。目标1： 将确定MAB_3042c在核糖体分裂和核糖体保护中的功能，以及 确定这些功能在大环内酯类耐药中的作用。在目标2中，我们将研究 受MAB_3042c影响的抗生素。调查结果将为长期结构提供一个平台- 功能研究旨在深入了解Mab中Mab_3402c依赖性大环内酯类药物耐药性的机制。