1. CHAPTER 9 sterilization & disinfection

2. biocide  A chemical agent that inactivates microorganisms  Usually broad-spectrum

3. bacteriostatic  A biocide is able to inhibit bacterial multiplication  Multiplication resumes upon removal of the agent

4. bactericidal  A biocide is able to kill B.  The “killed” organism can no longer reproduce, even after being removed from contact with the agent

5. Sterilization:  Completely destroys or removes all microbial life, including spores.  by physical or chemical process

6. disinfectants  Products or biocides used to kill microorganisms on inanimate objects or surfaces.

7. septic  Presence of pathogenic microbes in living tissue

8. antiseptic  A biocide or product that destroys or inhibits the growth of M. in or on living tissue

9. aseptic  Absence of pathogenic microbes

10. Disinfection killing, or removal of microorganisms that may cause disease. killing, or removal of microorganisms that may cause disease.

11. Methods for control of microorganisms Physical methods Heat Hot-air sterilizer Heat Hot-air sterilizer Autoclaving Autoclaving Radiation Radiation Filtration Filtration Ultrasound Ultrasound Dryness Dryness Low temperature Low temperature Chemical agents

12. Section 1 physical sterilization and disinfection physical sterilization and disinfection

13. Physical agents  heat  radiation  filtration ---- Remove organisms  Ultrasonic and sonic vibrations  Freezing Impart energy

14. heat denature or coagulate proteins denature or coagulate proteins damage membrane damage membrane enzymatic cleavage of DNA enzymatic cleavage of DNA moist heat sterilizes at a lower temperature moist heat sterilizes at a lower temperature than dry heat

15. Two ways 1.Dry heat 2.Moist heat

16.  Incineration  Direct flames  Hot-air sterilizer  160-170  C for 2 hours----spores  Glass petri dishes and pipettes  Infrared  microwave Dry heat

17.  For glassware and materials impervious to steam  Kill of all organisms, including the spore formers

18. Moist heat Autoclaving: pressure: 15 1b/in 2 pressure: 15 1b/in 2 temperature: 121 temperature: 121 held: 15-20 minutes held: 15-20 minutes autoclaves or pressure cookers autoclaves or pressure cookers kill both vegetative organisms and endospores kill both vegetative organisms and endospores

19. pasteurization  Two methods:  62 ℃ for 30 minutes  72 ℃ for 15 seconds  to kill particular spoilage organisms or pathogens  Primarily for milk

20. 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

21. 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 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 fractional sterilization:

22. radiation Two types of radiation ultraviolet light ultraviolet light Ionizing Radiation Ionizing Radiation

23. UV light at 250-260 nm absorbed by purine and pyrimidin bases of DNA form thymine dimers inhibit DNA replication

24.  very poor penetrating power  To sterilize the air and any exposed surfaces  damage the cornea and skin :damage the eyes, cause burns, and cause mutation in cells of the skin UV light

25. filtration  for certain solutions that may be damaged or denatured by high temperatures or chemical agents  has a pore size of 0.22 μm  physically trap particles larger than the pore size and retain smaller particles

26. Section 2 chemical sterilization and disinfection chemical sterilization and disinfection

27.  Alcohols 醇  Aldehydes 醛  Halogens 卤素  Heavy metals 重金属  Phenolics 酚  Detergents 去污剂 Chemical agents

28. 常用的化学消毒剂 类别作用机制常用种类 酚类蛋白变性，细胞膜损伤洗必泰 醇类去除脂类，蛋白变性乙醇 卤素蛋白变性 氯气、碘酊 、碘伏 重金属盐蛋白变性红汞、硫柳汞、硝酸银 醛类蛋白变性福尔马林、戊二醛 表面活性剂蛋白变性，细胞膜损伤新洁而灭 酸碱类染料 破坏细胞膜、细胞壁， 蛋白变性 干扰氧化、抑制繁殖十一烯酸龙胆紫

29.  Nature, concentration and acting time of the disinfectant  Type and amount of the microbe  Temperature  pH  Organic matter Factors affecting the results

30. Chemical agents 1.disruption of the lipid-containing cell membrane 2.modification of proteins 3.modification of DNA

31. disruption of the cell membrane Alcohols  to clean the skin  disorganizing the lipid structure in membranes membranes  denature proteins  far more effective at 70% than at 100%

32. Detergent  Surfactants  Disrupt the membrane  Widely used for skin antisepsis

33. phenols  The first disinfectant used in the operating room  Too caustic  Damage membranes and denature proteins

34. modification of proteins Chlorine to purify the water supply to purify the water supply to treat swimming pools to treat swimming pools an oxidizing agents an oxidizing agents

35. iodine the most effective skin antiseptic tincture: to prepare the skin prior to tincture: to prepare the skin prior to blood culture blood culture irritate to the skin irritate to the skin iodophors: to prepare the skin prior to iodophors: to prepare the skin prior to surgery surgery less irritating less irritating

36. Heavy metals mercury and silver: have the greatest antibacterial have the greatest antibacterialactivity bind to sulfhydryl---- block bind to sulfhydryl---- block emzymatic activity

37. Ethylene oxide for heat-sensitive materials for heat-sensitive materials alkylate both proteins and nucleic alkylate both proteins and nucleicacids