人卫7版微生物chapter7-细菌的感染与免疫.ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,Chapter 7 Bacterial Infection and immunity,Basic terms,Bacterial infection（细菌的感染）,Pathogen（病原菌）,Nonpathogen（非病原菌）,Opportunistic pathogen（机会致病菌）,Bacterial Infection,细菌的感染,The process of bacteria invading in the body,growing in the tissues,producing toxins and causing diseases is called bacterial infection.,Pathogen,（病原菌）,Pathogenic bacterium,（致病菌）,The bacterium which can cause a disease is called pathogen.,Nonpathogen,（非病原菌）,Nonpathogenic,bacterium,（非致病菌）,A bacterium that does not cause disease is called,nonpathogen,.,Opportunistic pathogen,（机会致病菌）,Conditioned pathogen,（条件致病菌）,Some bacteria are capable of causing diseases,only under certain conditions.,These organisms can cause disease only 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).,Outline,Normal flora and opportunistic,p,athogen,Bacterial pathogenesis,The host immune defence system,The initiation and course of infection,Hospital infection,Locations,Surface tissues of skinOral cavity,Respiratory tract,Gastrointestinal tract,Genitourinary tract,Normal flora on intestinal mucosa,肠道的正常菌群,Prime of life,Senium,Beneficial effects of the normal flora,Biological antagonism,（生物拮抗）,Production of essential nutrients,（营养作用）,Priming of immune system,（免疫作用）,Anti-aging,（抗衰老作用）,Anti-tumor,（抗肿瘤作用）,Biological antagonism(生物拮抗),Biological barriers（生物屏障）,Receptor competition,（受体竞争）,Harmful metabolites,（有害代谢产物）,Nutrient competition,（营养竞争）,Conditioned pathogen,（条件致病菌）,Some bacteria are capable of causing diseases only,under certain conditions,.These bacteria are called opportunisticconditioned)pathogens and this kind of infection is called,opportunistic infection,（机会性感染）.,Opportunistic pathogen,（机会致病菌）,Conditions of opportunistic infection,Change of inhabiting places,（寄居部位改变）,Immune system compromise,（,宿主免疫功能低下）,Dysbacteriosis,（菌群失调）,Dysbacteriosis（菌群失调）,If flora disequilibrium occurs,for example,when the resident flora is disturbed,some little significant microorganisms may colonize,proliferate,and produce disease,which is called,dysbacteriosis,.,Dysbacteriosis,mainly resulted from long term and large dose antibiotics taken.,Superinfection（重叠感染）,A frequent complication of drug therapy for microbial infection.,It may result from opportunistic colonization following immunosuppression by the primary pathogen and can be influenced by the time interval between infections,microbial physiology,or host resistance.,Dysbacteriosis and superinfection,肠道的正常菌群,健康青壮年,粪便涂片,健康老年粪便涂片,（双歧杆菌）,Probiotics（益生菌）,Probiotics（益生菌）&Prebiotics（益生元）,Section 2 Bacterial Pathogenesis,Basic term,Bacterial Pathogenicity,Bacterial virulence,Number of invading organisms,Portal of entry,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 pathogenicity in the quantitative sense.,ID,50,（median infectious dose,半数感染量）:,I,nfectious,d,ose of bacteria for 50%of the test population.,LD,50,（median lethal dose,半数致死量）,:,L,ethal,d,ose of bacteria for 50%of the test population.,Basic Term,Exotoxin,Pili(Fimbrial)Capsule,Virulent Enzyme,Adhesins,Flagella,Iron binding,protein,Virulence surface protein,Bacterial virulence factors（细菌毒力因子）,Bacterial virulence（细菌的毒力）,Virulence,（毒力）,Invasiveness,（侵袭力）,Toxin,（毒素）,Adherence&,permanent planting,（黏附与定植）,Multiplication&,diffusion,（增殖与扩散）,Anti-defense,function,of host,免疫逃逸）,Endotoxin,（内毒素）,Exotoxin,（外毒素）,Adhesion and,field planting,（黏附与定植）,Invasion,（侵入）,Multiplication and diffusion,（繁殖与扩散）,Local,diffusion（局部扩散）,Systemic diffusion（全身性扩散）,Invasiveness（侵袭力）,Definition:,Bacterial capability that can break through the physiologic barriers(skin,mucosa),settle down,multiply,and spread in the host.,Adhesive factor,s:,adhesin,and,capsule,Invasive substances,Bacterial,biofilm,1.Adhesin（粘附素）,Protiens on bacterial surface associated with adhesion.,Adhesins,bind to,adhesin receptors,on host cells.,Classification:,Pili(fimbriae)adhesin(菌毛黏附素),Non-fimbriae adhesin(非菌毛黏附素),Adhesion,Adhesin,Epithelium,Receptor,Bacterium,Capsule(荚膜)of streptococcus pneumoniae,Microcapsule,（微荚膜）,Slime layer,（黏液层）,Protect,the cell wall against attack by drugs,Inhibit ingestion and killing,by phagocytes,Play a role in the,adherence,of human tissue,Antigenicity,2.Capsule（荚膜）,3.Invasive substances（侵袭性物质）,Invasin,（侵袭素）,Encoded by invasive genes,（侵袭基因）,Mediate invading adjacent epithelial cells,Invasive enzyme,（侵袭性酶）,Some bacteria may generate invasive enzymes,which can damage body tissues and promote the invasion and diffusion of the bacteria.,4.Bacterial biofilm（细菌生物被膜）,Definition：,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.,Bacterial biofilm,Functions,Facilitates bacterial adhesion,Baffles the penetration of antibiotic and the rejection of immune system,Profits signal communication among bacteria.,Bacterial biofilm,Biofilm in the endoscope（内窥镜）,Staphylococcus epidermidis（表皮葡萄球菌）biofilm in the surface of venous,catheter（静脉导管）,Exotoxins,Endotoxins,Excreted by living cells;high concentrations 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.,Polypeptides,LPS(lipid A portion probably responsible 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.,Exotoxins,Endotoxins,Highly antigenic;stimulate formation of high-titer antitoxin(抗毒素).