微生物的控制讲稿.ppt

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1、微生物的控制第一页，讲稿共七十页哦Workers in protective garments prepare the Hart Office Building for decontamination第二页，讲稿共七十页哦Cleaning products aisle in a store第三页，讲稿共七十页哦Contents7.1 Overview of Microbial Control7.2 Methods of Physical Control7.3 Chemical Agents in Microbial Control第四页，讲稿共七十页哦7.1 Overview of Micro

2、bial Control第五页，讲稿共七十页哦1.Categories of Microbial ControlPhysical agentsChemical agentsMechanical removal第六页，讲稿共七十页哦Microbial Control MethodsIncineration (焚烧)Sanitization (卫生处理)Disinfection(消毒)Sterilization (灭菌)Antisepsis (防腐)Degermation(除菌)第七页，讲稿共七十页哦2.Relative Resistance of Microbial FormsHighest r

3、esistance:bacterial endosporesModerate resistance:Protozoan cysts(胞、囊);some fungal sexual spores;some viruses(hepatitis B virus and the poliovirus.Naked viruses are more resistant than enveloped forms).Bacteria with more resistant vegetative cells:Mycobacterium tuberculosis(结核分枝杆菌),Staphylococcus au

4、reus(金黄色葡萄球菌),Pseudomonas(假单胞菌)第八页，讲稿共七十页哦Least resistance:Most bacterial vegetative cells;fungal spores and hyphae;enveloped viruses;yeasts;protozoan trophozoites(营养体)第九页，讲稿共七十页哦MethodSporesVegetative FormsRelative ResistanceHeat(moist)120801.5Radiation(X-ray)dosage0.4 Mrad0.1 Mrad4UV rays1.5 h10 m

5、in9Sterilizing gas(ethylene oxide)1,200 mg/L 700 mg/L1.7Sporicidal liquid(2%glutaraldehyde)3 h10 min18Relative Resistance of Bacterial Endospores and Vegetative Cells to Control Agents乙撑氧，ethyiene乙烯戊二醛第十页，讲稿共七十页哦3.Terminology第十一页，讲稿共七十页哦 SterilizationSterilization(灭菌)is a process that destroys or re

6、moves all viable microorganisms,including viruses.Sterile(无菌):Any material that has been subjected to this process is said to be sterile.This term has the strictest sense.An object cannot be slightly sterile or almost sterile-it is either sterile or not sterile.第十二页，讲稿共七十页哦Most sterilization is perf

7、ormed with a physical agent such as heat第十三页，讲稿共七十页哦 Microbicidal Agents(微生物杀菌剂)The root-cide means to killBactericide-is a chemical that destroys bacteria except for those in the endospore stageFungicide-is a chemical that can kill fungal spores,hyphae,and yeastsVirucide-is any chemical known to in

8、activate viruses,especially on living tissueSporicide-is an agent capable of destroying bacterial endospores第十四页，讲稿共七十页哦 Agents That Cause Microbistasis(微生物抑菌剂)Stasis(停滞)Microbes are temporarily prevented from multiplying but are not killed outrightBacteriostatic agents(细菌抑菌剂)prevent the growth of b

9、acteria on tissues or on objects in the environment.Fungistatic chemicals(真菌抑制剂)inhibit fungal growth第十五页，讲稿共七十页哦 Germicides,Disinfection,AntisepsisGerm:is a common term for a pathogenic microbe(致病菌)Germicide(杀菌剂，指致病菌),also called microbicide,is any chemical agent that kills pathogenic microorganism

10、sA germicide can be used on inanimate(nonliving)materials or on living tissue,but it ordinarily can not kill resistant microbial cells第十六页，讲稿共七十页哦Disinfection(消毒)refers to the use of a physical process or a chemical agent(disinfectant消毒剂)to destroy vegetative pathogens(致病菌)but not bacterial endospor

11、esDisinfectants(消毒剂)are normally used only on inanimate objects,because,in the concentrations required to be effective,they can be toxic to human and other animal tissue第十七页，讲稿共七十页哦Examples of disinfection include:applying a solution of 5%bleach(漂白粉)to an examining tableboiling food utensils used by

12、 a sick personimmersing thermometers in an iodine solution between uses对物而言第十八页，讲稿共七十页哦In modern usage,sepsis(腐烂)is defined as the growth of microorganisms in the body or the presence of microbial toxins in blood and other tissuesAntisepsis(防腐):Antiseptics(防腐剂)are applied directly to exposed body su

