R.a sterilization & disinfection
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R.a sterilization & disinfection Presentation Transcript

  • 1. STERILIZATION & DISINFECTION By Dr. Riaz Ahmed
  • 2. Objectives of sterilization & Disinfection• TO BREAK THE CHAIN OF TRANSMISSION OF DISEASE SPREAD• TO DECREASE MORBIDITY & MORTALITY OF DISEASE SPREAD• TO PROLONG LIFE• TO PROMOTE HEALTH• TO PREVENT DISEASE
  • 3. Definitions •Sterilization: It is a process whereby all living organisms (both pathogenic & non-pathogenic) including their spores are either killed or removed.•Dis-infection: A process, which destroys only vegetative form of pathogenic organisms, while leaving the spores intact if any. •Infection: The entry & development OR mutliplication of inf. Agent in the body of man or animal is called infection.•Infestation: It is a state of having a parasite in OR on the body, which includes arthropods e.g., In- hook worm infestation On- scabies / louse infestation
  • 4. • DIS-INFESTATION: -• Removal OR destruction of these parasites is called Disinfestations / PARASITOSIS.• TWO IMPORTANT METHODS: -• PHYSICAL: -• CHEMICAL: -• a) PHYSICAL: -• HEAT: -• It is certain, rapid and controllable. It has one advantage over all chemical methods that when sterilization in complete, No harmful bacteria remain• TYPES: -• DRY HEAT• WET HEAT / MOIST HEAT (▲)• 1- DRY HEAT:• INCINERATION / HEATING OVER FLAME:• It is the SUREST method of heat sterilization, which is most often used by the bacteriologists when flaming a wire loop.
  • 5. • → Certain- metals, Contaminated dressings, used swabs, disposable-plastics and culture- plates are BURNT in this way.• This is in short the cheapest and safest arrangement.• HOT AIR OVEN:• HOT AIR OVEN IS NOT ONLY A POOR CONDUCTOR OF HEAT BUT ALSO HAS A POOR PENETRATION.• THEREFORE FANS ARE USED TO CIRCULATE THE AIR IN THE OVEN.• A TEMP. OF 16OO C FOR ONE HOUR IS SUFFICIENT TO STERILIZE THE INSTRUMENTS.• AT THIS HIGH TEMP; AS FABRICS WILL BE DESTROYED & RUBBER WILL MELT, SO THESE ARTICLES ARE NOT USED IN HOT AIR OVEN.
  • 6. • ARTICLES STERILIZED IN H.A.O:• 1) GLASS-SYRINGES: WHERE MOISTURE IS A PROBLEM & IT ALSO CREATS NUIASANCE.• 2) OILY LIQUIDS: THESE BECOME SOLIDIFIED IN THE PRESENCE OF MOISTURE.3) POWDERS: THESE BECOME SOLIDIFIED IN THE PRESENCE OF MOISTURE IN HOT AIR OVEN.4) VERY FINE SHARPE INSTRUMENTS: SUCH AS THOSE USED IN EYE SURGERY. THEY EITHER MAY BE DEMAGED OR GET BLUNTED BY MOIST ▲ & SO ARE PREFERABLY STERILIZED IN H.A.OVEN.
