Anti-MRSA activity of a Bacillus pumilus natural isolate

短小芽孢杆菌天然分离物的抗 MRSA 活性

• 批准号: 7571733
• 负责人: MICHIKO M NAKANO
• 金额: $ 22.4万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7571733
• 关键词: Alberta province; Anabolism; Anti-Bacterial Agents; Antibiotic Resistance; Antibiotics; Athletic; Bacillus (bacterium); Bacillus subtilis; Backcrossings; Bacteremia; Bacteria; Base Sequence; Blast Cell; Cause of Death; Cessation of life; Characteristics; Chemicals; Collaborations; Communicable Diseases; Communities; Competence; DNA; Data; Development; Disease Outbreaks; Endocarditis; Escherichia coli; Exhibits; Future; Gene Expression Profile; Genes; Genetic; Genome; Goals; Gram-Positive Bacteria; Healthcare; High Pressure Liquid Chromatography; Hospitals; Human; Individual; Infection; Infectious Skin Diseases; Libraries; Mediating; Meningitis; Methods; Modeling; Molecular Weight; Mutagenesis; Mutate; Mutation; Names; National Institute of Allergy and Infectious Disease; Oregon; Parents; Persons; Pharmaceutical Preparations; Plasmids; Pneumonia; Population; Prevalence; Production; Protons; Public Health; Regulation; Regulator Genes; Reporting; Research; Resistance; Resort; Risk Factors; Rivers; Scanning; Schools; Sequence Analysis; Staphylococcus aureus; Streptococcus pyogenes; Structure; Surface; System; Testing; Toxic Shock Syndrome; United States; Universities; Ursidae Family; Vancomycin; Vancomycin Resistance; antimicrobial; antimicrobial drug; bactericide; base; combat; community setting; gene function; genome sequencing; methicillin resistant Staphylococcus aureus; mutant; novel; pathogen; pathogenic bacteria; public health relevance; research study; resistant strain; tandem mass spectrometry

DESCRIPTION (provided by applicant): Infectious diseases are one of the leading causes of death worldwide. Emergence of antibiotic resistant bacteria causes serious concerns even for infections that once were treatable with antibiotics or other antimicrobial agents. A notable example is a recent outbreak of infections with methicillin resistant Staphylococcus aureus (MRSA). S. aureus infections were nosocomial and mostly confined to predisposed individuals. Originally, MRSA strains were found only in health care settings (HA-MRSA); however, more recently MRSA strains appear in the community (CA-MRSA) among individuals who bear no risk factor for the infections. In addition, increasing numbers of severe invasive infections with MRSA have been reported, which have resulted in and estimated 18,650 deaths during 2005 in the United States. Although vancomycin remains the last resort for treating MRSA infections, vancomycin resistant strains have begun to emerge among HA- and CA-MRSA isolates, necessitating the development of new strategies to combat MRSA infections. The antimicrobial substance C9ASA was identified from a natural isolate C9 of Bacillus pumilus. C9ASA is effective against some Gram-positive bacteria and exhibits the highest activity against S. aureus, including HA- and CA-MRSA, as well as Streptococcus pyogenes, a group A Streptococcus. Both S. aureus and group A Streptococcus are among the NIAID list of re-emerging pathogens. C9ASA is not produced by seven other B. pumilus strains thus far tested and is different from antibacterial substances that were previously isolated and reported from B. pumilus, suggesting that it is a novel compound. The long-term objectives of the proposed research are to develop a new drug to treat infections caused by MRSA and group A Streptococcus, and by using C9ASA and S. aureus as a model, to elucidate the mechanism by which Gram-positive pathogenic bacteria become resistant to certain antimicrobial agents. In Specific Aim 1, partially purified C9ASA will be further purified using HPLC and the molecular weight will be determined using tandem mass spectrometry. Proton NMR and multidimensional NMR will be applied to solve the structure of C9ASA. In Specific Aim 2, the mode-of-action of C9ASA will be determined by isolating and characterizing S. aureus mutants that are resistant to the substance. In addition, transcriptome analysis will be carried out to identify genes in S. aureus induced by C9ASA, which might uncover potential C9ASA targets. In Specific Aim 3, a genetic system for study of B. pumilus will be developed in order to facilitate experiments proposed in Specific Aim 4. Based on the hypothesis that B. pumilus lacks natural competence due to the absence of comS, a gene essential for B. subtilis competence, the comS gene will be introduced into B. pumilus C9 using a recently developed conjugative system to endow the C9 strain with natural competence. In Specific Aim 4, genes required for C9ASA production will be identified using mini-Tn10 mutagenesis. These genes likely include biosynthesis genes and regulatory genes involved in C9ASA production. PUBLIC HEALTH RELEVANCE: Invasive MRSA infections are a serious threat to public health worldwide. This proposal describes studies aimed at characterizing what might be a promising anti-MRSA substance for combating this re-emerging infectious threat.

