P. Aeruginosa Biofilms and Burn Wound Infections

铜绿假单胞菌生物膜和烧伤伤口感染

• 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
• 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
• 来源: https://reporter.nih.gov/project-details/7032449
• 关键词: Pseudomonas aeruginosa; antibiotics; bacterial genetics; biofilm; burns; flow cytometry; gene expression; gene expression profiling; green fluorescent proteins; liquid chromatography mass spectrometry; microarray technology; multidrug resistance; nosocomial infections; opportunistic infections; pathologic process; phenotype; protein structure function; proteomics; swine; virulence; wound healing; wound infection

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.

由多种抗生素耐药细菌引起的医院感染尤其难以治愈，造成重大健康风险，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，主要感染免疫受损的个体和严重烧伤创面的患者。尽管铜绿假单胞菌是院内感染的主要原因之一，但人们对体内生物膜表型和细菌因素知之甚少，这些因素可以阻止伤口愈合并促进铜绿假单胞菌在感染部位的持续存在。我们最近发现，铜绿假单胞菌生物膜与浮游生物相比表现出截然不同的表型，超过800种蛋白质和2000种基因在生物膜中差异表达。定义体外生物膜表型的毒力性状包括最近与伤口感染相关的ExoS-T、ExoA、LasB和OprF-I。使用猪烧伤模型，我们也证明了细菌形成基质包裹，抗微生物的微菌落。与未感染的伤口相比，铜绿假单胞菌感染伤口中蛋白表达的变化与伤口中铜绿假单胞菌生物膜的形成相关。有趣的是，蛋白质表达分析还显示，体内铜绿假单胞菌生物膜中的蛋白质表达增加，而这些蛋白质在体外生物膜中被抑制。在本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现有的生物膜模型，研究铜绿假单胞菌生物膜在烧伤创面感染中的作用，并确定铜绿假单胞菌体内生物膜表型。据我们所知，这是第一次尝试解决如此复杂的任务。我们的研究结果表明存在新颖和更多