  • 7. • MOIST-HEAT / WET ▲ ONE OF THE GREAT ADVANTAGES OF MOIST HEAT OVER DRY HEAT IS THAT IT STERILIZES AT LOW TEMP & IN A SHORTER PERIOD OF TIME.• TYPES: PASTEURIZATION BOILING TYNDALLIZATION AUTOCLAVING• 1. PASTEURIZATION: - – IN THIS PROCESS MILK IS HEATED TO A CERTAIN TEMP. BELOW ITS BOILING POINT. – BY MAINTAINING AT THIS TEMP.FOR A CERTAIN PERIOD, IT IS SUFFICIENT TO KILL ALL THE PATHOGENIC & HARMFUL BACTERIA WITHOUT DESTROYING THE NUTRITIVE PROPERTIES OF MILK & THEN CHILLING IT RAPIDLY. THIS METHOD Kills 99 % OF BACTERIA: – IT IS WELL KNOWN THAT HEATING MILK AT 140O F (60OC) FOR 30 MINUTES IS SUFFICIENT TO KILL THE BACTERIA OF – TUBERCULOSIS – TYPHOID – DYSENTRY – CHOLERA & OTHER NON-SPORE BEARING
  • 8. • MILK BORNE INFECTIONS: WHICH AFFECT MAN e.g. – BRUCELLOSIS – SEPTIC SORE THROAT & INFANTILE PARALYSIS• AFTER PASTEURIZATION, THE MILK IS IMMEDIATELY COOLED DOWN TO DISCOURAGE BACTERIAL GROWTH.• THE ADVANTAGE OF PASTUERIZATION OVER BOILING IS THAT THE NUTRITIVE VALUE OF MILK IS PRESERVED.• METHODS OF PASTEURIZATION:THERE ARE TWO METHODS OF PASTEURIZATION.1.CONTINUOUS FLOW FLASH PASTEURIZATION2.THE RETAINER PASTEURIZATION• 1.CONTINUOUS FLOW FLASH PASTEURIZATION (C.F.F.P):IN THIS PROCESS MILK IS MADE TO PASS OVER A METALCOIL & A TEMP.OF 70-80O C IS MAINTAINED FOR ONEMINUTE, & THEN THE MILK IS RAPIDLY COOLED DOWN BYPASSING IT OVER COLD METAL
  • 9. 2.RETAINER PASTEURIZATION: IN THIS METHOD MILK IS HEATED AT 60-65O C AND HELD AT THAT TEMP IN A SUITABLE TANK FOR 30 MINUTES THEN IS COOLED DOWN. THIS METHOD IS MOST SATISFACTORY AS THE PATHOGENIC BACTERIA ARE KILLED WITH CERTAINITY BUT IS EXPENSIVE. 2.BOILING: IT IS EFFECTIVE METHOD OF DISINFECTION. IT PROVIDES AN ATMOSPHERE OF BOILING AND STEAM.
  • 10. • AN ADVANTAGE OF BOILING OVER PASTEURIZATION IS THAT IT IS EFFICACIOUS IN DESTROYING THE VIRUS OF HEPATIS.• THESE ARE VERY RESISTANT TO ▲ BUT ARE SAID TO BE KILLED AFTER 3 MIN. BOILING AT 100O C WHILE BOILING WILL NOT KILL SPORES.3.TYNDALLIZATION / INT.STEAMING:• THIS IS INT.STEAMING OF A SOLN AT 100O C FOR 30 MINUTES FOR THREE SUCCESSIVE DAYS.• AFTER THE FIRST STEAMING ONLY SPORES ARE LEFT BEHIND. THEY GERMINATE IN THE MEDIUM & ARE DESTROYED IN THE NEXT STEAMING.• ANY THAT SURVIVE, SHOULD BE KILLED AFTER THE THIRD STEAMING.• IT IS TRUE STERILING PROCESS BUT IS APPLICABLE ONLY TO MEDIA IN WHICH THE SPORES CAN GERMINATE & GROW AS VEGETATIVE ORGANISMS. IT FAILS WHEN APPLIED TO DRUGS, SUTURE MATERIAL & INSTRUMENTS.
