The Role of Extracellular Proteases in CA-MRSA Infections

细胞外蛋白酶在 CA-MRSA 感染中的作用

• 批准号: 8074918
• 负责人: Lindsey Neil Shaw
• 金额: $ 21.83万
• 依托单位: UNIVERSITY OF SOUTH FLORIDA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-01 至 2013-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8074918
• 关键词: Abscess; Antibiotic Resistance; Antibiotics; Benign; Blood; Cell Wall; Clinical; Communities; Complex; Disease; Endocarditis; Environment; Enzymes; Epidemiology; Etiology; Exopeptidase; Exotoxins; Furuncles; Genetic; Glycopeptide Antibiotics; Growth; Healthcare; Hemolysin; Human; In Vitro; Infection; Infectious Agent; Infectious Skin Diseases; Lead; Modeling; Multi-Drug Resistance; Mus; Nosocomial Infections; Pathogenesis; Peptide Hydrolases; Physiology; Pneumonia; Population; Predisposing Factor; Process; Proteome; Proteomics; Public Health; Reporting; Resistance; Resort; Role; Sepsis; Skin Tissue; Soft Tissue Infections; Staphylococcus aureus; Testing; Toxin; Vancomycin; Vancomycin-resistant S. aureus; Virulence; Virulence Factors; Virulent; Work; clinically significant; extracellular; human disease; human morbidity; human mortality; in vivo; mutant; pathogen; public health relevance; success; trait; transmission process; wound

DESCRIPTION (provided by applicant): Staphylococcus aureus is a highly virulent and widely successful pathogen, which is speculated to be the most common cause of human disease. Currently, it is the leading agent of nosocomial infections worldwide, causing a variety of ailments in a plethora of ecological niches within the host. S. aureus is also a major public health concern due to the continued emergence of multi-drug resistant isolates (MRSA), including those resistant to last resort glycopeptide antibiotics (VRSA). In addition to this, over the last 10 years, there has been a disturbing and meteoric increase in cases of severe invasive S. aureus infections in healthy subjects, lacking any predisposing factors or connections to healthcare settings. Apparently, hypervirulent strains of MRSA have evolved in the community (CA-MRSA), possessing unique combinations of virulence factors and resistance traits. The reason for the enhanced virulence and transmission of CA-MRSA strains is unclear; however recent work suggests that it may be the result of hypersecretion of agr regulated toxins. Included amongst these are extracellular proteases, which ourselves and others have shown to be overproduced in CA-MRSA strains compared to HA-MRSA isolates. Despite reports by our group demonstrating the contribution of extracellular proteases to disease causation, their role as key virulence determinants in S. aureus infections is still unclear. Therefore, given the current clinical significance of CA-MRSA infections, and the fact that these strains hyper secrete extracellular proteases, we propose to definitively explore the contribution of these enzymes to S. aureus pathogenesis. To achieve this we will: 1. Investigate the role of extracellular proteases in S. aureus physiology and virulence determinant stability. This will be carried out by: i) Generating a derivative of the leading CA-MRSA strain (USA300) in which each of the 4 major protease loci has been deleted. This strain will then be use to: ii) Phenotypically characterize the in vitro contribution of these enzymes to S. aureus growth and physiology; and iii) Explore the effect of exoproteases on virulence determinant stability using proteomics to analyze alterations in secreted and cell wall proteomes. Having determined the impact of the extracellular proteases in vitro we will then use our mutant strain to assess their contribution to virulence in vivo. To achieve this we will: 2. Explore the impact of extracellular proteases on CA-MRSA pathogenesis. This will be carried out by: i) Assessing the contribution of extracellular proteases to S. aureus skin and soft tissue infections; and ii) Exploring the role of these enzymes in severe invasive disease using a murine model of sepsis and dissemination. PUBLIC HEALTH RELEVANCE: Staphylococcus aureus is a highly virulent and widely successful pathogen that is speculated to be the most common cause of human infection. With the continued emergence of multi-drug resistant isolates of S. aureus (such as MRSA), there is an urgent need to understand the mechanisms by which this deadly pathogen causes disease. This proposal seeks to understand the contribution of secreted proteases to S. aureus disease causation.

