P. Aeruginosa Biofilms and Burn Wound Infections

铜绿假单胞菌生物膜和烧伤伤口感染

基本信息

批准号：
7032449
负责人：
Karin Sauer
金额：
$ 16.21万
依托单位：
STATE UNIVERSITY OF NY,BINGHAMTON
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-04-01 至 2007-09-30
项目状态：
已结题

项目摘要

Nosocomial infections by multiple antibiotic resistant bacteria are especially difficult to cure, pose a significant health risk and place an enormous burden on the economy. A leading cause of such nosocomial infections is the biofilm-forming Pseudomonas aeruginosa that primarily infects immune compromised individuals and those with severe burn wounds. In spite of P. aeruginosa being among the leading cause of nosocomial infections, little is known about the in vivo biofilm phenotype and the bacterial factors that prevent wound healing and promote persistence of P. aeruginosa at the infection site. We recently discovered that P. aeruginosa biofilms display a profoundly different phenotype compared to their planktonic counterparts with more than 800 proteins and 2000 genes being differentially expressed in biofilms. Among the virulence traits that defined the in vitro biofilm phenotype were ExoS-T, ExoA, LasB, and OprF-I that have recently been correlated with wound infections. Using a porcine burn wound model, we also demonstrated that bacteria formed matrix-encased, antimicrobial resistant microcolonies. The formation of P. aeruginosa biofilms in wounds correlated with a change in protein expression in P. aeruginosa-infected wounds as compared to non-infected wounds. Interestingly, the protein expression analysis also revealed an increased expression of proteins in in vivo P. aeruginosa biofilms that were found to be repressed in biofilms in vitro. In this R21 proposal, we intend to challenge current biofilm models by using emerging technologies and bold and aggressive approaches to investigate the role of P. aeruginosa biofilms in burn wound infections and to determine the P. aeruginosa in vivo biofilm phenotype. To our knowledge, this is the first attempt to tackle such a complex task. Our findings indicate the presence of novel and more virulent in vivo biofilm phenotypes in wounds. We hypothesize that biofilm formation correlates with clinical signs of infections and that in vivo P. aeruginosa biofilms display a new and more virulent phenotype than in vitro biofilms. To test our hypotheses, we propose to characterize the temporal formation of matrix-encased, antimicrobial resistant P. aeruginosa biofilms using an in vivo infection-biofilm model and to correlate our findings with signs of wound infections. We also propose to characterize the in vivo P. aeruginosa biofilm phenotype that is only displayed when normal microflora, and immunological and inflammatory cells are present. We anticipate that our findings will impact current treatment strategies to eradicate Pseudomonas biofilm infections by improving our understanding of P. aeruginosa pathogenesis and by identifying virulence factors that may be targeted for therapeutic intervention.

多种抗生素耐药细菌的医院感染特别难以治愈，构成重大的健康风险并给经济带来巨大负担。这种医院感染的主要原因是形成生物膜的铜绿假单胞菌，该假单胞菌主要感染免疫受损的个体和严重烧伤的人。尽管铜绿假单胞菌是医院感染的主要原因之一，但对体内生物膜表型和细菌因子的了解鲜为人知，这些细菌因素可防止伤口愈合并促进感染部位的铜绿假单胞菌的持久性。我们最近发现，与它们的浮游物质对应物相比，铜绿假单胞菌生物膜表现出明显不同的表型，其中800多种蛋白质和2000个基因在生物膜中差异表达。在定义体外生物膜表型的毒力性状中，最近与伤口感染相关的EXOS-T，EXOA，LASB和OPRF-I。使用猪烧伤模型，我们还证明了细菌形成基于基质的抗菌抗性微菌落。与未感染的伤口相比，伤口中铜绿假单胞菌生物膜的形成与铜绿假单胞菌感染的伤口的蛋白质表达的变化有关。有趣的是，蛋白质表达分析还表明，在体外被发现在体外被抑制的体内铜绿假单胞菌生物膜中蛋白质的表达增加。在此R21提案中，我们打算通过使用新兴技术和大胆而积极的方法来挑战当前的生物膜模型，以研究铜绿假单胞菌生物膜在烧伤伤口感染中的作用，并确定体内生物膜表型的铜绿假单胞菌。据我们所知，这是解决如此复杂的任务的第一次尝试。我们的发现表明了小说的存在以及更多伤口中的体内生物膜表型。我们假设生物膜的形成与感染的临床迹象相关，并且在体内铜绿假单胞菌生物膜比体外生物膜显示出一种新的，更具毒性的表型。为了检验我们的假设，我们建议使用体内感染 - 生物胶体模型来表征基于基质感染的，抗菌性铜绿假单胞菌生物膜的时间形成，并将我们的发现与伤口感染的迹象相关。我们还建议表征体内铜绿假单胞菌生物膜表型，仅在存在正常的菌群以及免疫学和炎症细胞。我们预计，我们的发现将影响当前的治疗策略，以通过提高我们对铜绿假单胞菌发病机理的理解并确定可能针对治疗性干预的毒力因子来消除假单胞菌生物膜感染。