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(类毒素)by formalin,acid,heat,etc.Toxoids are used to immunize.,Not converted to toxoids.,Highly toxic;fatal to animals in microgram quantities or less.,Moderately toxic;fatal for animals in tens to hundreds of micrograms.,Exotoxins,Endotoxins,Usually bind to specific receptors on cells.,Specific receptors not found on cells.,Usually do not produce fever in the host.,Selective toxicity and specific clinical syndromes.,Neurotoxins(神经毒素),Cytotoxins(细胞毒素),Enterotoxins(肠毒素),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.,区别要点,外毒素,内毒素,来源,革兰阳性菌与部分革兰阴性菌,革兰阴性菌,编码基因,质粒、前噬菌体或染色体基因,染色体基因,存在部分,从活菌分泌出，少数菌崩解后释出,细胞壁组分，菌裂解后释出,化学成分,蛋白质,脂多糖,稳定性,6080，30分钟破坏,160，24小时破坏,毒性作用,强，对组织器官有选择性毒害效应，引起特殊的临床表现,较弱，各菌的毒性效应大致相同，引起发热、白细胞增多、微循环障碍、休克、DIC等,抗原性,强，刺激机体产生抗毒素；甲醛液处理脱毒形成类毒素,弱，刺激机体产生的中和抗体作用弱；甲醛液不能脱毒形成类毒素,Specific polysaccharide,LPS,Procedure,Cytotoxins（细胞毒素）,Diphtheria toxin（白喉毒素）,inhibits protein synthesis in mammalian cells and causes necrosis of cells,Diphtheria membrane on throat,Neurotoxin（神经毒素）,Tetanus toxin,（破伤风毒素）,Enterotoxin（肠毒素）,Cholera enterotoxin,Biological roles of endotoxin,Fever,（发热）,Leukopenia,and,leukocytosis,（白细胞反应）,Endotoxemia,and shock,（内毒素血症与休克）,Endotoxin,Activates,macrophages,Activates,complement,Activates,Hageman factor,IL-1,TNF,Nitric oxide,Fever and hypotension,C3a,C5a,Hypotension,Edema,Coagulation cascade,DIC,Section 4 the initiation and process of infection,Sources of infection,Pathway of bacterial entrance,Types of bacterial infection,Exogenous infection（外源性感染）,Patients,Carriers（带菌者）,Animals,Endogenous,infection（内源性感染）,Opportunistic pathogens,Sources of infection,Pathway of pathogen,entrance,Respiratory,Gastrointestinal,Genital,Skin and mucosa,Animal bites,Blood,Sexual transmission,Types of bacterial infection,Inapparent infection,（隐性感染）,Apparent infection,（显性感染）,Carrier,state,（带菌状态）Inapparent infection（隐性感染）,Subclinical infection（亚临床型感染）,An infection that has no observable symptoms.,It occurs when the host immunity is potent or the pathogenicity of the pathogen is weak.,The tip of the iceberg,Apparent infection（显性感染）,Acute infection,Chronic infection,Local infection,Generalized infection,Toxemia(,毒血症,),Endotoxemia,(,内毒素血症,),Bacteremia,(,菌血症,),Septicemia(,败血症,),Pyemia,(,脓毒血症,),Toxemia,（毒血症）,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,（内毒素血症）,Gram-negative bacteria,multiply at location or in blood stream,release a lot of amount,endotoxin,（内毒素）,released from bacterial cell rupture.,Bacteremia,（菌血症）,After entering blood,bacteria circulate but,not multiply in the blood,.,Septicemia,（败血症）,Bacteria circulate and,multiply in the blood,in which bacteria produce,toxic products,and cause high swinging type of fever and other toxic symptoms.,Pyemia,（脓毒血症）,Pyogenic,（化脓性）,bacteria produce septicemia with multiple abscess,（脓肿）,in internal organs such as spleen,liver and kidneys.,Carrier state,（带菌状态）,After inapparent infection or apparent infection,sometimes the pathogens are not eliminated in time,so the bacteria will survive and multiply in host at low speed,and bacteria spread into the environment.,Carrier（带菌者）,is important source of infection.,Hospital infection,Definition,Basic characteristics,Classification,Microbial ecological characteristics,Epidemiological characteristics,Risk factors of Nosocomial Infection,Hospital Infection（医院感染）,Nosocomial infection（医院内感染）,Hospital acquired infection（医院获得性感染）,Defintion:,Any infection,acquired while in hospital,(e.g.occurring 48 hours or more after admission and up to 48 hours after discharge).,Characteristics of nosocomial infections,Places of infection:must,in hospital,Sources of infection:,mostly endogenous,Pathogenic bacteria:,Opportunistic pathogens,Drug resistant strains,Objects of infection:,mostly patients,Mode of transmission:,intimate contact（密切接触）,Classification of nosocomial infection,Endogenous nosocomial infection,Self-infection&Normal flora,Exogenous nosocomial infection,Cross infection（交叉感染）,Enviromental infection（环境感染）,Risk factors of Nosocomial Infection,Susceptible objects:,age,and,underlying diseases,Techniques of diagnosis and therapy and invasive examinations,Important points,Definitions:,Normal flora,Opportunistic pathogen,Invasiveness,Bacterial,biofilm,Carrier state,Toxemia,Endotoxemia,Bacteremia,Septicemia,Pyemia,The differences between,exotoxin,and,endotoxin,.,