1、雙語細菌的感染與免疫演示文稿第一頁，共六十七頁。雙語細菌的感染與免疫第二頁，共六十七頁。Bacterial Infection細菌的感染The process of bacteria invading in the body, growing in the tissues, producing toxins and causing diseases is called bacterial infection.第三頁，共六十七頁。Pathogen（病原菌）Pathogenic bacterium （致病菌）A bacterium which can cause a disease is call

2、ed pathogen. Nonpathogen（非病原菌）Nonpathogenic bacterium（非致病菌）A bacterium that does not cause disease is called nonpathogen.第四頁，共六十七頁。Opportunistic pathogen（機會致病菌）Conditioned pathogen（條件致病菌）Some bacteria are capable of causing diseases only under certain conditions.These organisms can cause disease onl

3、y if one or more of the usual defence mechanisms humans have evolved to restrict microorganisms from their usually sterile internal organs and tissue are breached by accident, by intent (e.g. surgery), or by an underlying metabolic or an infectious disorder (e.g. AIDS).第五頁，共六十七頁。OutlineNormal flora

4、and opportunistic pathogenBacterial pathogenesisThe host immune defence systemThe initiation and course of infectionHospital infection第六頁，共六十七頁。Section 1 Normal flora and opportunistic pathogen正常菌群與機會致病菌第七頁，共六十七頁。 Normal flora（正常菌群）Normal microbial flora（正常微生物群）The population of microorganisms that

5、inhabit the skin and mucous membranes of healthy persons. They are usually harmless, some even beneficial, to humans health.第八頁，共六十七頁。LocationsSurface tissues of skin Oral cavity Respiratory tractGastrointestinal tractGenitourinary tract第九頁，共六十七頁。Normal flora on intestinal mucosa第十頁，共六十七頁。腸道的正常菌群第十一

6、頁，共六十七頁。第十二頁，共六十七頁。 Beneficial effects of the normal floraBiological antagonism （生物拮抗）Production of essential nutrients（營養作用）Priming of immune system（免疫作用）Anti-aging（抗衰老作用）第十三頁，共六十七頁。Biological antagonism (生物拮抗)Biological barriers（生物屏障）or Receptor competition（受體競爭)Harmful metabolites（有害代謝產物）Nutrient

7、 competition（營養競爭）第十四頁，共六十七頁。Conditioned pathogen（條件致病菌）Some bacteria are capable of causing diseases only under certain conditions. These bacteria are called opportunistic (conditioned) pathogens and this kind of infection is called opportunistic infection（機會性感染）. Opportunistic pathogen（機會致病菌）第十五頁，

8、共六十七頁。 Conditions of opportunistic infectionChange of inhabiting places（寄居部位改變）Immune system compromise（宿主免疫功能低下）Dysbacteriosis（菌群失調）第十六頁，共六十七頁。Dysbacteriosis（菌群失調）If flora disequilibrium occurs, for example, when the resident flora is disturbed, some little significant microorganisms may colonize,

9、proliferate, and produce disease, which is called dysbacteriosis. Dysbacteriosis mainly resulted from long term and large doses antibiotics taken.第十七頁，共六十七頁。Superinfection（重疊感染）A frequent complication of drug therapy for microbial infection. It may result from opportunistic colonization following im

10、munosuppression by the primary pathogen and can be influenced by the time interval between infections, microbial physiology, or host resistance. 第十八頁，共六十七頁。Dysbacteriosis and superinfection第十九頁，共六十七頁。腸道的正常菌群健康青壯年糞便涂片健康老年糞便涂片（雙歧桿菌）第二十頁，共六十七頁。Probiotics（益生菌）第二十一頁，共六十七頁。Probiotics（益生菌）& Prebiotics（益生元）

11、第二十二頁，共六十七頁。Section 2 Bacterial Pathogenesis細菌的致病作用Basic termsBacterial Pathogenicity Bacterial virulenceNumber of invading organismsPortal of entry 第二十三頁，共六十七頁。Pathogenicity（致病性） is used to describe the capacity of bacteria to initiate diseases.The term of virulence（毒力） is used as a comparison of p

12、athogenicity in the quantitative sense.ID50（median infectious dose, 半數感染量）: Infectious dose of bacteria for 50% of the test population.LD50 （median lethal dose, 半數致死量） : Lethal dose of bacteria for 50% of the test population.Basic Terms第二十四頁，共六十七頁。ExotoxinPili (Fimbrial)CapsuleVirulent EnzymeAdhesin

