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STERILIZATION AND DISINFECTION Mrs.RASHMI.S. INTRODUCTION Microorganisms are the agents of contamination, infection, and decay. Microorganisms are the.

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Presentation on theme: "STERILIZATION AND DISINFECTION Mrs.RASHMI.S. INTRODUCTION Microorganisms are the agents of contamination, infection, and decay. Microorganisms are the."— Presentation transcript:

1 STERILIZATION AND DISINFECTION Mrs.RASHMI.S

2 INTRODUCTION Microorganisms are the agents of contamination, infection, and decay. Microorganisms are the agents of contamination, infection, and decay. Hence it becomes necessary to remove them from materials and areas. Hence it becomes necessary to remove them from materials and areas. Early civilization practiced salting, smoking, pickling and exposure to sunlight. Early civilization practiced salting, smoking, pickling and exposure to sunlight.

3 In mid 1800s Lister developed Aseptic techniques to prevent contamination of surgical wounds. Prior to this development: Nosocomial infections caused death in 10% of surgeries. Nosocomial infections caused death in 10% of surgeries. Up to 25% mothers delivering in hospitals died due to infection. Up to 25% mothers delivering in hospitals died due to infection.

4 DEFINITIONSTERILIZATION The process of freeing an article from microorganisms including their spores.

5 DISINFECTION: Reducing the number of pathogenic microorganismsto the point where they no longer cause diseases.

6 Sepsis: Comes from Greek for decay or putrid. Indicates bacterial contamination. Asepsis: Absence of significant contamination. Aseptic techniques are used to prevent contamination of surgical instruments, medical personnel, and the patient during surgery. Aseptic techniques are used to prevent contamination of surgical instruments, medical personnel, and the patient during surgery. Aseptic techniques are also used to prevent bacterial contamination in food industry. Aseptic techniques are also used to prevent bacterial contamination in food industry.

7 Bacteriostatic Agent: An agent that inhibits the growth of bacteria, but does not necessarily kill them.

8 u Bactericide: An agent that kills bacteria. Most do not kill Endospores. An agent that kills bacteria. Most do not kill Endospores. u Sporicide: An agent that kills spores. An agent that kills spores.

9 Methods of Sterilisation Microbial Control Methods Methods Physical Agents Physical Agents Chemical Agents Chemical Agents Mechanical Removal Mechanical Removal Methods Methods

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11 Chemical Agent Gas SterilizationDisinfection Liquids Animate ChemotherapyAntiseptics Inanimate SterilizationDisinfection

12 Mechanical Removal Methods Filtration Air Disinfection Liquids Sterilization

13 Physical Methods of Sterilisation Sterilisation By Dry Heat: Hot Air Oven Kills by oxidation effects The oven utilizes dry heat to sterilize articlesdry heat Operated between 50 o C to 250/300 o C. A holding period of 160 o C for 1 hr is desirable. There is a thermostat controlling the temperature.thermostat Double walled insulation keeps the heat in and conserves energy,energy

14 Uses: To sterilise Forceps, Scissors, Scalpels, Swabs. To sterilise Forceps, Scissors, Scalpels, Swabs. Pharmaceuticals products like Liquid paraffin, dusting powder, fats and grease. Pharmaceuticals products like Liquid paraffin, dusting powder, fats and grease.

15 FLAMING Inoculation loop or Wire, the tip of Forceps and spatulas are held in a bunsen flame till they are red hot. Inoculation loop or Wire, the tip of Forceps and spatulas are held in a bunsen flame till they are red hot.

16 INCINERATION This is an excellent method of destroying materials such as contaminated cloth, animal carcasses and pathological materials.

