Aspetic conditions labs
- 1. Aseptic condition in laboratory Wajaht ali
- 2. Aseptic Condition in labratories • Disinfection • Sterilization • Quality assurance
- 3. Decontamination • Decontamination: Any process for removing and /or killing microorganisms. The same term is used for removing or neutralizing hazardous chemicals and radioactive materials
- 4. Terms used in dealing with decontamination • Antimicrobial: An agent that kills microorganism or suppresses their growth and multiplecation • Antiseptic: A substance that inhibits the growth and development of microorganisms without killing them. Antiseptics are usually applied on body surface • Biocide: A general term for any agent that kills unicellular and multicellular organisms. • Chemical germicide: A chemical or a mixture of chemical s used to kill microorganisms.
- 5. Contd…. • Disinfectant: A chemical or mixture of chemical used to kill microorganisms , but not necessarily their spores. Disinfectants are usually applied on inanimate surface or objects • Disinfection: A physical or chemical means of killing microorganisms, but not necessarily their spores • Microbicide: A chemical or mixture of chemicals that kills microorganisms. The term is often used in place of “Biocide”, “Germicide” or “antimircobial”
- 6. Sterilization • A process that destroys and /or removes all classes of microorganisms and their spores
- 7. Precleaning and cleaning laboratory materials • Cleaning: Removal of visible dirt and strains • Chemical germicides: Many types of chemicals used as disinfectant and antiseptics.
- 8. Name Clean- Condition Dirty-condition Available Chlorine (Aq. NaOCl) 0.1% (1g/L) 0.5% (5g/L) Sodium hypochlorite solution (5% available Cl2) 20ml/L 100ml/L Calcium hypochlorite (70% available Cl2) 1.4g/l 7.0g/L Sodium dichloroisocyanurate tablets (60 % available Cl2) 1.7g/L 8.5g/L Chloramine (25% available Cl2) 20g/L 20g/L Formaldehyde (formalin), kills microorganism &spores 5% liq disinfectant 37% containing methanol (100ml/L) as stabilizer, used for enclosed volume as BSC and rooms .
- 9. Local environmental decontamination • For furniture, and equipment • NaOCl (1g/L) , substitute is 3% hydrogen peroxide • By fumigation, all opening in rooms must be closed • Fumigation conducted at ambient temp, atleast 21 deg C and 70% humidity, 8 hours • Ammonium bicarbonate can be used to prevent premature neutralization of HCHO • HCHO: irritant gas, suspected carcinogenic, respirators necessary.
- 10. Decontamination of BSC • BSC class I,II 0.8% paraformaldehyde should be placed on an hot electric plate or hot plate • One hot plate with ammonium bicarbonate • Humidity-70% • Sealed or closed with strong duct tape • Turned on for 1 hour, or when paraformaldehyde has all vaporized, 1 hour ammonium bicarbonate • Left cabinet overnight
- 11. Hand washing/hand decontamination • Wash hands (10 sec, throughly)with any soap with sufficient water, but use of germicidal soap is recommended for high-risk situations • Paper towel, and alcohol based hand-rubs • Use suitable golves • Hand washing, before & after entering or leaving the lab
- 12. Heat disinfectant and sterilization • Heat is the most common among the physical agents used for the decontamination (hot-air oven) • Dry-heat- totally non-corrosive, used for items which can stand temp of 160 deg.C for 2-4 hours • Burning or incineration is also a from of “dry- heat” • Moist-heat- is most effective when used as autoclaving
- 13. Autoclaving • Saturated steam under pressure (autoclave) is the most effective and reliable means of sterilizing lab materials • Correctly loaded 3 min holding time at 134 deg C 10 min holding time at 126 deg C 15 min holding time at 121 deg C 25 min holding time at 115 deg C
- 14. Contd….. • Gravity displacement autoclaves: Steam enters the chamber under pressure and displaces the heavier air downwards and through the valve in the chamber drain, fitted with a HEPA filters • Pre-vacuum autoclaves: These machines allow the removal of air from the chamber before steam is admitted. The exhaust air is evacuated through a valve fitted with HEPA filter. At the end of the cycle , the steam is automatically exhausted. Operates at 134Deg C, sterilization cycle reduced to 3 min, ideal for porous loads, not for liquids (because of vacuum)
- 15. Contd… • Fuel-heated pressure cooker autoclave • Can be used if gravity displacement is not available. They are loaded from the top and heated by gas, electricity or other types of fuel. Steam is generated by heating water in the base of the vessel, and air is displaced upwards through relief vent. When all the air is removed, the valve on the relief is closed and heat is reduced. The pressure &temp rise until the safety valve operates at present level. This is start to the holding time. At end of the cycle the heat is turned off and temp is allowed to fall to 80deg C or below is open the lid.
- 16. Precautions 1. Materials should be loosely packed, steam penetration 2. Steam should be free from corrosive inhibitors, which could contaminate the items being sterilized 3. Packed in proper plastic bag or containers 4. Trained operator, Routine monitoring, biological indicators or thermocouples should be placed at the center of each load is highly desirable 5. Cleaned daily 6. Safety valve checked for any blockage.
- 17. Incineration • Useful for disposing animal carcasses as well as anatomical and other lab waste with or without prior decontamination • Incineration, especially those with single chamber are unsatisfactory and may not completely destroy the infectious materials • Ideally , temp of primary chamber should be 800 deg C, and sec. chamber 1000 deg.C • Environment friendly bags and energy efficient source should be used. • Licensed Land fill sites
- 18. Quality assurance • Accuracy • Precision Quality control Quality assurance Quality assessment 1. Internal checks 2. External Checks • Negative &positive controls • Calibration standards, temp, pipette, aids, freezer, deep freezer, weighing machine, BSC,
- 19. Chemical, Fire and electrical safety
- 20. Disinfection • A physical or chemical means of killing microorganisms, but not necessarily their spores