sterilization & disinfection tukaram prabhu k asst professor microbiology pcms & rc
TRANSCRIPT
![Page 1: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/1.jpg)
Sterilization & Disinfection
Tukaram Prabhu KAsst ProfessorMicrobiologyPCMS & RC
![Page 2: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/2.jpg)
Lecture conducted for II yr MBBS (2008-2009 session)
• The following lecture is complied from different textbooks and is for teaching - learning use only
• This lecture is not a substitute for classroom lecture but an adjunct for the same
• This lecture may be useful for BSc Nursing, BMLT & DMLT students too
![Page 3: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/3.jpg)
DEFINITION
• The process of freeing an article or a surface from all living microorganisms including viruses & bacterial spores
• Various methods– Heat– Filtration– Radiation– Sterilant gases
![Page 4: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/4.jpg)
HEAT
• Factors affecting– Nature of heat – dry or moist– Temperature & time– No of organisms present– Characteristics of the organism– Type of material
• Two methods– Dry heat– Moist heat
![Page 5: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/5.jpg)
DRY HEAT
• Kills by oxidation, protein denaturation & toxic effect of elevated levels of electrolyte
• Types of processes– Flaming – Incineration – Hot air oven
![Page 6: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/6.jpg)
Dry heat - FLAMING
• 2500C – 3000C
• Points of forceps & Inoculation loops – heat in bunsen flame till red hot
• Slow passage through flame to destroy vegetative bacteria on surface of scalpel blade, glass slides, mouths of test tubes
![Page 7: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/7.jpg)
Flaming
![Page 8: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/8.jpg)
Dry heat - INCINERATION
• 8700C - 9800C
• Complete burning to ashes
• Used for soiled dressings, animal carcasses, pathological material, disposables, non-reusable soiled bedding
![Page 9: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/9.jpg)
Incineration
![Page 10: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/10.jpg)
Dry heat - HOT AIR OVEN
• Holding temp & time: 1600C for 1 hr• Used for glassware, forceps, swabs, water
impermeable oils, waxes & powders• Before placing in hot air oven
– Dry glassware completely– Plug test tubes with cotton wool– Wrap glassware in Kraft papers
• Don’t over load the oven• Allow free circulation of air between the material
![Page 11: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/11.jpg)
Dry heat - HOT AIR OVEN
• Sterilization controls: to check whether the equipment is working properly– Chemical controls: Browne’s tubes
• Color change from red to green
– Thermocouples– Biological controls: paper strips containing106 spores
of Clostridium tetani• Place strips in oven along with other material for the
sterilization • Later culture the strips in thioglycollate broth or RCM at 370C
for 5 days• Growth in medium indicates failure of sterilization
![Page 12: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/12.jpg)
Dry heat – Hot air oven
![Page 13: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/13.jpg)
MOIST HEAT
• Lethal effect due to denaturation & coagulation of proteins– Temp below 1000C– Temp at 1000C– Temp above 1000C
![Page 14: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/14.jpg)
Moist heat - Temp below 1000C
• Pasteurization • 630C – 30 min (Holder method)• 720C – 15-20 sec (Flash method)• 1320C – 1 sec (Ultra high temp)
• Vaccine baths - 600C – 60 min• For vaccines of non-sporing bacteria
• Water bath - 560C – 60 min – 3 days• For serum / body fluids containing coagulable proteins
• Inspissation – 80-850C – 30 min – 3 days• For media containing egg or serum – LJ, LSS
![Page 15: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/15.jpg)
• Inspissator Water bath
![Page 16: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/16.jpg)
Moist Heat - Temp at 1000C
• Boiling - 1000C for 10 min• Kills all vegetative bacteria• Water should be soft, deionized or distilled• 2% sodium bicarbonate promotes the process• Kills vegetative bacteria, hepatitis virus & some spores
• Steaming (free steam) – 30-60 min in Arnold /Koch steamer
– For heat labile media – DCA, TCBS
– Tyndallisation (intermittent sterilization) - 1000C, 30 min, 3 days
• Nutrient media & media containing sugars or gelatin• I day all vegetative bacteria are killed. On II & III day spores
