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Chapter 3 Disinfection and Sterilization 消毒与灭菌 disinfection消毒 The reduction or elimination of pathogenic microorganisms in or on materials, so they are no longer a health hazard. sterilization灭菌 The process of destroying all microbial forms. A sterile object is one free of all microbial forms, including bacterial spores. Antisepsis 防腐 Use of chemical agents on skin or other living tissue to inhibit or eliminate microbes; no sporicidal杀芽胞的 action is implied. Bacteriostasis抑菌 Asepsis 无菌 Bacteriostasis抑菌 Inhibits the growth of microorganisms. Asepsis 无菌No living microorganisms exists. Controlling Microorganisms By Physical Agents物理消毒灭菌法 High Temperature热力灭菌法 Radiation辐射杀菌法 Filtration滤过除菌法 supersonic wave超声波杀菌法 Desiccation干燥与Low Temperature低温 抑菌法 热力灭菌法 干热灭菌法— 焚烧：废弃物、尸体 灼烧：接种环、试管口 干烤：玻璃器皿 红外线：医疗器械 湿热灭菌法— 巴氏消毒法：61.0-62.8 ℃30min或71.7 ℃15-30s,主要用于牛乳消毒。 煮沸法 流动蒸汽消毒法 间歇蒸汽消毒法 高压蒸汽灭菌法 Dry heat干热：protein oxidation Hot air sterilization干烤 Incineration焚化 red heat赤热 flaming烧灼 Moist heat湿热：denature proteins and melt lipids; more effective Autoclaving: 121℃,103.4kPa, 20min cidal for both vegetative organisms and endospores Boiling water煮沸灭菌 Pasteurization巴氏消毒法: to kill particular spoilage organisms or pathogens flash method瞬间法: 71.6 °C, 15s holding method持续法: 62.9 °C, 30 min 鲜奶巴氏杀菌 63℃/30分钟 72℃/15秒 89℃/1秒 90℃/0．5秒 100℃/0．01秒 fractional sterilization间歇蒸气灭菌法 : 1) Steam heating to 100 °C for 30 min——常压/流动蒸气消毒法 Vegetative cells are destroyed but endospores survive 2) Incubate at 30°C-37°C overnight Most bacterial endospores germinate 3) Second heat treatment, 100 °C, 30 min Germinated endospores are killed. 4) Second incubation at 30°C-37 °C overnight Remaining endospores germinate 5) Third heat treatment, 100 °C, 60 min Last remaining germinated endospores are killed Radiation辐射杀菌法 Ultraviolet Radiation紫外线 波长200-300nm的紫外线具有杀菌作用。 其主要作用于DNA，使一条DNA链上相邻的两个胸腺嘧 啶共价结合 形成二聚体，导致细菌变异和死亡。 very poor penetrating power damage the eyes, cause burns, and cause mutation in cells of the skin Ionizing Radiation电离辐射 高速电子、X射线、γ射线 microwave微波 波长1mm~1m Ultraviolet Radiation microbicidal activity of ultraviolet (UV) light depends on: Mechanism: thymine-thymine dimers胸 腺嘧啶二聚体 length of exposure wavelength of UV: 260 nm - 270 nm photoreactivation光复 活作用 strong visible light Ionizing Radiation 电离辐射 X-rays and gamma rays more energy and penetrating power than UV used to sterilize pharmaceuticals and disposable medical supplies such as syringes, surgical gloves, catheters导尿管, and sutures缝合线 used to retard spoilage in seafoods, meats, poultry, and fruits 滤过除菌法 Filtration 赛氏滤器 sterilize solutions that may be damaged or denatured by high temperatures or chemical agents 玻璃滤器 薄膜滤器 超声波杀菌法 是一种机械的作用因素，每秒超过2万次 振动的声波即为超声波。常用的超声波 发生器能产生20-100千赫的声波。可使 细菌细胞壁裂解而死亡。 干燥 低温 抑菌法 干燥法Desiccation has a static effect on microorganisms by inhibiting the action of microbial enzymes 低温法Low Temperature： inhibits microbial growth by slowing down microbial metabolism低温可使细菌的新陈代谢减慢， 常用作保存细菌菌种。冷冻真空干燥法是 目前保存菌种的最好方法。 第二节 化学消毒灭菌法 消毒剂的种类：酚类、醇类、重金属盐类、氧 化剂、表面活性剂、烷化剂。 消毒剂的应用：病人排泄物与分泌物、皮肤、 粘膜、饮水、厕所、空气、手。 