  • 11. 4. AUTOCLAVING (STEAMING UNDER PRESSURE) THIS IS MOST COMMONLY USED METHOD OF STERILIZATION USED IN HOSPITAL, SO IT IS NECESSARY TO UNDER-STAND THE PRINCIPLE INVOLVED.• PRINCIPAL: BECAUSE WATER BOILS WHEN ITS V.PRESSURE BECOMES EQUAL TO THAT OF SURROUNDING AT PRESS, SO B.P OF WATER CAN BE RAISED BY INCREASING AT PRESSURE. AT NORMAL (SEA-LEVEL); AT PRESS (760mm of Hg) OR 14.7LB/sq // WATER BOILS AT 100O C, & THIS PRESSURE IS REFERED ZERO AT PRESSURE-GUAGE. IF THE PRESSURE IS INCREASED BY 10 lb / sq // , THE WATER BOILS AT 115OC & IF THE ‘ P ’ IS 15 lb/sq // , THE B.P RISES TO 121O C.• IF MATERIAL IS HELD UNDER PURE STEAM AT A TEMP. OF 121OC, FOR 15 MIN STERILIZATION CAN BE GUARANTED• AT 126O C – 10 MIN ARE SUFFICIENT• AT 134O C STERILIZATION IS COMPLETED• WITH IN 3 MINUTES
  • 12. • ADVANTAGES OF MOIST HEAT OVER DRY HEAT1) MOIST HEAT KILLS BY CO-AGULATING AND DENATURING THE PROTEINS & ENZYMES WHILE DRY ▲ ACTS BY VITUE OF• DESTRUCTIVE-OXIDATION OF CELL CONSTITUENTS.2) MOIST ▲ KILLS AT LOWER TEMP.IN A SHOTER PERIOD OF TIME.3) IT PRODUCESS NEGATIVE(-VE) PRESS. BY CONTRACTING IN ITS VOLUME WHEN IT CONDENCES BY COMING.IN CONTACT WITH COOLER SURFACE OR CABINET AND THE –VE PRESSURE BRINGS MORE STEAM
  • 13. • TO THE SAME SITE• VERY SOON THE TEMP OF SURFACE IS RAISED TO THAT OF SURROUNDING STEAM.• THEREFORE STEAM ACTS MUCH MORE QUICKLY IN HEATING EXPOSED ARTICLES.• 4) STEAM PENETRATES MUCH BETTER THAN DOES HOT AIR.• THIS IS PARTIALLY DUE TO ITS DENSITY ONLY HALF THAT OF AIR AND PARTIALLY DUE TO NEGATIVE-PRESSURE PRODUCED BY ITS CONTRACTION IN VOLUME.
  • 14. FACTORS RESPONSIBLE FOR FAILURE IN STERILIZATION• IMPROPER PACKING OF LOAD IF DRESSINGS OF THEATRE GARMENTS ARE TO BE AUTO-CLAVED, THEY MUST BE ARRANGED SO LOSSLY THAT STEAM CAN CIRCULATE INTERNALLY AROUND THEM.• DEFECTS IN AUTOCLAVE AIR SHOULD NOT ENTER THROUGH DOORS OR THROUGH CENTRAL SUPPLY.THERE SHOULD BE NO LEAKAGE.• DEFECTS IN STEAM STEAM SHOULD NOT BE EITHER SUPER-HEATED OR OVER-SATURATED AS IT WILL NOT CONDENSE-EASILY. IF THE JACKET IS TOO WORMED, THE STEAM INSIDE CABINET WILL BECOME SUPER-HEATED.
  • 15. • FAULTY OPERATION OF AUTOCLAVE• FULLY TRAINED STAFF SHOULD BE APPLIED.• TEST OF EFFICIENCY FOR HEAT STERILIZATION / AUTOCLAVE-TAPE:• THIS IS A TAPE PRINTED WITH A SENSTIVE INK WHICH UNDERGOES A COLOR CHANGE AT A SPECIFIC TEMP. IT FORMS THE BASIS OF BOWIE- DICK TEST FOR HIGH VACUUM AUTO CLAVES.• IN THE MIDDLE OF TEST PACK OF TOWELS THERE IS PLACED A SQUARE SHAPED PAPER ON TO WHICH HAS BEEN STUCK TWO STRIPS OF SPECIFIED AUTO CLAVE TAPE (3M BRAND NO.1222) IN THE SHAPE OF DIAGONALLY.