描述（由申请人提供）：传染病是全球主要的死亡原因之一。抗生素耐药性细菌的出现引起了严重的关注，即使是曾经可以用抗生素或其他抗菌剂治疗的感染。一个值得注意的例子是最近爆发的耐甲氧西林金黄色葡萄球菌（MRSA）感染。S.金黄色葡萄球菌感染是医院感染，并且大多局限于易感个体。最初，MRSA菌株仅在卫生保健环境中发现（HA-MRSA）;然而，最近MRSA菌株出现在社区（CA-MRSA）中没有感染风险因素的个体中。此外，据报道，耐甲氧西林金黄色葡萄球菌严重侵入性感染的数量不断增加，估计2005年美国有18，650人死亡。尽管万古霉素仍然是治疗MRSA感染的最后手段，但万古霉素耐药菌株已开始在HA-和CA-MRSA分离株中出现，因此需要开发新的策略来对抗MRSA感染。从短小芽孢杆菌的天然分离物C9中鉴定出抗菌物质C9 ASA。C9 ASA对一些革兰氏阳性菌有效，对S.金黄色葡萄球菌，包括HA-和CA-MRSA，以及化脓性链球菌，A组链球菌。两个S。金黄色葡萄球菌和A组链球菌属于NIAID重新出现的病原体名单。C9 ASA不是由其他七个B生产的。pumilus菌株，并且不同于先前从B分离和报道的抗菌物质。pumilus，这表明它是一个新的化合物。拟议研究的长期目标是开发一种新药来治疗由MRSA和A组链球菌引起的感染，并使用C9 ASA和S.金黄色葡萄球菌作为模型，以阐明革兰氏阳性致病菌对某些抗菌剂产生耐药性的机制。在具体目标1中，将使用HPLC进一步纯化部分纯化的C9 ASA，并使用串联质谱法测定分子量。采用质子核磁共振和多维核磁共振技术解析C9 ASA的结构。在具体目标2中，C9 ASA的作用模式将通过分离和表征S来确定。金黄色葡萄球菌突变体对该物质具有抗性。此外，还将进行转录组分析以鉴定S.金黄色葡萄球菌诱导的C9 ASA，这可能揭示潜在的C9 ASA靶点。在具体目标3中，用于研究B的遗传系统。将开发pumilus，以促进具体目标4中提出的实验。基于假设B. pumilus由于缺少comS（B所必需的基因）而缺乏天然感受态。将comS基因导入B。pumilus C9菌株，利用新近开发的接合系统赋予C9菌株天然感受态。在特定目标4中，将使用mini-Tn 10诱变鉴定C9 ASA生产所需的基因。这些基因可能包括参与C9 ASA产生的生物合成基因和调控基因。公共卫生相关性：侵袭性MRSA感染是对全球公共卫生的严重威胁。该提案描述了旨在表征可能是一种有前途的抗MRSA物质以对抗这种重新出现的感染威胁的研究。