Dwd sterilization i lect.
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Nosocomial infections from lack of sterilization caused high death rates from surgeries and childbirth. The document then defines and compares various sterilization, disinfection, and aseptic techniques including their mechanisms and uses. It provides details on specific sterilization methods like autoclaving, Tyndallization and membrane filters. It also discusses non-ionizing and ionizing radiation sterilization methods and their applications.
Dwd sterilization i lect.
- 3. • Nosocomial infections caused death in 10% of surgeries. • Up to 25% mothers delivering in hospitals died due to infection.
- 5. Sterilisation : – It is a process by which an article, surface or medium is made free of all microorganisms either in vegetative or spore form. Disinfection : – Destruction of all pathogens or organisms capable of producing infections but not necessarily spores. – All organisms may not be killed but the number is reduced to a level that is no longer harmful to health.
- 6. Antiseptics : –Chemical disinfectants which can safely applied to living tissues and are used to prevent infection by inhibiting the growth of microorganisms. Asepsis : –Technique by which the occurrence of infection into an uninfected tissue is prevented.
- 11. • Sunlight
- 12. • Drying
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- 24. Pasteurization, Water Bath, Vaccine Bath, Inspissator. Boiling Koch / Arnold’s Steamer, Tyndallization Autoclave
- 31. Tyndallisation /Intermittent Sterilization / Fractional sterilization • Principle – Vegetative cells & spores are killed during the first heating & that the more resistent spores subsequently germinate & are killed during the second or the third heating.
- 32. Tyndallisation /Intermittent Sterilization / Fractional sterilization • Principle – Vegetative cells & spores are killed during the first heating & that the more resistent spores subsequently germinate & are killed during either the second or the third heating. • Useful in sterilizing heat sensitive culture media containing carbohydrates, egg or serum which are damaged by higher temperature of autoclave.
- 34. –Consists of vertical or horizontal cylinder of gunmetal or stainless steel. –Lid is fastened by screw clamps and rendered air tight by an asbestos washer. –Lid bears a discharge tap for air and steam, a pressure gauge and a safety valve.
- 36. –Temperature – 121 °C –Chamber pressure -15 lb per square inch. –Holding time – 15 minutes –Others : • 126°C for 10 minutes • 133°C for 3 minutes
- 43. DEEP FILTERS Name of Filter Made up of Examples Comments & Uses Candle filters 1.Diatomaceous earth 2.Unglazed porcelain Berkefeld filters Chamberlain filters They are available in different porosity. Mostly used for the purification of drinking water and industrial uses. Asbestos filters Asbestos (magnesium silicate) Seitz and Sterimat filters They have high adsorbing capacity and tend to alkalinize the filtered fluid. These are disposable , single use discs available in different grades. Asbestos is carcinogenic hence its use is discouraged. Sintered glass filters Fusing finely powdered glass particles They are expensive and brittle. They have low absorptive property. MEMBRANE FILTERS Cellulose esters Other polymers They are routinely used for water purification and analysis, sterilization, sterility testing and solutions of parenteral use. Wide range of average pore diameters(APD) are available but 0.2mm size is widely used.
- 45. Non – Ionizing Radiation Types Produced by Mode of action Uses Comments Low energy (Infrared and ultraviolet rays) UV lamps DNA damage Infrared rays: Sterilization of prepacked items such as syringes and catheters. Ultraviolet rays: Used for disinfecting operation theaters and laboratories. Use of UV light is limited by penetration and hazardous. Ionizing Radiation High energy ionizing type (Gamma rays and high energy electrons such as X-rays and cosmic rays) Cobalt-60 based instruments DNA damage For the sterilization of antibiotics, hormones and other pre- packed disposable items such as catheters, gloves, syringes, infusion sets, oils, animal feeds, etc. They are expensive. They are very effective due to high penetrative power.