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بسم الله الرحمن الرحيم STERILIZATION. Prof. Khalifa Sifaw Ghenghesh Dept. of Medical Microbiology, Faculty of Medicine, Tripoli University Tripoli - Libya. What is Sterilization?. The removal of all forms of living material. - PowerPoint PPT Presentation
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الرحيم الرحمن الله بسم
STERILIZATION
Prof. Khalifa Sifaw GhengheshDept. of Medical Microbiology,
Faculty of Medicine, Tripoli UniversityTripoli - Libya
What is SterilizationWhat is Sterilization??
• The removal of all forms of living material.
• Important: First Objects to Be Sterilized Should Be Cleaned by Washing.
METHODS OF STERILIZATION
1. DRY HEAT– Red Heat– Hot - Air Oven: • 160o/ 60 minutes• 180o/ 20 minutes
2. MOIST HEAT:– Tyndallization: > 100oC/ 30 minutes
On 3 Consecutive Days.– The Autoclave: > Pressurized Steam.• 121oC/ 1.1 bar for 15 minutes.• 134oC/ 2.2 bar for 3 minutes.
• TESTS FOR AUTOCLAVE FUNCTION
–The Bowie-Dick Autoclave Tape Test:–Browne's Tubes:–Automatic Controls or Pen Records:–Bacteriological Tests (Spore Tests):
• 2. IRRADIATION• i. Ultra - Violet Radiation (UV):– a. Not Recommended.– b. Poor penetration in Air.– c. Suitable to Reduce Microbial Counts
in Safety Cabinets.
• ii. Gamma - Ray Radiation– Source: Cobalt 60.– a. Lethal to All Forms of Microbial
Life.– b. Used Commercially.
• 3. FILTRATION–Bacterial Stopping Filters.
• 4. GASES• i. Ethylene Oxide Gas:– a. Ventilators.– b. Toxic & Explodes When Mixed
with Air.
• ii. Formaldehyde:– a. Rooms and Lab. Cabinets.
• 5. LIQUIDES: –Disinfectants.
• i. Glutaraldehyde:– a. Sterilizing Heat Sensitive Pieces
of Equipments.
Forms of Sterilization by Heat and Principle Uses._______________________________________________________________
Type of Heat Use_______________________________________________________________
DRY:1. Red Heat. Microbiological Loops. Incineration of
UsedLab. Culture Plates.
2. Hot - Air Oven. Many Surgical & Dental Instruments but Not Fabrics or Rubber.
----------------------------------------------------------------------------------------------------------
MOIST:1. Steam at 100oC Some Bacteriological Media.On 3 Consecutive Days.
2. Pressurized Most Surgical and Dental Instruments,Steam (Autoclave). Fabrics & Dressings (If Wrapped); Most
Microbiological Media & Glassware. _______________________________________________________________
Heat Content of Water and Steam_______________________________________
Phase Temp. Heat Content (kJ/kg)
of oC Sensible Latent Total
Water Heat Heat Heat
-----------------------------------------------------------------
Liquid 100 419 0 419
Vapour 100 419 2257 2676
Vapour 121 509 2199 2708
Vapour 135 567 2160 2727
_______________________________________
• PROPERTIES OF STEAM
–i. Moisture content
–ii. Heat content
–iii. Penetration
PRESSURE STEAM STERILIZERS
1. Porous Load Sterilizers (Prevacuum type):• Removal of air and heating of the chamber.
• Sterilization of the load.
• Removal of steam and drying of the load by mechanical evacuation.
• Admission of filtered air to restoration atmospheric pressure.
2. Downward Displacement Jacketed Sterilizers:
• Gradual displacement of air by incoming steam while the chamber is heated to the selected sterilizing temp.
• Sterilization of the textile packs for 30 min/ 121oc.• Drying of the load by partial vacuum.• Restoration of the chamber to atmospheric pressure.
3. Unwrapped Instrument and Utensil
Sterilizers:• DSL autoclaves
4. Fluid Sterilizers:• e.g. water, iv solutions, etc.
• Factors influencing sterilization time for fluids:– rate of heating of the chamber:
– type of container:
–viscosity of the liquid:
–volume of the liquid:
– trapped air:
" الرحيم الرحمن الله "بسم DISINFECTION AND DISINFECTANTS
Prof. Khalifa Sifaw GhengheshDept. of Medical Microbiology,
Faculty of Medicine, Al-Fateh University
Tripoli - Libya
DisinfectionDisinfection
• The removal of most of the pathogenic microorganism, but often non-pathogenic or resistant forms of pathogens remain.
Methods of DisinfectionMethods of Disinfection
• A. Cleaning• Instruments with high risk organic
material >>
• Treat with strong disinfectant >> Cleaning >> Sterile or dispose of.
B. Disinfection by Heati. Pasteurizationii. Boiling wateriii. Flaming off alcohol
C. Physical Methods• UltrasonicsUltrasonic vibration >
Disrupte microorganismse.g. Ultrasonic scalers.
D. Chemical DisinfectantsDenaturing protein or lipidAct: Disrupting the biosynthetic pathways
I. Phenols• Clear phenolic solutions:
• Black and White Phenolic Compounds:
• Chloroxylenol: (Dettol)
• Hexachlorophane: Pre-operative scrub
II. Halogenic Compounds
• Hypochlorites: Effective > HBV
• Iodine + Alcohol
Pre-operative skin antiseptic.
• Bovidone Iodine:
an anti-plaque agent.
III. Aldehydes• Formaldehyde• Gluteraldehyde• Alcohol
-----------------------
Antiseptics• Are bacteriostatic agents that can
be used on skin and mucosal surfaces.
IV. Diguanides• Chlorhexdine
0.5% + 70% alcohol >>> Skin
disinfectant
• Chlorhexidine gluconate Treatment of oral candidosis + oral
ulceration
V. Quaternary Ammonium Compounds
• Cetrimide
VI. Organic Dyes• e.g. gentian violet
• Factors Affecting the Effectiveness of Disinfectants:
• Tests of the Proper Functioning of Liquid Disinfectants:" In-use" Tests.
Storage of Sterile Instruments• Never store instruments in liquid
disinfectants.
Waste Disposal
Special Problems• HBV, HCV and HIV (AIDS)
Sterilization and Disinfection
in Dentistry
• Sterilization >>> Autoclave.
• Dental instruments can and should be
autoclaved after each patient.
• Nozzles of air and water spray: ??