17 MOIST HEAT STERILIZATION Kills microorganisms by coagulating their proteins.

18 MOIST HEAT STERILISATION IS CARRIED OUT WITH FOLLOWING METHODS Temp below 100 o C: “Pasteurisation”, Inspissator. Temp below 100 o C: “Pasteurisation”, Inspissator. Temperature at 100 o C: Boiling. Temperature at 100 o C: Boiling. Steam at atmospheric pressure: Koch/Arnold’s steamer. Steam at atmospheric pressure: Koch/Arnold’s steamer. Steam under pressure: Autoclave. Steam under pressure: Autoclave.

19 Pasteurisation Process of killing of pathogens in the milk but does not sterilize it. Process of killing of pathogens in the milk but does not sterilize it. Milk is heated at 63 o C for 30 mins. Milk is heated at 63 o C for 30 mins. (HOLDER METHOD) (HOLDER METHOD) At 72 o C for Sec. Rapid cooling to 13 o C At 72 o C for Sec. Rapid cooling to 13 o C (FLASH PROCESS)

20 Water Bath

21 HOT WATER BATH To inactivate non sporing bacteria for the preparation of vaccines - Special vaccine bath at 60 o C for one hour is used To inactivate non sporing bacteria for the preparation of vaccines - Special vaccine bath at 60 o C for one hour is used Serum or body fluids containing coagulable proteins can be sterilized by heating for 1 hr at 56 o C in a water bath for several successive days. Serum or body fluids containing coagulable proteins can be sterilized by heating for 1 hr at 56 o C in a water bath for several successive days.

22 Inspissator

23 INSPISSATOR Sterilizes by heating at o C for half an hour for 3 successive days Sterilizes by heating at o C for half an hour for 3 successive days Used to sterilize media such as Lowenstein-Jensen & Loefller’s serum Used to sterilize media such as Lowenstein-Jensen & Loefller’s serum

24 TEMPERATURE AT 100 O C Boiling: Kills vegetative forms of bacterial pathogens. Kills vegetative forms of bacterial pathogens. Hepatitis virus: Can survive up to 30 minutes of boiling. Hepatitis virus: Can survive up to 30 minutes of boiling. u Endospores: Can survive up to 20 hours or more of boiling

25 Steam Sterilizer

26 STEAM AT ATMOSPHERIC PRESSURE Steam is generated using a steamer (Koch/ Arnold) Steam is generated using a steamer (Koch/ Arnold) Consists of a Tin cabinet Consists of a Tin cabinet Has a conical lid to enable the drainage of condensed steam Has a conical lid to enable the drainage of condensed steam Perforated tray above ensures materials are surrounded by steam. Perforated tray above ensures materials are surrounded by steam. For routine sterilization exposure of 90 mins is used For routine sterilization exposure of 90 mins is used

27 For media containing sugar and gelatin exposure of 100 o C for 20 min for 3 successive days is used For media containing sugar and gelatin exposure of 100 o C for 20 min for 3 successive days is used The process is termed as The process is termed as Tyndallisation /Intermittent Sterilization

28 STEAM UNDER PRESSURE - AUTOCLAVE Works on the principle of Steam under pressure Works on the principle of Steam under pressure Invented by Charles Chamberland in Invented by Charles Chamberland in 1879.Charles Chamberland1879Charles Chamberland1879

29 AUTOCLAVE

30 Autoclave consists of a vertical or a horizontal cylinder. Autoclave consists of a vertical or a horizontal cylinder. One end has an opening which is meant for keeping materials to be sterilised. One end has an opening which is meant for keeping materials to be sterilised. The lid is provided with a Pressure gauge, to measure the pressure The lid is provided with a Pressure gauge, to measure the pressure A safety valve is present to permit the escape of steam from the chamber A safety valve is present to permit the escape of steam from the chamber

31 Articles to be sterilised are placed in the basket provided Articles to be sterilised are placed in the basket provided Sterilisation is carried out under pressure at 121º for 15 mnts. Sterilisation is carried out under pressure at 121º for 15 mnts.