  • 16. • A TEMP OF 134O C IS APPLIED FOR 3 MINUTES.• THERE SHOULD BE UNIFORM- DEVELOPMENT OF BARS THROUGH OUT THE LENGTH OF STRIPS.• THIS INDICATES THAT STEAM HAS PASSED FREELY AND RAPIDLY TO THE CENTRE OF THE LOAD.
  • 17. OTHER PHYSICAL METHODS• FILTERATION: IT IS ALSO A VERY EFFECTIVE METHOD OF DIS-INFECTION.• THIS METHOD CAN BE USED FOR PURIFYING WATER AND AIR.• THE MATERIAL USED IN FILTER MAY BE PORCELAIN, SINTERED-GLASS, ASBESTOS, CELLULOSE ESTERS & OTHER INERT POLYMERS.• MECHANISM IS MAINLY MECHANICAL BY STOPPING THE PASSING OF SUSPENDED MICROORGANISMS WHILE THEIR PASSAGE THROUGH THE PORES IN THE FILTERED MATERIAL.
  • 18. • LIGHT:• DIRECT SUNSHINE KILLS VEGETATIVE ORGANISM• FAIRLY RAPIDLY BUT SPORES ARE MUCH MORE RESISTANT.• THE DIS-INFECTING PROPERTIES RESIDE MAINLY IN THE ULTRA-VIOLET RANGE.• U.V. LIGHT PRODUCED ARTIFICIALLY HAS POWERFUL GERMICIDAL- PROPERTIES & IS USED FOR DIS- INFECTING THE SURFACES AS WELL AS INSIDE OF THE INOCULATION CABINETS.
  • 19. • 3) IONIZING-RADIATIONS:• TWO TYPES OF IONIZING RADIATIONS ARE IN DAILY USE IN SPECIAL CENTRES.• 1.GAMMA-RADIATIONS• 2.HIGH ENERGY ELECTRONS• 1.GAMMA-RADIATIONS:• THESE ARE DERIVED FROM RADIO ACTIVE ISOTOPES SUCH AS COBALT 60 AND CAESIUM- 137.THEY POSESS GREATER PENETRATING POWER AND HENCE ARTICALS UPTO 0.5mm IN THICKNESS CAN BE STERILIZED.• 2.HIGH ENERGY ELECTRONS• THE PENETRATING POWER OF ELECTRONS DEPENDS UPON THE ENERGY BY WHICH THEY ARE ACCELERATED.
  • 20. • USES OF IONIZING RADIATION: THEY CAN BE USED TO STERILIZE A WIDE RANGE OF PRE-PACKED HEAT- SENSITIVE ARTICLES INCLUDING• BONE-GRAFTS• SURGICAL-SUTURES• SYRINGES• CATHETERS• PETRI-DISHES• RUBBER GLOVES
  • 21. • CHEMICAL METHODS• A GOOD CHEMICAL DISINFECTANT• HAS THE FOLLOWING PROPERTIES• IT SHOULD BE ACTIVE AGAINST VIDE RANGE OF ORGANISMS & SPORES.• IT SHOULD HAVE A RAPID ACTION.• ITS ACTION SHOULD HAVE NOT DECREASED BY THE PRESENCE OF ORGANIC MATTER e.g. BLOOD, PUS OR FAECAL-MATTER.• IT SHOULD NOT BE TOXIC, IRRITANT OR INDUCE HYPERSENSITIVITY-REACTION.
