Genetic determinants of antimicrobial peptide resistance in Gram negative bacteri

革兰氏阴性菌抗菌肽耐药性的遗传决定因素

• 批准号: 7914372
• 负责人: Hyunwoo Lee
• 金额: $ 23.55万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-13 至 2011-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7914372
• 关键词: Acinetobacter baumannii; Animals; Anti-Bacterial Agents; Anti-Infective Agents; Antibiotics; Antimicrobial Resistance; Attenuated; Bacteria; Charge; Clinic; Clinical; Clinical Trials; Defensins; Escherichia coli; Genes; Genetic Determinism; Genetic Techniques; Goals; Gram-Negative Bacteria; Host Defense; Human; In Vitro; Infection; Knowledge; Measures; Methods; Monitor; Multi-Drug Resistance; Names; Natural Resistance; Pathogenesis; Peptides; Polymyxins; Pseudomonas aeruginosa; Relative (related person); Research; Resistance; Resistance development; Risk; Staging; Structure; Testing; Time; Topical agent; Work; antimicrobial peptide; bacterial resistance; bactericide; base; clinical practice; cost; dermcidin; drug resistant bacteria; follow-up; human neutrophil peptide 1; in vivo; insight; knockout gene; magainin; mutant; neutrophil; novel; pathogen; protegrin PG-1; research study; resistance mechanism

DESCRIPTION (provided by applicant): Antimicrobial peptides are a promising class of new antibacterial agents, particularly due to their potent activity against bacteria resistant to conventional antibiotics. Only a few such peptides, e.g., polymyxins, have been in clinical practice, and to date polymyxins are the only antibiotic to which multidrug-resistant Gram-negative bacteria such as Pseudomonas aeruginosa and Acinetobacter baumannii remain susceptible. Antimicrobial peptides that structurally differ from the cyclic lipopeptide polymyxins are now at various stages of clinical trials as systemic and topical agents, e.g., cationic 1-helical pexiganan and 2-sheet plectasin. However, recent studies have demonstrated that the use of antimicrobial peptides in clinics will eventually induce a high level of bacterial resistance to them. In its worst scenario, bacteria normally controlled by human endogenous antimicrobial peptides may cause unmanageable infections. Our goal in this project is to identify and characterize genetic determinants of bacterial intrinsic resistance to human antimicrobial peptides such as cationic 2-sheet neutrophil peptide-1 (HNP-1) and anionic dermcidin-1, as a prerequisite to assessing the potential risk of bacterial resistance to them and overcoming such resistance. In Gram-negative pathogens, mechanisms of resistance to these classes of antimicrobial peptides are virtually unknown. To expedite the discovery of resistance determinants, we have developed a new microarray-based method, monitoring of gene knockouts (MGK). MGK allows simultaneous analysis of the relative abundance of thousands of mutants grown in a culture. Our preliminary studies demonstrate that this method works very well and a pilot experiment using MGK has identified genes previously unknown to be involved in HNP-1 resistance. Based on this powerful method, we propose the following specific aims: (1) to identify genetic determinants of cationic 2-sheet HNP-1 resistance; (2) to identify genetic determinants of anionic dermcidin resistance; and (3) to characterize genes involved in HNP- 1 and dermcidin resistance. Successful accomplishing of this project will set the stage for in-depth understanding of mechanisms of bacterial resistance to antimicrobial peptides as planned in a follow-up RO1 project. Moreover, as bacterial pathogens defective in antimicrobial peptide resistance are attenuated in animal infections, a comprehensive list of resistance determinants may help understand their contribution to bacterial pathogenesis and may provide insights into new anti-infective strategies. Antimicrobial peptides are a promising class of new antibacterial therapies due to their potent bactericidal activity against bacteria resistant to conventional antibiotics, and they are now at various stages of clinical trials for systemic and topical use. Thus, the understanding of bacterial natural resistance to these peptides is important as a prerequisite to assessing potential emergence of bacteria highly resistant to them in clinical settings and possibly developing measures to overcome such resistance.

描述（由申请人提供）：抗菌肽是一类有希望的新抗菌剂，特别是由于它们对传统抗生素耐药性抗性细菌的有效活性。只有少数此类肽，例如多霉素，一直处于临床实践中，迄今为止，多粘蛋白是唯一一种抗多药耐药的革兰氏阴性细菌（例如铜绿假单胞菌）和苯甲酸杆菌的抗生素仍然很容易受到影响。现在，结构上与环状脂蛋白多肽在结构上有所不同的抗菌肽现在处于临床试验的各个阶段，例如全身性和局部药物，例如阳离子1螺旋pexiganan和2-呈2-酸膜。然而，最近的研究表明，在诊所中使用抗菌肽的使用最终将诱导高水平的细菌耐药性。在最坏的情况下，通常由人内源性抗菌肽控制的细菌可能会引起难以操纵的感染。我们在该项目中的目标是识别和表征细菌对人抗菌肽的遗传决定因素，例如阳离子2-呈2-地表嗜中性粒细胞肽-1（HNP-1）和阴离子皮质素-1，是评估对它们和克服这种抗药性的细菌抗性的潜在风险的先决条件。在革兰氏阴性病原体中，对这些类别的抗菌肽的抗性机制几乎是未知的。为了加快抗药性决定因素的发现，我们开发了一种新的基于微阵列的方法，即监测基因敲除（MGK）。 MGK可以同时分析培养物中成千上万种突变体的相对丰度。我们的初步研究表明，该方法效果很好，使用MGK的试点实验已经确定了以前未知的基因与HNP-1抗性有关。基于这种强大的方法，我们提出了以下特定目的：（1）识别阳离子2折叠HNP-1抗性的遗传决定因素； （2）确定阴离子皮肤素耐药的遗传决定因素； （3）表征涉及HNP-1和皮肤素耐药性的基因。成功完成该项目将为对抗菌肽的细菌耐药性机制的深入理解奠定阶段，如后续RO1项目中所计划的。此外，由于在动物感染中会减弱抗菌肽耐药性的细菌病原体，因此，全面的抗药性决定因素可能有助于了解其对细菌发病机理的贡献，并可能提供对新的抗感染策略的见解。 抗菌素肽是一类新的新抗菌疗法，因为它们的有效杀菌活性针对对常规抗生素的抗性细菌，现在它们处于用于系统性和局部使用的临床试验的各个阶段。因此，对细菌对这些肽的自然抗性的理解非常重要，这是评估细菌在临床环境中对它们高度抗药性的潜在出现的先决条件，并可能制定措施克服这种耐药性。