13、rfaces(skin and mucous membranes粘膜),wounds,and surgical incisions(切口)to destroy or inhibit vegetative pathogens第十九页，讲稿共七十页哦Examples of antisepsis(防腐)include:preparing the skin before surgical incisions with iodine compounds;swabbing an open root canal with hydrogen peroxide(H2O2);and ordinary handwa

14、shing with a germicidal soap.对人而言第二十页，讲稿共七十页哦Do not require to kill or inhibit microorganisms,but to reduce the levels of microorganisms.The levels of microorganisms is also called the microbial load.Aim:decrease greatly the possibility of infection or spoilage.Sanitization(卫生处理),Degermation(除菌)第二十一

15、页，讲稿共七十页哦Application:Restaurants,dairies,breweries,and other food industries often handle large numbers of soiled(污染的)utensils that could readily become sources of infection and spoilage.These industries must keep microbial levels to a minimum during preparation and processing.第二十二页，讲稿共七十页哦Sanitizat

16、ion(卫生处理):is any cleansing technique that mechanically removes microorganisms as well as other debris to reduce contaminations to safe level.第二十三页，讲稿共七十页哦Examples of sanitization:Cooking utensils,dishes,bottles,cans,and used clothing that have been washed and dried may not be completely free of micr

17、obes,but they are considered safe(sanitary卫生)for normal use.Air sanitization with UV lamps reduces airborne microbes in hospital rooms,clinics,and lab installations.对物而言第二十四页，讲稿共七十页哦Degermation(除菌):is to reduce the numbers of microbes on the human skinThis process usually involves scrubbing(擦洗)the s

18、kin or immersing it in chemicals,or both,mechanically removing potential pathogens on the outer layers of the skin第二十五页，讲稿共七十页哦Examples of Degermation:Surgical handscrub,the application of alcohol wipes to the skinThe cleansing of a wound with germicidal soap and waterThe concepts of degermation and

19、 antisepsis overlap对人而言第二十六页，讲稿共七十页哦4.What Is Microbial Death?第二十七页，讲稿共七十页哦 Concept of Microbial DeathMicrobiological definition of death:refers to the permanent loss of reproductive capacity,even under optimum growth conditions.第二十八页，讲稿共七十页哦 Factors That Affect Death Ratea.The process of sterilizat

20、ion第二十九页，讲稿共七十页哦b.The number of microorganism.A higher load of contaminants requires more time to destroy第三十页，讲稿共七十页哦c.The nature of the microorganisms in the population(vegetative cells,spores)第三十一页，讲稿共七十页哦d.The mode of acton of the agent.How does it kill or inhibit the microorganism?第三十二页，讲稿共七十页哦5

21、.How Antimicrobial Agents Work:Their Modes of ActionFour categories:the cell wall:penicillins the cell membrane:detergents(去污剂，surfactants表面活性剂)DNA,RNA:x-ray,g-ray,UV proteins:denaturation,alcohol 第三十三页，讲稿共七十页哦Mode of action of surfactants(表面活性剂)on the cell membrane.Surfactants inserting in the lipo

22、idal layers disrupt it and create abnormal channels that alter permeability and cause leakage both into and out of the cell.第三十四页，讲稿共七十页哦Modes of action affecting protein function第三十五页，讲稿共七十页哦7.2 Methods of Physical Control第三十六页，讲稿共七十页哦1.Heat As an Agent of Microbial ControlElevated temperature(exce

23、eding the maximum growth temperature):microbicidal(杀菌)Lower temperature(below the minimum growth temperature):microbistatic(抑菌)Moist heat:hot water,boiling water,vaporized water(steam),60-135Dry heat:hot air,flame(incineration 焚烧),electric heating coil,160-several thousand 第三十七页，讲稿共七十页哦 Mode of acti

24、on and relative effectiveness of heatMoist heat:denatures proteinsDry heat:dehydrates the cell,removing the waterComparison of their effectiveness(see table)第三十八页，讲稿共七十页哦ModeTemperatureTime to sterilizeMoist heat 121 15 min125 10 min134 3 minDry heat121 600 min140 180 min160 120 min170 60 minCompari