  • 22. • TYPES: -• 1) IN-ORGANIC DIS-INFECTANTS: -• THE HALOGENS CHLORINE & IODINE ARE MOST OFTEN IN COMMON USE; BEING TRUE STERILIZER AS THEIR ACTION IS RAPID AGAINST BOTH VEGETATIVE ORGANISMS & SPORES.• a) IODINE: - THE BEST SKIN DIS-INFACTANT IS TINCT OF IODINE, WHICH CONTAINS.• 2.5 % IODINE• 2.5 % POTASSIUM IODIDE (KI)• 90 % ETHANOL• 5 % WATER
  • 23. • DIS-ADVANTAGE: THE DIS-ADVANTAGE IS THAT:• IT IS IRRITATING TO THE RAW AREAS & MAY INDUCE AN ALLERGIC CONTACT- DERMATITIS• OTHER COMPOUNDS ARE USED WHEN IODINE IS COMBINED WITH SURFACE- ACTIVE NON-TOXIC DETERGENT.• ONE EXAMPLE IS• POLY-VINYL-IODINE OR BETADINE• THIS IS USED TO DIS INFECT FOMITES AS WELL AS TO MOP (SWEEP) THE SURGICAL INTRUMENTS.
  • 24. • CHLORINE: IT IS A POWERFUL DISINFACTANT & IS USED FOR CHLORINATION.• HYPO-CHLORITE-SOLUTIONS ARE VERY USEFUL IN THE DIS-INFECTION OF HOSPITAL – ENVIRONMENT & THE FOMITES.• THEY ARE ACTIVE PARTICULARLY AGAINST VIRUSES INCLUDING THOSE OF HEPATITIS.• AMONG HYPOCHLORITE SOLNS.ONE IS CHLORUS THAT IS TOO TOXIC TOO CORROSIVE & ALSO STRONGER FOR GENERAL USE.• MUCH WEAKER COMPOUNDS KNOWN AS MILTON (SOD-HYPOCHLORITE) MAY BE USED IN THE HOMES TO DISINFECTANT FEEDING BOTTLES OTHER COMP. CONTAINING HYPOCHLORITE SOLUTION ARE ‘VIM’& ‘AJAY’ WHICH ARE USED FOR THE DISINFECTION OF BATHS & SINKS.
  • 25. • ORGANIC-DISINFECTANTS• (a) ALCOHOL: - 50—70 % ISO-PROPYLE ALCHOL IS ALTHOUGH A CHEMICAL• DIS-INFECTANT YET IT IS NOT A TRUE STERILIZING AGENT AS IT IS IN-EFFECTIVE AGAINST SPORES.• (b) ALDEHYDES: - THEY ARE TRUE STERILIZING AGENTS• 37—41 % SOLN. OF FORMAL-DEHYDE GAS IN WATER IS A COMMERICIAL FORMULA• DIS-ADVANTAGE:• ITS DIS-ADVANTAGE IS THAT IT IS IRRITATING TO THE RAW AREAS & IN 2—4 % OF POPULATION, IT MAY INDUCE HYPERSENSITIVITY-REACTION.• (c) PHENOLS (CARBOLIC-ACID) / LISTER (1827-1912)• (WOUND INFECTION)• THESE ARE ALSO DISINFECTANTS AND THEIR GREAT ADVANTAGE IS THAT THEIR ACTION IS NOT DECREASED BY THE PRESENCE OF ORGANIC MATTER i.e. BLOOD, PUS OR FAECAL MATTER.
  • 26. • PHENOL ITSELF IS TOO TOXIC & EXPENSIVE TO BE USED AS A DISINFECTANT.• THEREFORE OTHER CLOSELY RELATED SUBSTANCES CAN BE USED e.g.• (I) LYSOL: IT IS COMBINATION OF CRESOL SOLN IN EMULSION OF SOAP• (II) CRESOL: IT IS ALSO EXTERMLY USED IS HOSP. PRACTCE.• (III) SUDAL: IT IS ALSO A POWERFULPHENOLIC COMPOUND• THESE ARE RELATIVELY CHEAP, LESS POISONOUS, THAN PURE PHENOL & ALSO ACTIVE IN THE PRESENCE OF ORGANIC MATTER.• THEIR MAIN DIS-ADVANTAGE IS THEIR DISAGREEABLE DOUR OR IRRITATING EFFECT ON SKIN• ANOTHER WIDELY, USED COMPOUND IS CHLORXYLENOL OR
  • 27. • DETTOL: THIS IS MUCH LESS IRRITANT & LESS TOXIC THAN ALL THE ABOVE MENTIONED COMPOUNDS, BUT HAS A LESS POTENT ACTION AS ITS ACTION IS ALSO ↓ed BY THE PRESENCE OF ORGANIC MATTER .