描述(申请人提供)：金黄色葡萄球菌是一种高毒力和广泛成功的病原体，被认为是人类疾病最常见的原因。目前，它是世界范围内医院感染的主要病原体，在宿主内过多的生态位中导致各种疾病。金黄色葡萄球菌也是一个主要的公共卫生问题，因为多重耐药菌株(MRSA)的持续出现，包括那些对最后使用的糖肽抗生素(VRSA)耐药的菌株。除此之外，在过去的10年里，由于缺乏任何诱因或与医疗保健环境的联系，健康受试者中严重侵袭性金黄色葡萄球菌感染的病例迅速增加，令人不安。显然，超强毒力的MRSA菌株已经在群落中进化(CA-MRSA)，具有毒力因子和抗性特征的独特组合。CA-MRSA菌株毒力增强和传播的原因尚不清楚，但最近的研究表明，这可能是agr调节毒素过度分泌的结果。其中包括胞外蛋白酶，我们和其他人已经证明，与HA-MRSA分离株相比，CA-MRSA菌株中的胞外蛋白水解酶产量过高。尽管我们小组的报告证明了胞外蛋白酶在疾病病因中的作用，但它们在金黄色葡萄球菌感染中作为关键毒力决定因素的作用仍不清楚。因此，鉴于目前CA-MRSA感染的临床意义，以及这些菌株高分泌胞外蛋白水解酶的事实，我们建议明确地探讨这些酶在金黄色葡萄球菌致病中的作用。为了实现这一目标，我们将：1.研究胞外蛋白水解酶在金黄色葡萄球菌生理和毒力决定簇稳定性中的作用。这将通过以下步骤实现：i)产生主要的CA-MRSA菌株(USA300)的衍生物，其中4个主要的蛋白水解酶基因座中的每一个都已被删除。该菌株将被用于：ii)这些酶在体外对金黄色葡萄球菌生长和生理的贡献的表型特征；以及iii)利用蛋白质组学来分析分泌和细胞壁蛋白质组的变化，探索外源蛋白酶对毒力决定簇稳定性的影响。在体外确定了胞外蛋白水解酶的影响后，我们将使用我们的突变株来评估它们对体内毒力的贡献。为此，我们将：2.探讨胞外蛋白水解酶在CA-MRSA发病机制中的作用。这将通过以下方式进行：i)评估细胞外蛋白水解酶在金黄色葡萄球菌皮肤和软组织感染中的作用；ii)使用脓毒症和播散的小鼠模型来探索这些酶在严重侵袭性疾病中的作用。 公共卫生相关性：金黄色葡萄球菌是一种高毒力和广泛成功的病原体，被认为是人类感染的最常见原因。随着金黄色葡萄球菌多重耐药菌株的不断出现(如MRSA)，迫切需要了解这种致命病原体致病的机制。这项建议试图了解分泌性蛋白酶在金黄色葡萄球菌疾病病因中的作用。

项目成果

The impact of CodY on virulence determinant production in community-associated methicillin-resistant Staphylococcus aureus.

• DOI: 10.1002/pmic.201100298
• 发表时间: 2012-01
• 期刊: PROTEOMICS
• 影响因子: 3.4
• 作者: Rivera, Frances E.;Miller, Halie K.;Kolar, Stacey L.;Stevens, Stanley M., Jr.;Shaw, Lindsey N.
• 通讯作者: Shaw, Lindsey N.

Mannitol utilisation is required for protection of Staphylococcus aureus from human skin antimicrobial fatty acids.

保护金黄色葡萄球菌免受人体皮肤抗菌脂肪酸的保护需要甘露醇利用。

• DOI: 10.1371/journal.pone.0067698
• 发表时间: 2013
• 期刊: PloS one
• 影响因子: 3.7
• 作者: Kenny JG;Moran J;Kolar SL;Ulanov A;Li Z;Shaw LN;Josefsson E;Horsburgh MJ
• 通讯作者: Horsburgh MJ