32 CHEMICAL AGENTS Chemical agents act by Protein coagulation Protein coagulation Disruption of the cell membrane Disruption of the cell membrane Removal of Sulphydryl groups Removal of Sulphydryl groups Substrate competition Substrate competition

33 ALCOHOLS Ethanol /Isopropyl alcohol are frequently used Ethanol /Isopropyl alcohol are frequently used No action on spores No action on spores Concentration recommended 60-90% in water Concentration recommended 60-90% in waterUses Disinfection of clinical thermometer. Disinfection of clinical thermometer. Disinfection of the skin – Venupuncture Disinfection of the skin – Venupuncture

34 ALDEHYDES Formaldehyde & Glutaraldehyde are frequently used Formaldehyde & Glutaraldehyde are frequently used Formaldehyde is bactericidal, sporicidal & has a lethal effect on viruses. Formaldehyde is bactericidal, sporicidal & has a lethal effect on viruses. Glutaraldehyde is effective against Tubercle bacilli, fungi and viruses Glutaraldehyde is effective against Tubercle bacilli, fungi and viruses

35 USES FORMALDEHYDE To preserve anatomical specimens To preserve anatomical specimens Destroying Anthrax spores in hair and wool Destroying Anthrax spores in hair and wool 10% Formalin+0.5% Sodium tetra borate is used to sterilise metal instruments 10% Formalin+0.5% Sodium tetra borate is used to sterilise metal instruments

36 USES GLUTARALDEHYDE Used to treat corrugated rubber anesthetic tubes, Face masks, Plastic endotracheal tubes, Metal instruments and polythene tubing Used to treat corrugated rubber anesthetic tubes, Face masks, Plastic endotracheal tubes, Metal instruments and polythene tubing

37 DYES Two groups of dyes are used Aniline dyes Acridine dyes

38 ANILINE DYES Are Brilliant green, Malachite green & Crystal violet Are Brilliant green, Malachite green & Crystal violet Active against Gram positive bacteria Active against Gram positive bacteria No activity against tubercle bacilli No activity against tubercle bacilli

39 ACRIDINE DYES Acridine dyes in use are orange in colour Acridine dyes in use are orange in colour Effective against Gram positive than Gram negative Effective against Gram positive than Gram negative Important dyes are Proflavine, Acriflavine,Euflavine Important dyes are Proflavine, Acriflavine,Euflavine

40 HALOGENS Iodine in aqueous and alcoholic solution has been used widely as a skin disinfectant Iodine in aqueous and alcoholic solution has been used widely as a skin disinfectant Actively bactericidal with moderate against spores Actively bactericidal with moderate against spores Chlorine and its compounds have been used as disinfectants in water supplies & swimming pools Chlorine and its compounds have been used as disinfectants in water supplies & swimming pools

41 PHENOLS Obtained by distillation of coal tar Obtained by distillation of coal tar Phenols are powerful microbicidal substances Phenols are powerful microbicidal substances Phenolic derivatives have been widely used as disinfectants for various purposes in hospitals Phenolic derivatives have been widely used as disinfectants for various purposes in hospitals Eg: Lysol, cresol Eg: Lysol, cresol

42 USES Various combinations are used in the control of pyogenic cocci in surgical & neonatal units in hospitals. Various combinations are used in the control of pyogenic cocci in surgical & neonatal units in hospitals. Aqueous solutions are used in treatment of wounds Aqueous solutions are used in treatment of wounds

43 GASES Ethylene Oxide Colourless,Highly penetrating gas with a sweet ethereal smell. Colourless,Highly penetrating gas with a sweet ethereal smell. Effective against all types of microorganisms including viruses and spores Effective against all types of microorganisms including viruses and spores

44 USES Specially used for sterilising heart-lung machines,respirators,sutures,dental equipments, books and clothing. Specially used for sterilising heart-lung machines,respirators,sutures,dental equipments, books and clothing. Also used to sterilise Glass, metal and paper surfaces,plastics, oil,some foods and tobacco. Also used to sterilise Glass, metal and paper surfaces,plastics, oil,some foods and tobacco.

