Biofilm Infections in Postsurgical, Trauma, and Critically Ill Patients

描述（由申请人提供）：生物膜是在表面上生长并被由蛋白质、糖蛋白、糖脂、多糖和DNA组成的复杂细胞外聚合物物质包围的细菌群体。越来越多的人认识到，生物膜参与了大多数感染性疾病，特别是那些在手术后，创伤和危重病人。这些疾病包括通气患者的肺炎、心内膜炎、烧伤伤口感染和留置器械感染。术后、创伤和危重患者发生导管相关感染和手术部位感染的风险增加。医院感染是美国十大死亡原因之一，超过20%的医院感染是手术部位感染，其中很大一部分涉及手术缝合。血管导管是血流感染的最常见原因，据估计，每年发生250，000例导管相关血流感染，具有高归因死亡率（12%至25%）和3亿美元至数十亿美元的年度成本。该提案重点关注两种最常见的导管相关和手术部位感染病原体，即金黄色葡萄球菌和粪肠球菌。这些细菌不仅在生物膜相关感染中普遍存在，与葡萄球菌和肠球菌相关的抗菌素耐药性也在持续增加，因此发现预防这些感染的新策略变得越来越重要。这一建议背后的力量是我们最近发现的不寻常的（迄今未被识别），大细胞元素，出现在生物膜形成的早期（15分钟内），可能是至关重要的。我们有令人信服的初步证据表明，这些大的细胞元素可能不仅在生物膜与基质（表面）的初始附着中发挥关键作用，因此可能代表生物膜起始中的常见开关，但这些相对较大的细胞可能是被认为主要负责增加生物膜的抗生素耐药性的推定持久细胞。我们有四个具体目标。目的1将描述在生物膜发育早期出现的新发现的大细胞成分。目的2比较S. aureus和E.在缝线和硅橡胶导管材料上体外培养粪菌生物膜，重点关注早期发展。目的3将阐明新发现的大细胞成分在初始生物膜形成和抗生素敏感性中的作用。目的4将描述从术后、创伤和危重患者体内取出的废弃体内血管导管内的赘生物，并将这些数据与体外培养的生物膜赘生物进行比较。实验方法包括标准微生物学方法、共聚焦显微镜和高分辨率电子显微镜、细胞分选、荧光原位杂交和生化分析。所得数据将显著有助于我们理解生物膜感染的发生和治疗，特别是与术后、创伤和危重患者相关的生物膜感染。

DESCRIPTION (provided by applicant): A biofilm is a population of bacteria growing on a surface and surrounded by a complex extracellular polymeric substance composed of proteins, glycoproteins, glycolipids, polysaccharides, and DNA. There is increasing awareness that biofilms are involved in the majority of infectious diseases, especially those in postsurgical, trauma, and critically ill patients. These diseases include pneumonia in ventilated patients, endocarditis, burn wound infections, and infections of indwelling devices. Postsurgical, trauma, and critically ill patients are at increased risk for catheter-related infections and surgical site infections. Nosocomial infections are among the ten leading causes of death in the USA, and more than 20% of nosocomial infections are surgical site infections and a large proportion of these involve surgical suture. Vascular catheters are the most common cause of bloodstream infections and it is estimated that 250,000 catheter-associated bloodstream infections occur annually with high attributable mortality (12 to 25%) and annual costs ranging from $300 million to several billion dollars. This proposal focuses on two of the most prevalent etiologic agents of catheter-related and surgical site infections, namely Staphylococcus aureus and Enterococcus faecalis. Not only are these bacteria prevalent in biofilm-related infections, the antimicrobial resistance associated with staphylococci and enterococci continues to increase making it increasingly important to discover new strategies to prevent these infections. The force behind this proposal is our recent discovery of unusual (heretofore unrecognized), large cellular elements that appear early in biofilm formation (within 15 min) and are likely of critical importance. We have compelling preliminary evidence that these large cellular elements may not only play a pivotal role in initial attachment of the biofilm to the substratum (the surface) and may thus represent a common on-off switch in biofilm initiation, but these relatively large cells may be the putative persister cells thought to be primarily responsible for the increased antibiotic resistance of the biofilm. We have four specific aims. Aim 1 will characterize the large, newly discovered cellular elements that appear early in biofilm development. Aim 2 will compare the development and composition of S. aureus and E. faecalis biofilms cultivated in vitro on suture and on silastic catheter material, focusing on early developments. Aim 3 will clarify the role of the large, newly discovered cellular elements in initial biofilm development and in antibiotic susceptibility. Aim 4 will characterize the vegetations within discarded in vivo vascular catheters removed from postsurgical, trauma, and critically ill patients, and compare these data with biofilm vegetations cultivated in vitro. Experimental methods include standard microbiological methods, confocal microscopy and high resolution electron microscopy, cell sorting, fluorescence in situ hybridization, and biochemical analyses. Resulting data will significantly contribute to our understanding of the initiation and treatment of biofilm infections, especially those associated with postsurgical, trauma, and critically ill patients.