  • 28. • 3) GASEOUS DISINFECTANTS:• 1) FORMAL –DEHYDE GAS: - COLD GAS HAS A POOR PENETRATION POWER AND ALSO IS ADSORBED BY FABRICS.• HOT GAS IS MUCH MORE USEFUL AS IT PENETRATES IN FABRICS EASILY.• MAIN DRAWBACK: ITS MAIN D/B IS THAT AS 3 —4 % OF POP.IS SENSITIVE TO PARAFORMAL- DEHYDE, SO IT IS NOT VERY COMMONLY USED AS COMMERCIAL PURPOSE.• (II) ETHYLENE-OXIDE: - THIS IS COLOUR LESS FLUID, WHICH BOILS AT 120O C AND POWERFUL STERILIZATION AGENT.
  • 29. • UNLIKE, FORMALIN, IT PENETRATES WELL EVEN THROUGH PLASTICS.• IT CAN BE USED AT LOW TEMPERATURE, LEAVE NO RESIDUAL MATERIAL.• IS A DEODOURISER & IS COMPARATIVELY NON- TOXIC.• IT DOES NOT INDUCE HYPERSENSITIVITY REACTION WHEN USED AT A TEMP. B/W 50— 60O C FOR 04 HOURS• MOREOVER IT EFFECTIVELY STERILIZES THE HOSPITAL INTRUMENTS e.g. ENDOSCOPES, PLASTICS, FABRICS & ELECTRICAL INSTRUMENTS.
  • 30. • METHODS OF STERILIZATION AND DISINFECTION OF VARIOUS ARTICLES• 1) BOWLS:• THESE ARE AUTOCLAVED.• 2) BED-PANS: - THESE ARE DISINFACTANT WITH HEAT / 2.5 % IN CRESOL SOLUTION.• 3) ROOMS: - FORMAL-DEHYDE GAS MAY BE USED BUT IT IS BETTER TO USE A GOOD CHEMICAL DISINFACTANT e.g.• POTASSIUM – PERMEGANATE (KMNO4) / (PINKY)• OR CHLORINATED LIME• 4) BED-SHEETS, COTTON-BLANKETS AND BED COVERS: THESE ARE ALSO BOILED IN THE LAUNDARY-PROCESSING.• 5) MATRESS & PILLOW- COVERS: - THESE SHOULD BE COVERED IN PLASTICS AND THEIR MEAR WASHING WITH SOAP IS SUFFICIENT ENOUGH.
  • 31. • DISINFECTION OF SKIN: -• TINCT. OF IODINE IS USED AS DISINFECTANT IN PRE-OPERATIVE TREATMENT OF SKIN.• A PASTE- TEST IS PERFORMED BEFORE OPERATION TO DETACT HYPER SENSITIVE PATIENT.• AN OTHER DISINFECTANT IS 0.5 % CHLORHEXIDINE IN 70 % ETHANOL, BUT POVIDONE –IODINE / BETADINE CONTAINING 1% IODINE IS BETTER.
  • 32. • AFTER ATTENDING AN INFECTANT PERSON, HANDS SHOULD BE THOROUGHLY WASHED AND THEN IMMERSED IN AN ALCOHOLIC OR HYPOCHLORITE SOLUTION
  • 33. LIST OF DISINFECTANTS• (1) IN-ORGANIC DIS-INFECTANTS • POT-PERMEGANATE (KMNO4) / (PINKI) • BLEACHING POWDER (Caocl2) • TINCT. IODINE• (2) ORGANIC DIS-INFECTANTS • DETTOL (CHLORXYLENOLE) • PHENOL (CARBOLIC ACID)