Methods Of Sterilization Flashcards
Sterilization
Sterilization is defined as the process by which an article surface or medium is freed of all living microorganism either in the vegetative or spore state
Disinfection
Disinfection is the destruction of all pathogenic organism
Asepsis
Asepsis is a state of complete absence of viable pathogenic microorganisms in any environment
Antiseptic
Antiseptic are the agents that can be safely applied on the skin or mucous Memon to prevent infection by inhibiting the growth of bacteria
Bactiricidal agents
That can kill bacteria
Bacteriostatic agent
Bacterio static agents prevent the multiplication of bacteria which may however remain alive. A chemical which is bactericidal at a particular concentration may become bacterio static at higher dilution
Sterling agents
Physical agents are dry heat, moist heat, filtration, radiation
Chemical agents are alcohol, aldehyde, dyes, hydrogen peroxide, hypochlorus acid halogen, phenol, surface acting agent metallic salt.
Dry heat
Flaming- inoculating loops, wire, forceps
Incineration - biomedical waste
Hot air oven - 160c for two hours to sterilize glassware, forceps, scissors, syringe
150 for opthalmic
Moist heat
BELOW 100C
Pasteurisation of milk
Inspissation
AT 100C
Boiling
Steam at atmospheric pressure
Tyndalisation
Steam under pressure
Pasteurisation temp
Flash method 72c for 15-20sec
Holder method 63c for 30 mins
Tyndalisation
For media containing sugar and gelatin
100c for 20 mins x 3days
Tyndalisation
For media containing sugar and gelatin
100c for 20 mins x 3days
Autoclave
Temp 108c to 147c
For linen, instrument, laboratory waree, media
Type of filters
- Candle filters - unglazed ceramic eg chamberland and doultan
Diatomaceous earth eg Berkefeld and Mandler - Sinister glass
3 membrane
Properties of ideal disinfectant
- Have white spectrum of activity and be effective against all microorganisms
- Be active in the presence of organic matter
3.v be effective in acid as well as alkaline media - Have speedy action
- Has high penetrating power
- Be stable
Factors that affect the potency of a disinfectant
- Concentration of substance
- Contact period
- Ph of medium
- Temperature
- Nature of the organism
- Presence of extraneous material
Mode of action of chemical agent
- By protein coagulation
- By disruption of the cell membrane resulting in exposure damage or loss of content
- Bye removal sulphydryl group essential for the functioning of the enzyme
- By substrate competition
Alcohol
ETHYL - 60-90% conc
For denaturing bacterial proteins, no action on spores
METHYl - for fungal spores and cleaning cabinets and incubators
Aldehydes
1.FORMALDEHYDE - active against the amino group in the protein molecule it is used to preserve anatomical specimen. It is used for sterilizing instrument heat sensitive catheter and for fumigating wards isolation room and laboratory
2. GLUTARALDEHYDE - it is effective against tubercular bacilli fungi viruses it has no delete areas effect on cement or lenses of instrument
3.ORTHOPTHALALDHYDEHDE- IT IS USED TO CLEAN ENDOSCOPE BETWEEN PATIENT AS IT IS QUICK EFFECTIVE AND SAFE
4.PERACETIC ACID - common antibiotic assistant bacteria
5. HYPOCHLOROUS ACID- biofilms
Examples of aniline dye
Brilliant green
Malachite green
Crystal violet
Acts against tubercular bacilli
Iodine
It is a bactericidal with moderate action against spores
Aqueous and alcoholic solution has been widely used as skin disinfectant
Iodine
It is a bactericidal with moderate action against spores
Aqueous and alcoholic solution has been widely used as skin disinfectant
Phenols
Phenols- cresol and Lysol
Chlorhexidine for wound dressing
Ethylene oxide
Heart lung machine, respirators, suture material, dental equipments
