Biofilm细菌生物膜适用医学生.ppt

细菌生物膜,内容适合医学院3-5年级学生使用,“In a paper in Science in 1999, we said 65 percent of all diseases in the developed world are biofilms,” Costerton said. “Now the NIH says 80 percent. ”,Biofilms matrix-enclosed microbial accretions/逐渐生长/增加 that adhere to biological or non-biological surfaces.,on a contact lens,on a spider,细菌生物膜广泛存在于自然环境中,细菌生物膜广泛存在于自然环境中 Biofilm formation appears early in the fossil record (3.25 billion years ago) and is common throughout a diverse range of organisms in both the Archaea/ 单细胞生物 and Bacteria lineages. Biofilm formation represents a protected mode of growth that allows cells to survive in hostile environments and also disperse to colonize new niches.,回肠表面的细菌生物被膜,人体植入导管表面的细菌生物被膜,细菌生物膜广泛存在于自然环境中,真菌生物膜,Biofilms can be harmful Catheters and prostheses (may lead to systemic infection) Dental disease （牙菌斑、口腔味道？） Otitis media/中耳炎, inflammatory bowel disease/IBD, prostatitis/前列腺炎, sinusitis/鼻窦炎, etc.,生物膜与疾病（总结）,细菌生物膜进入体内的可能途径,细菌生物膜的基本性质,生物膜1978年由J. William Costerton等通过电镜方法首次观察到 Biofilm定义：指细菌自身产生的外部多糖基质、纤维蛋白质、脂蛋白等包裹着的菌细胞的结构。 生物被膜是细菌的一种具有保护性的生长模式，是细胞间相互协调作用的复杂的多细胞群体，具有结构和代谢复杂性。 形成生物被膜的黏附细菌群也可以释放出浮游细菌，是潜在的持续感染因素。,Biofilms matrix-enclosed microbial accretions/逐渐生长/增加 that adhere to biological or non-biological surfaces. 古老：fossil record (3.25 billion years ago) Common：a diverse range of organisms Archaea/ 单细胞生物, bacteria，fungi Represents a protected mode of growth that allows cells to survive in hostile environments Can disperse to colonize new niches/ 可以释放出浮游细菌，生长迅速，是潜在感染因素,Biofilm 特点总结,Biofilm 的形成过程- 体内过程,Biofilm 的形成过程- 从菌落角度,细菌的初始吸附与其鞭毛、菌毛有关,Nature Rev Micro 2010,像“铠甲”一样,生物膜的结构特点,化学组成 水分（97%） 胞外大分子 吸附的营养物质及代谢产物、细菌裂解物 蛋白质、DNA,细菌生物膜的结构特点,生物膜的结构特点 成熟生物被膜模型 由外到内依次为： 生物被膜层（bulk of biofilm） 连接层（linking film） 条件层（conditioning film） 基质层（substratum) 细菌被大量的胞外多糖包绕形成微菌落，各微菌落之间充满水通道,是细菌获取营养和排除代谢废物的通道。,All biofilms have a matrix (EPS) to protect against the environment and hold colonies in place Different species, different biofilm development Mixes of polysaccharides, proteins, and nucleic acids,成分,The Biofilm Matrix,Nat Rev Micro 2010,成分,原理,1、EPS的存在可以阻止抗生素作用- 细菌耐药性； 2、抗免疫清除：屏蔽作用使吞噬细胞和杀伤细胞及其所分泌的酶不能发挥作用； 3、细菌生活微环境改变：比如厌氧菌繁殖、H2S产生、pH改变（口臭、龋齿等） 4、Quorum sensing：参阅 , by Bonnie Basler (普林斯顿大学),细菌生物膜与抗性和特点,细菌生物膜进入体内的可能途径,临床意义,医疗器械表面、插入导管、植入医疗器具/hip replacement- 是医原性感染的主要原因之一 生物造成细菌对抗生素不敏感/耐药性 P. N. R. Nair (2006) International Endodontic Journal. On the causes of persistent apical periodontitis: a review,临床意义,Apical periodontitis is a chronic inflammatory disorder of periradicular tissues caused by aetiological agents of endodontic origin. Persistent apical periodontitis occurs when root canal treatment of apical periodontitis has not adequately eliminated intraradicular infection. Problems that lead to persistent apical periodontitis include: inadequate aseptic control, poor access cavity design, missed canals, inadequate instrumentation, debridement and leaking temporary or permanent restorations. Even when the most stringent procedures are followed, apical periodontitis may still persist as asymptomatic radiolucencies/ 射线可透性, because of the complexity of the root canal system formed by the main and accessory canals, their ramifications and anastomoses where residual infection can persist.,P. N. R. Nair (2006) International Endodontic Journal. On the causes of persistent apical periodontitis: a review,与口腔的关系,Further, there are extraradicular factors located within the inflamed periapical tissue that can interfere with post-treatment healing of apical periodontitis. The causes have not been well characterized, but there are six biological factors that lead to asymptomatic radiolucencies persisting after root canal treatment. (i) intraradicular infection persisting in the complex apical root canal system; (ii) extraradicular infection, generally in the form of periapical actinomycosis; (iii) extruded root canal filling or other exogenous materials that cause a foreign body reaction; (iv) accumulation of endogenous cholesterol crystals that irritate periapical tissues; (v) true cystic lesions, and (vi) scar tissue healing of the lesion,How are biofilms studied in the lab?,Single-species vs. Multi-species Transparent flow cells Bacteria attach to glass and nutrients flow through the cell Microscopy Bacterial culture,生物被膜的观察研究方法