25、son of sterilization with moist and dry heat第三十九页，讲稿共七十页哦 Heat resistance and thermal death of spores and vegetative cells第四十页，讲稿共七十页哦OrganismTemperatureTime of Exposure to Kill SporesMoist HeatBacillus subtilis121 1 minB.stearothermophilis 121 12 minClostridium botulinum120 10 minCl.tetani105 10 mi

26、nDry HeatBacillus subtilis121 120 minB.stearothermophilis 140 5 minClostridium botulinum120 120 minCl.tetani100 60 minThermal death times of various endospores第四十一页，讲稿共七十页哦Microbial TypeTemperature()Time(Min)Non-spore-forming pathogenic bacteria5828Non-spore-forming nonpathogenic bacteria6118Vegetat

27、ive stage of spore-forming bacteria5819Fungal spores7622Yeasts5919Nonenveloped viruses5729Enveloped viruses5422Average thermal death times of vegetative stages of microorganisms第四十二页，讲稿共七十页哦 Practical concerns in the use of heat:thermal death measurementsThermal death time(TDT):the shortest length o

28、f time required to kill all test microbes at a specific temperatureThermal death point(TDP):thermal death temperature,the lowest temperature required to kill all microbes in a sample in 10 miniutes第四十三页，讲稿共七十页哦 Methods of moist heatFour ways to control microbes with moist heat:Steam under pressureNo

29、npressurized steamBoiling waterPasteurization 第四十四页，讲稿共七十页哦a.Steam under pressure高压蒸汽灭菌高压蒸汽灭菌锅杀菌斧第四十五页，讲稿共七十页哦Sterilization with steam under pressurePressureTemperature()Mpakg/cm2lb/in2 空气全排出空气排出空气不排除0.070.7010115.6105900.101.0515121.3112100NOTE:It is not the pressure by itself that is killing micro

30、bes but the increased temperature it producespound/inch2第四十六页，讲稿共七十页哦A large automatic autoclave used in sterilization by drug companies第四十七页，讲稿共七十页哦Cutaway section,showing autoclave components存水弯，汽水闸，活板门第四十八页，讲稿共七十页哦b.Nonpressurized steamIntermittent Sterilization(间歇灭菌)Some substances that cannot w

31、ithstand the high temperature of the autoclave can be subjected to intermittent sterilization 100 30-60 min,3 times,2 interval cultivations-kill spores but not break down heat sensitive substances(e.g.sera,egg,or carbohydrates)第四十九页，讲稿共七十页哦c.PasteurizationPasteurization(巴斯德消毒法)is a technique in whic

32、h heat is applied to liquids to kill potential agents of infection and spoilage,while at the same time retaining the liquids flavor and food value.Pasteurization:巴斯德所创，最初采用低于100的消毒法，目的是既杀灭致病菌和腐败菌，又保留食品的风味和价值第五十页，讲稿共七十页哦Disinfection of beverages,such as milk,fruit juice,beer,and wine adopts pasteuriz

33、ation.Temperatures adopted:65 for 30 min80 for 15 min90 for 5 min134 for 1-2 sec(ultrahigh temperature)第五十一页，讲稿共七十页哦d.Boiling Water:DisinfectionExposing materials to boiling water for 30 min will kill most non-spore-forming pathogens,including resistant species such as the tubercle bacillus(结核杆菌)and

34、 staphylococci(葡萄球菌).Boiling water is a fairly reliable way to sanitize and disinfect household materials(家用消毒法).第五十二页，讲稿共七十页哦 Dry heat:hot air and incinerationIncineration(burning焚烧)：Bunsen burner:1,870 at its hottest point,common practice in the microbiological laboratories.Furnace/incinerator:800

35、-6,500,regularly employed in hospitals and research labs for complete destruction and disposal of infectious materials such as syringes,needles,dressings,bandages,bedding,pathology(病理学)samples.第五十三页，讲稿共七十页哦Hot air(热空气)：Dry oven(烘箱):hot-air oven,sterilization with dry oven requires exposure to 160-17

36、0 for 1-2 hours.Substances appropriate for dry ovens are glassware,metallic instruments,powders,and oils that steam does not penetrate well.This method is not suitable for plastics,cottons,and paper,which may burn at high temperatures,or for solutions,which will dry out.第五十四页，讲稿共七十页哦2.The Effects of