13、sFlagellaIron bindingproteinVirulence surface proteinBacterial virulence factors（細菌毒力因子）第二十五頁，共六十七頁。Bacterial virulence（細菌的毒力）Virulence（毒力）Invasiveness（侵襲力）Toxin（毒素）Adherence & permanent planting（黏附與定植）Multiplication &diffusion （增殖與擴散）Anti-defense functionof host （免疫逃逸）Endotoxin（內毒素）Exotoxin（外毒素）第二十

14、六頁，共六十七頁。Adhesion and field planting（黏附與定植）Invasion（侵入）Multiplication and diffusion（繁殖與擴散）Local diffusion（局部擴散）Systemic diffusion（全身性擴散）第二十七頁，共六十七頁。 Invasiveness（侵襲力）Definition: Bacterial capability that can break through the physiologic barriers (skin, mucosa), settle down, multiply, and spread in

15、the host.Adhesive factors: adhesin and capsuleInvasive substancesBacterial biofilm第二十八頁，共六十七頁。1. Adhesin（黏附素）Protiens on bacterial surface associated with adhesion.Adhesins bind to adhesin receptors on host cells.Classification:Pilus (fimbriae) adhesin (菌毛黏附素)Non-fimbriae adhesin (非菌毛黏附素)第二十九頁，共六十七頁

16、。AdhesinAdhesinEpitheliumReceptorBacterium第三十頁，共六十七頁。Capsule (莢膜) of streptococcus pneumoniaeMicrocapsule（微莢膜） Slime layer（黏液層）第三十一頁，共六十七頁。Protect the cell wall against attack by drugs Inhibit ingestion and killing by phagocytesPlay a role in the adherence of human tissueAntigenicity2. Capsule（莢膜）第三

17、十二頁，共六十七頁。3. Invasive enzymes侵襲性酶類 Some bacteria may generate invasive enzymes, which can damage body tissues and promote the invasion and diffusion of the bacteria.第三十三頁，共六十七頁。4. Invasin侵襲素Encoded by invasive genes（侵襲基因）Mediate invading adjacent epithelial cells第三十四頁，共六十七頁。5. Bacterial biofilm細菌生物被

18、膜： The membraneous bacterial community composed of bacteria and the extracellular polymers secreted by bacteria after they adhere to the surface of living or nonliving materials.第三十五頁，共六十七頁。5. Bacterial biofilm細菌生物被膜Facilitates bacterial adhesionBaffles the penetration of antibiotic and the rejectio

19、n of immune systemProfits signal communication among bacteria.第三十六頁，共六十七頁。Bacterial biofilm第三十七頁，共六十七頁。第三十八頁，共六十七頁。 Biofilm in the endoscope（內窺鏡）第三十九頁，共六十七頁。Staphylococcus epidermidis（表皮葡萄球菌）biofilm in the surface of venous catheter（靜脈導管）第四十頁，共六十七頁。ExotoxinsEndotoxinsExcreted by living cells; high c

20、oncentrations in liquid medium.Integral part of the cell wall of G- bacteria. Released on bacterial death and in part during growth. May not need to be released to have biologic activity.Produced by both G+ and G- bacteria.Found only in G- bacteria.PolypeptidesLPS (lipid A portion probably responsib

21、le for toxicity.)Relatively unstable; toxicity often destroyed rapidly by heating at temperatures above 60.Relatively stable; withstand heating at temperatures above 60 for hours without loss of toxicity.第四十一頁，共六十七頁。ExotoxinsEndotoxinsHighly antigenic; stimulate formation of high-titer antitoxin (抗毒

22、素). Antitoxin neutralizes toxin.Weakly immunogenic; antibodies are antitoxic and protective. Relationship between antibody titers and protection from disease is less clear than with exotoxins.Converted to antigenic, nontoxic toxoids (類毒素) by formalin, acid, heat, etc. Toxoids are used to immunize.No

23、t converted to toxoids.Highly toxic; fatal to animals in microgram quantities or less.Moderately toxic; fatal for animals in tens to hundreds of micrograms.第四十二頁，共六十七頁。ExotoxinsEndotoxinsUsually bind to specific receptors on cells.Specific receptors not found on cells.Usually do not produce fever in