Antimicrobial modes of action for disinfectants and antiseptics damage the lipids and/or proteins of the semipermeable cytoplasmic membrane of microorganisms resulting in leakage of cellular materials needed to sustain life denature microbial enzymes and other proteins by disrupting the hydrogen and disulfide bonds Factors Influencing Antimicrobial Activity影响消毒灭菌效果的因素 The concentration and kind of a chemical agent used;消 毒剂的性质、浓度 The intensity and nature of a physical agent used; The length of exposure to the agent;作用时间 The temperature at which the agent is used;温度 The number of microorganisms present;数量 The species or strain of microorganism;微生物的种类 常用的化学消毒剂 类别 酚类 作用机制 常用种类 蛋白变性，细胞膜损伤 洗必泰 醇类 卤素 重金属盐 醛类 表面活性剂 去除脂类，蛋白变性 乙醇 氯气、碘酊 、碘伏 蛋白变性 红汞、硫柳汞、硝酸银 蛋白变性 福尔马林、戊二醛 蛋白变性 蛋白变性，细胞膜损伤 新洁而灭 酸碱类 破坏细胞膜、细胞壁， 十一烯酸 蛋白变性 干扰氧化、抑制繁殖 龙胆紫 染料 Different categories of such chemical agents Phenol and phenol derivatives酚衍生物 chlorhexidine洗必泰 alter membrane permeability and denature proteins ineffective against endospores Alcohols denature membranes 70% solutions of ethyl or isopropyl alcohol乙醇或 异丙醇 ineffective against endospores and non-enveloped viruses Chlorine 氯 reacts with water to form hypochlorite次氯酸盐 ions, which in turn denature microbial enzymes Iodine碘 and iodophores碘伏 denatures microbial proteins effective against some endospores Heavy metals 重金属盐 denature proteins Mercury compounds (mercurochrome红汞, merthiolate硫柳汞) : bacteriostatic, ineffective against endospores Silver nitrate 硝酸银(1%) : put in the eyes of newborns to prevent gonococcal ophthalmia淋菌 性眼炎 Aldehydes醛 denature microbial proteins Formalin 福尔马林(37% aqueous solution of formaldehyde gas) glutaraldehyde戊二醛: kill vegetative bacteria in 10-30 minutes and endospores in about 4 hours Soaps and detergents Anionic (negatively charged) detergents: mechanically remove microorganisms and other materials but are not very microbicidal. Cationic (positively charged) detergents: alter membrane permeability and denature proteins; ineffective against endospores, M. tuberculosis结 核分枝杆菌, and P. species假单胞菌. Acids and alkalies alter membrane permeability and denature proteins and other molecules Salts of organic acids: food preservatives Undecylenic acid十一烯酸: dermatophyte皮肤真 菌 infections Definitions: Sterilization – the process of destroying all forms of microbial life on an object or in a material. Disinfection – the process of destroying vegetative pathogens but not necessary endospores. Antisepsis – chemical disinfection of skin, mucous membranes or other living tissues Method for killing all microbes is called ____________。 a.disinfection b.sterilization c.antisepsis d.asepsis e.inhibiting the growth of bacteria Each of the following statements concerning the killing of bacteria is correct EXCEPT: ____________。 a.A 70% solution of ethanol kills more effectively than absolute (100%) ethanol b.An autoclave uses steam under pressure to reach the killing temperature of 121℃ c.The pasteurization of milk kills pathogens but allows many organisms and spores to survive d.Iodine kills by causing the formation of thymine dimers in bacterial DNA Which one of the following methods is most effective for killing bacterial spore____________。 a.boiling b.free flowing steam c.fractional sterilization d.autoclaving e.ultraviolet light