37、 Cold and Desiccation(干燥)Note that cold merely retards(delays延迟，减缓)the activities of most microbes.Use:PreservationDesiccationLyophilization:冻干第五十五页，讲稿共七十页哦As a general rule,chilling,freezing,and desiccation should not be construed(解释,分析)as methods of disinfection or sterilization,because their anti

38、microbial effects are erratic(irregular)and uncertain,and one can not be sure that pathogens subjected to them have been killed.第五十六页，讲稿共七十页哦3.Radiation As a Microbial Control Agent第五十七页，讲稿共七十页哦Cellular effects of irradiationa.Ionizing radiation:gamma rays,X rays,high-speed electrons,cobalt 60b.Noni

39、onizing radiation:UV第五十八页，讲稿共七十页哦Formation of pyrimidine dimers by the action of ultraviolet radiation第五十九页，讲稿共七十页哦This irradiation machine uses radioactive cobalt 60 as a gamma radiation source to sterilze fruits,vegetables,meat,fish,and spices.(pallet货盘)Controversy?第六十页，讲稿共七十页哦A UV treatment syste

40、m for disinfection of wastewater第六十一页，讲稿共七十页哦4.Sound Waves in Microbial ControlSonication(超声波处理)打断核酸第六十二页，讲稿共七十页哦5.Sterilization by Filtration:Techniques for Removing Microbes第六十三页，讲稿共七十页哦Membrane filtration第六十四页，讲稿共七十页哦7.3 Chemical Agents in Microbial Control第六十五页，讲稿共七十页哦类型名称及使用浓度作用机制应用范围重金属盐类0.05%

41、-0.1%升汞与蛋白质巯基结合使其失活非金属物品，器皿2%红汞皮肤，粘膜，小伤口0.01%-0.1%硫柳汞皮肤，手术部位，生物制品防腐0.1%-0.5%CuSO4杀植病真菌与藻类0.1%-1%AgNO3沉淀蛋白质使其变性皮肤，滴新生儿眼睛(防淋病病菌感染)酚类3%-5%石炭酸蛋白质变性，损伤细胞膜地面，家具，器皿2%来苏儿(煤酚皂)皮肤醇类70%-75%乙醇蛋白质变性，损伤细胞膜，脱水，溶解类脂皮肤，器械 若干重要表面消毒剂及其应用第六十六页，讲稿共七十页哦类型名称及使用浓度作用机制应用范围酸类 5-10 ml/m3醋酸(熏蒸)破坏细胞膜和蛋白质房间消毒(防呼吸道传染)醛类 0.5%-10%甲

42、醛破坏蛋白质氢键或氨基物品消毒，接种箱、接种室熏蒸，精密仪器消毒2%戊二醛(pH8左右)气体 600 mg/L环氧乙烷有机物烷化，酶失活手术器械，皮毛，食品，药物氧化剂0.1%KMnO4氧化蛋白质的活性基团皮肤，尿道，水果，蔬菜3%H2O2污染物件的表面0.2%-0.5%过氧乙酸皮肤，塑料，玻璃，人造纤维1 mg/L臭氧O3食品若干重要表面消毒剂及其应用（续）第六十七页，讲稿共七十页哦类型名称及使用浓度作用机制应用范围卤素及化合物0.2-0.5 mg/L氯气 破坏细胞膜、酶、蛋白质饮水，游泳池水10%-20%漂白粉地面，厕所0.5%-1%漂白粉饮水，空气(喷雾)，体表0.2%-0.5%氯胺室内

43、空气(喷雾)，表面消毒4 mg/L二氯异氰尿酸钠饮水3%二氯异氰尿酸钠空气(喷雾)，排泄物，分泌物2.5%碘酒酪氨酸卤化，酶失活皮肤若干重要表面消毒剂及其应用（续）第六十八页，讲稿共七十页哦类型名称及使用浓度作用机制应用范围表面活性剂0.05%-0.1%新洁而灭蛋白质变性，破坏膜皮肤，粘膜，手术器械0.05%-0.1%杜灭芬皮肤，金属，棉织品，塑料染料2%-4%龙胆紫与蛋白质羧基结合皮肤，伤口若干重要表面消毒剂及其应用（续）第六十九页，讲稿共七十页哦 术语半致死剂量(50%lethal dose,LD50)是评定药物毒性强弱的指标之一，指在一定条件下，某化学药剂能杀死50%试验动物时的剂量。第七十页，讲稿共七十页哦