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（由申请人提供）：金黄色葡萄球菌是一种高毒力且广泛成功的病原体，据推测是人类疾病的最常见原因。目前，它是全世界医院感染的主要病原体，在宿主体内的众多生态位中引起多种疾病。由于多重耐药菌株 (MRSA) 的不断出现，包括对最后手段糖肽抗生素 (VRSA) 耐药的菌株，金黄色葡萄球菌也是一个主要的公共卫生问题。除此之外，在过去的 10 年里，健康受试者中严重侵袭性金黄色葡萄球菌感染的病例急剧增加，而这些受试者缺乏任何诱发因素或与医疗机构的联系。显然，MRSA 的高毒力菌株（CA-MRSA）已在社区中进化，具有毒力因子和耐药性特征的独特组合。 CA-MRSA 菌株毒力和传播增强的原因尚不清楚；然而最近的研究表明，这可能是 agr 调节的毒素分泌过多的结果。其中包括细胞外蛋白酶，我们自己和其他人已经证明，与 HA-MRSA 分离株相比，CA-MRSA 菌株中的细胞外蛋白酶过量产生。尽管我们小组的报告证明了细胞外蛋白酶对疾病病因的贡献，但它们作为金黄色葡萄球菌感染的关键毒力决定因素的作用仍不清楚。因此，考虑到目前 CA-MRSA 感染的临床意义，以及这些菌株过度分泌细胞外蛋白酶的事实，我们建议明确探索这些酶对金黄色葡萄球菌发病机制的贡献。为了实现这一目标，我们将： 1. 研究细胞外蛋白酶在金黄色葡萄球菌生理学和毒力决定簇稳定性中的作用。这将通过以下方式进行： i) 生成主要 CA-MRSA 菌株 (USA300) 的衍生物，其中 4 个主要蛋白酶基因座均已被删除。然后，该菌株将用于： ii) 表型表征这些酶对金黄色葡萄球菌生长和生理学的体外贡献； iii) 使用蛋白质组学分析分泌蛋白质组和细胞壁蛋白质组的变化，探索外切蛋白酶对毒力决定簇稳定性的影响。在确定了体外细胞外蛋白酶的影响后，我们将使用我们的突变株来评估它们对体内毒力的贡献。为了实现这一目标，我们将： 2. 探索细胞外蛋白酶对 CA-MRSA 发病机制的影响。这将通过以下方式进行： i) 评估细胞外蛋白酶对金黄色葡萄球菌皮肤和软组织感染的贡献； ii) 使用败血症和传播的小鼠模型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且广泛成功的病原体，据推测是人类感染的最常见原因。随着多重耐药金黄色葡萄球菌分离株（例如 MRSA）的不断出现，迫切需要了解这种致命病原体引起疾病的机制。该提案旨在了解分泌蛋白酶对金黄色葡萄球菌疾病病因的贡献。

项目成果

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

CodY 对社区相关耐甲氧西林金黄色葡萄球菌毒力决定簇产生的影响。

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

NsaRS is a cell-envelope-stress-sensing two-component system of Staphylococcus aureus.

NsaRS 是金黄色葡萄球菌的细胞包膜应激感应双组分系统。

• 发表时间: 2011-08
• 作者: Kolar, Stacey L;Nagarajan, Vijayaraj;Oszmiana, Anna;Rivera, Frances E;Miller, Halie K;Davenport, Jessica E;Riordan, James T;Potempa, Jan;Barber, David S;Koziel, Joanna;Elasri, Mohamed O;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.

需要利用甘露醇来保护金黄色葡萄球菌免受人类皮肤抗菌脂肪酸的侵害。

• 发表时间: 2013
• 影响因子: 3.7
• 作者: Kenny, John G;Moran, Josephine;Kolar, Stacey L;Ulanov, Alexander;Li, Zhong;Shaw, Lindsey N;Josefsson, Elisabet;Horsburgh, Malcolm J
• 通讯作者: Horsburgh, Malcolm J

Galectin-3 Is a Target for Proteases Involved in the Virulence of Staphylococcus aureus.

Galectin-3 是参与金黄色葡萄球菌毒力的蛋白酶的靶标。

• 发表时间: 2017
• 影响因子: 3.1
• 作者: Elmwall, Jonas;Kwiecinski, Jakub;Na, Manli;Ali, Abukar Ahmed;Osla, Veronica;Shaw, Lindsey N;Wang, Wanzhong;Sävman, Karin;Josefsson, Elisabet;Bylund, Johan;Jin, Tao;Welin, Amanda;Karlsson, Anna
• 通讯作者: Karlsson, Anna