24、 the host. Selective toxicity and specific clinical syndromes. Neurotoxins (神經毒素) Cytotoxins (細胞毒素) Enterotoxins (腸毒素)Usually produce fever in the host by release of IL-1 and other mediators.Frequently controlled by extrachromosomal genes (e.g. plasmids).Synthesis directed by chromosomal genes.第四十三頁

25、，共六十七頁。區別要點外毒素內毒素來源革蘭陽性菌與部分革蘭陰性菌革蘭陰性菌編碼基因質粒、前噬菌體或染色體基因染色體基因存在部分從活菌分泌出，少數菌崩解后釋出細胞壁組分，菌裂解后釋出化學成分蛋白質脂多糖穩定性6080，30分鐘破壞160，24小時破壞毒性作用強，對組織器官有選擇性毒害效應，引起特殊的臨床表現較弱，各菌的毒性效應大致相同，引起發熱、白細胞增多、微循環障礙、休克、DIC等抗原性強，刺激機體產生抗毒素；甲醛液處理脫毒形成類毒素弱，刺激機體產生的中和抗體作用弱；甲醛液不能脫毒形成類毒素第四十四頁，共六十七頁。Specific polysaccharideLPS第四十五頁，共六十七頁。Pr

26、ocedure 第四十六頁，共六十七頁。Neurotoxin（神經毒素） Tetanus toxin（破傷風毒素）第四十七頁，共六十七頁。Cytotoxins（細胞毒素）Diphtheria toxin（白喉毒素）inhibits protein synthesis in mammalian cells and causes necrosis of cellsDiphtheria membrane on throat第四十八頁，共六十七頁。Enterotoxin（腸毒素） Cholera enterotoxin 第四十九頁，共六十七頁。Biological roles of endotoxin

27、Fever（發熱）Leukopenia and leukocytosis（白細胞反應 ）Endotoxemia and shock（內毒素血癥與休克）第五十頁，共六十七頁。EndotoxinActivatesmacrophagesActivatescomplementActivatesHageman factorIL-1 ,TNF, Nitric oxideFever and hypotensionC3a, C5a Hypotension EdemaCoagulation cascadeDIC第五十一頁，共六十七頁。Section 4 the initiation and process of

28、 infectionSources of infectionPathway of bacterial entranceTypes of bacterial infection第五十二頁，共六十七頁。Exogenous infection（外源性感染）PatientsCarriers（帶菌者）AnimalsEnodogenous infection（內源性感染）Opportunistic pathogens Sources of infection第五十三頁，共六十七頁。Pathway of pathogen entrance Respiratory Gastrointestinal Genit

29、al Skin and mucosa Animal bites Blood Sexual transmission第五十四頁，共六十七頁。Types of bacterial infectionInapparent infection（隱性感染）Apparent infection（顯性感染）Carrier state（帶菌狀態）第五十五頁，共六十七頁。Inapparent infection（隱性感染）Subclinical infection（亞臨床型感染）An infection that has no observable symptoms.It occurs when the hos

30、t immunity is potent or the pathogenicity of the pathogen is weak. 第五十六頁，共六十七頁。The tip of the iceberg 第五十七頁，共六十七頁。Apparent infection（顯性感染）Acute infectionChronic infectionLocal infectionGeneralized infection Toxemia (毒血癥)Endotoxemia (內毒素血癥)Bacteremia (菌血癥)Septicemia (敗血癥)Pyemia (膿毒血癥)第五十八頁，共六十七頁。Toxe

31、mia（毒血癥）Bacteria mutiply at invading location and do not enter blood stream, but the exotoxins（外毒素）enter blood and cause corresponding toxic symptoms.Endotoxemia（內毒素血癥）Gram-negative bacteria mutiply at location or in blood stream, release a lot of amount endotoxin（內毒素） released from bacterial cell r

32、upture.第五十九頁，共六十七頁。Bacteremia（菌血癥）After entering blood, bacteria circulate but not multiply in the blood.Septicemia（敗血癥）Bacteria circulate and multiply in the blood, in which bacteria produce toxic products and cause high swinging type of fever and other toxic symptoms.第六十頁，共六十七頁。Pyemia（膿毒血癥）Pyogenic（化膿性） bacteria produce septicemia with multiple abscesses（膿腫） in internal organs such as spleen , liver and kidneys.第六十一頁，共六十七頁。 Carrier state（帶菌狀態）After inapparent infection or apparent infection, sometimes the path