Embed Size (px)
Citation preview
DefinitionDefinition
Sterilization: The freeing of an article from all living organisms including bacteria and their spores.
Disinfection: Removal of some types of pathogenic organisms usually not including spores.
Heatdry & moist
Sterilization by heatSterilization by heatA. Dry heatA. Dry heat
Hot air oven:◦Electrically heated◦Thermostat◦Fan
Holding time:◦160° C 2hs◦180° C 1h
Used for:◦Glass◦Metals◦Dry material in sealed
container: oil, powder
PrecautionsGlass: good quality, dryObject put while oven is
coldHolding time:
calculated?Oven left to cool
Sterilization by heatSterilization by heatA. Dry heatA. Dry heat
Sterilization by heatSterilization by heatB. Moist heatB. Moist heat
1. Below 1001. Below 100°C°C
Sterilization by heatSterilization by heatB. Moist heatB. Moist heat2. At 1002. At 100°C°C
Sterilization by heatSterilization by heatB. Moist heatB. Moist heat2. At 1002. At 100°C°C
Sterilization by heatSterilization by heat B. Moist heat B. Moist heat
2. At 1002. At 100°C°C
Double walled metal cylinder
Lid: tightly fitted with clamps
Manometer: measure pr.Safety valve: exit of
excess heat when pr. Exceeds the required
Sterilization by heatSterilization by heat B. Moist heat B. Moist heat
3. Above 1003. Above 100°C°C (Autoclave) (Autoclave)
Principle (Heating under pressure)
Water is boiling at normal atmospheric pr. At 100°C
When pr to 2 atmospheric pr. temp. of water boiling (steam pr.) is 121°C
Temp.: 121°C at 2 atmospheric pr. for 20 min
Sterilization by heatSterilization by heat B. Moist heat B. Moist heat
3. Above 1003. Above 100°C°C (Autoclave) (Autoclave)
UsesSterilization of most
culture mediaSergical objects as:
dressings, towels, surgical instruments (scissors, clamps, arteries, retractors,…….)
Sterilization by heatSterilization by heat B. Moist heat B. Moist heat
3. Above 1003. Above 100°C°C (Autoclave) (Autoclave)
Hospital autoclavesHospital autoclaves
Wrapping of itemsWrapping of items
Tap with chemical indicator used Tap with chemical indicator used to verify sterilization processto verify sterilization process
Filtration
Principle◦Removal of bacteria from fluids
by passing them through filters with pores so small that bacteria are arrested.
Sterilization by Sterilization by filtrationfiltration
Sterilization by Sterilization by filtrationfiltrationUses
◦Preparation of soluble bacterial products as toxinstoxins.
◦Sterilization of liquids that would be damaged by heat as sera, antibiotics & vaccines.
Efficiency of the filtration:
retain Serratia marcescens average pore diameter 0.75 µm or less.
Seitz filters ◦Formed of asbestos with pore size 0.5-0.75µm.
◦Used for removing bacteria from serum and fluid culture media.
Sterilization by Sterilization by filtrationfiltrationTypesTypes
Membrane filters◦e.g. cellulose acetate-Millipore filter.
Disposable membrane filters Disposable membrane filters Left: a filter system designed for small volumes. Left: a filter system designed for small volumes. Right: a filter system designed for larger volumesRight: a filter system designed for larger volumes
Earthenware candlesEarthenware candles
Sintered filtersSintered filtersGlass filter
HEPA filter (High-efficient-particle-Arresters) Air sterilization ◦ICUs ◦OR◦isolation rooms. ◦safety cabinet in
microbiology labs
Irradiation
a)-Ultraviolet radiation: ◦Mercury lamp.Mercury lamp.
Uses: ◦Operating theatre. ◦Inoculation chamber
for viruses. ◦Water. ◦Killing of vaccines.
Sterilization by Sterilization by IrradiationIrradiationTypesTypes
Irradiation
b)- Ionizing irradiation (gamma rays) : ◦ Cobalt 60Cobalt 60.
Uses:
◦ Sterilization of an article an article not stand the heat not stand the heat as rubber catheters, cat gut or plastic syringes.
Low temperature sterilizationLow temperature sterilization