45 FORMALDEHYDE GAS Widely employed for fumigation of operation theatres and other rooms Widely employed for fumigation of operation theatres and other rooms

46 BETA PROPIOLACTONE Used in fumigation Used in fumigation For sterilisation 0.2% BPL is used For sterilisation 0.2% BPL is used Has a rapid biocidal activity Has a rapid biocidal activity Very effective against viruses Very effective against viruses

47 SURFACE ACTIVE AGENTS AND METALLIC SALTS Substances which reduce the surface tension – Surface active agents

48 Cations are widely used in the form of quaternary ammonium compounds. Cations are widely used in the form of quaternary ammonium compounds. Markedly bactericidal, active against Gram positive organisms. Markedly bactericidal, active against Gram positive organisms. No action on spores, tubercle bacilli, viruses No action on spores, tubercle bacilli, viruses

49 METALLIC SALTS The salts of silver, copper and mercury are used as disinfectants. The salts of silver, copper and mercury are used as disinfectants. Act by coagulating proteins Act by coagulating proteins Marked bacteriostatic, weak bactericidal and limited fungicidal activity Marked bacteriostatic, weak bactericidal and limited fungicidal activity

50 TESTING OF DISINFECTANATS Rideal Walker test Rideal Walker test Chick Martin Test Chick Martin Test

51 Sterilisation by filtration Filtration helps to remove bacteria from heat labile liquids such as sera and solutions of sugar, Antibiotics. Filtration helps to remove bacteria from heat labile liquids such as sera and solutions of sugar, Antibiotics. The following filters are used Candle filters Asbestos filters Sintered glass filter Membrane filters

52 CANDLE FILTER

53 CANDLE FILTERS Widely used for purification of water Widely used for purification of water Two types (a) Unglazed ceramic filter – Chamberland filter (b) Diatomaceous earth filters – Berkefeld filter

54 SEITZ FILTER ASBESTOS DISCS

55 ASBESTOS FILTER Disposable single use discs Disposable single use discs High adsorbing tendency High adsorbing tendency Carcinogenic Carcinogenic Eg: Seitz filter

56 SINTERED GLASS FILTER

57 Prepared by heat fusing powdered glass particles of graded size Prepared by heat fusing powdered glass particles of graded size Cleaned easily, brittle, expensive. Cleaned easily, brittle, expensive.

58 MEMBRANE FILTER

59 MEMBRANE FILTERS Made of cellulose esters or other polymers Made of cellulose esters or other polymersUses Water purification & analysis Water purification & analysis Sterilization & sterility testing Sterilization & sterility testing Preparation of solutions for parenteral use Preparation of solutions for parenteral use

60 RADIATION Two types of radiations are used NON –IONISING IONISING

61 Non- Ionising radiation : Electromagnetic rays with longer wavelength Electromagnetic rays with longer wavelength Absorbed as heat Absorbed as heat Can be considered as hot air sterilisation Can be considered as hot air sterilisation Used in rapid mass sterilisation of prepacked Syringes and catheters Used in rapid mass sterilisation of prepacked Syringes and catheters Eg: UV rays

62 IONISING RADIATIONS X- rays, gamma rays & cosmic rays. X- rays, gamma rays & cosmic rays. High penetrative power High penetrative power No appreciable increase in the temperature – COLD STERILISATION No appreciable increase in the temperature – COLD STERILISATION Sterilise plastics Syringes, catheters, grease fabrics metal foils Sterilise plastics Syringes, catheters, grease fabrics metal foils

63 ULTRASONIC AND SONIC VIBRATION Bactericidal Bactericidal Microorganisms vary in their sensitivity, hence no practical value in sterilisation and disinfection Microorganisms vary in their sensitivity, hence no practical value in sterilisation and disinfection

64 THANK YOU


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