Biofilm细菌生物膜适用医学生.ppt

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1、细菌生物膜细菌生物膜内容适合医学院内容适合医学院3-5年级学生使用年级学生使用“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/逐渐生长逐渐生长/增加增加 that adhere to biological or non-biological surfaces.

2、on a contact lenson 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 pro

3、tected 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细菌生物膜广泛存在于自然环境中真菌生物膜Biofilms can be harmfulCatheters and prostheses(may lead to systemic infection)Dental disease（牙菌斑、口腔味道？）（牙菌斑、口腔味

4、道？）Otitis media/中耳炎中耳炎,inflammatory bowel disease/IBD,prostatitis/前列腺炎前列腺炎,sinusitis/鼻窦鼻窦炎炎,etc.生物膜与疾病（总结）生物膜与疾病（总结）细菌生物膜细菌生物膜进入体内的进入体内的可能途径可能途径细菌生物膜的基本性质细菌生物膜的基本性质生物膜生物膜1978年由年由J.William Costerton等通等通过电镜方法首次方法首次观察到察到 Biofilm定定义：指：指细菌自身菌自身产生的外部多糖基生的外部多糖基质、纤维蛋白蛋白质、脂蛋白等包裹着的菌、脂蛋白等包裹着的菌细胞的胞的结构。构。生物被膜是生物

5、被膜是细菌的一种具有保菌的一种具有保护性的生性的生长模式，是模式，是细胞胞间相互相互协调作用的复作用的复杂的多的多细胞群体，具有胞群体，具有结构和代构和代谢复复杂性。性。形成生物被膜的黏附形成生物被膜的黏附细菌群也可以菌群也可以释放出浮游放出浮游细菌，是潜菌，是潜在的持在的持续感染因素。感染因素。Biofilms matrix-enclosed microbial accretions/逐渐生长逐渐生长/增加增加 that adhere to biological or non-biological surfaces.古老：fossil record(3.25 billion years ag

6、o)Common：a diverse range of organismsArchaea/单细胞生物,bacteria，fungiRepresents a protected mode of growth that allows cells to survive in hostile environmentsCan disperse to colonize new niches/可以可以释放出浮游放出浮游细菌，生菌，生长迅速，是潜在感染因素迅速，是潜在感染因素Biofilm 特点总结特点总结Biofilm 的形成过程的形成过程-体内过程体内过程Biofilm 的形成过程的形成过程-从菌落角度从

7、菌落角度细菌的初始吸附与细菌的初始吸附与其鞭毛、菌毛有关其鞭毛、菌毛有关Nature Rev Micro 2010像像“铠甲铠甲”一样一样生物膜的结构特点生物膜的结构特点化学组成化学组成 水分（水分（97%97%）胞外大分子胞外大分子 吸附的吸附的营养物养物质及代及代谢产物、物、细菌裂解物菌裂解物 蛋白蛋白质、DNA 细菌生物膜的结构特点细菌生物膜的结构特点生物膜的结构特点生物膜的结构特点成熟生物被膜模型成熟生物被膜模型 由外到内依次为：由外到内依次为：生物被膜层（生物被膜层（bulk of biofilmbulk of biofilm）连接层（连接层（linking filmlinking

8、film）条件层（条件层（conditioning filmconditioning film）基质层（基质层（substratum)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满水通道,是细菌获取营养和排除代谢废物的通道。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 placeDifferent species,different biofilm

9、 developmentMixes of polysaccharides,proteins,and nucleic acids成分成分The Biofilm MatrixNat Rev Micro 2010成分成分原理原理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与抗性和特点细菌生物膜细菌生物膜进入体内的进入体内的可能途径可

10、能途径临床意义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 临床意义临床意义Apical periodontitis is a chronic inflammatory disorder of periradicular tissues caused by aetiological agent

11、s 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,inad

12、equate instrumentation,debridement and leaking temporary or permanent restorations.Even when the most stringent procedures are followed,apical periodontitis may still persist as asymptomatic radiolucencies/射线射线可透性可透性,because of the complexity of the root canal system formed by the main and accessory

13、 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与口腔的关系与口腔的关系Further,there are extraradicular factors located within the inflamed periapical tissue that can inter

14、fere 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)

15、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 h

16、ealing of the lesionHow are biofilms studied in the lab?Single-species vs.Multi-speciesTransparent flow cellsBacteria attach to glass and nutrients flow through the cellMicroscopyBacterial culture生物被膜的观察研究方法生物被膜的观察研究方法 扫描电镜:Costerton等人在70年代通过扫描电镜观察到了细菌的生物被膜的存在。激光共聚焦显微镜:分子生物学方法：Huth et al2008SEMcoccineutrophilbugThanksAdiosCiao谢谢谢谢Flush your teeth dailyBrush your teeth 3 times a day