that germinate are killed
![Page 17: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/17.jpg)
Moist Heat - Temp above 1000C
• Autoclave (steam under pressure) - 1210C, 15 min, 15 lbs– Used for rubber articles, dressings, sharp
instruments, infectious medical waste, culture media– Principle – (refer Ananthanarayan & Paniker 7th edn Page 27)
• Sterilization control– Thermocouples
– Browne’s tube (red-green), Bowie & Dick tape (white-brown)
– 106 spore of B stearothermophilus. Incubate at 550C for 5 days
![Page 18: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/18.jpg)
Moist Heat - Autoclave
![Page 19: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/19.jpg)
![Page 20: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/20.jpg)
Moist Heat - Autoclave
![Page 21: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/21.jpg)
Steam Jacketed Horizontal Autoclave
![Page 22: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/22.jpg)
FILTRATION
• Aqueous liquids may be sterilized by forced passage through a filter of porosity small enough to retain any microorganisms present in them
• Used to sterilize serum, carbohydrates soln, filtrates of toxins & bacteriophages, in water bacteriology, in examination of Schistosoma eggs
![Page 23: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/23.jpg)
FILTRATION
• Types of filters– Earthenware candles
• Unglazed ceramic & diatomaceous earth filters• Eg. Chamberland filters, Doulton filters
– Asbestos filter – Seitz, Carlson, Sterimat– Sintered glass filter– Membrane filters – cellulose nitrate, cellulose acetate,
polycarbonate, polyester filters– Pore size: 0.015 – 12 μm• HEPA filters – for large volumes of air
Sterilization control – bubble pressure test
![Page 24: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/24.jpg)
• Asbestos Filter holderEarthenware
filter
![Page 25: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/25.jpg)
• Sintered glass filter
![Page 26: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/26.jpg)
Membrane filters
![Page 27: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/27.jpg)
RADIATION
• 2 types– Non ionising –
• Infra Red radiation ( rapid mass sterilization of syringes, etc)• Ultra Violet radiation (enclosed areas)
– Ionising – Gamma, X ray, cathode ray
(plastics, syringes, oil, metal foils)– Sterilization controls
• Dosimeter – measures radiation dose• Colored discs• M radiodurans, B pumilus
![Page 28: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/28.jpg)
STERILANT GASES
• Ethylene oxide
• Formaldehyde
• Betapropiolactone– More efficient than HCHO
![Page 29: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/29.jpg)
DISINFECTION
• The process of freeing an article or a surface from all or some of the living microorganisms but not necessarily bacterial spores
• Strong disinfectants – for inanimate object
• Mild disinfectant (antiseptic) – superficial application on living tissue
![Page 30: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/30.jpg)
Factors affecting DISINFECTION
• Conc of disinfectant• Time of action• pH of the medium• Temperature• Nature & number of organisms• Presence of extraneous material• Others – hardness of water, relative
humidity
![Page 31: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/31.jpg)
Categories of disinfectants
1. Alcohol2. Aldehyde3. Ethylene oxide4. Dyes5. Halogens6. Phenolics7. Surface active agents8. Metallic salts9. Diguanides10. Amides
![Page 32: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/32.jpg)
ALCOHOL
• Ethanol, isopropyl alcohol– Skin antiseptics at 70%– Less sporicidal & virucidal activity– Denature bacterial proteins– Isopropyl alcohol better fat solvent, more bactericidal
and less volatile
– Methyl alcohol – to treat cabinets / incubators affected by fungal spores
– Others – benzyl alcohol, chlorbutol, phenylethanol
![Page 33: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/33.jpg)
ALDEHYDE
• Formaldehyde - 10% used– In aq. soln is virucidal, bactericidal, sporicidal– Used to fumigate wards, sick rooms, labs– Expose to ammonia to remove residual formaldehyde– Has pungent smell, irritant to skin, eyes, mucus memb & toxic
when inhaled
• Glutaraldehyde – less toxic, less irritant– Endotracheal tubes, metal instruments, polythene tubing
• Β propiolactone (BPL) – condensation product of ketane & formaldehyde – More efficient for fumigation but is carcinogenic– 0.2% generally used
![Page 34: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/34.jpg)
ETHYLENE OXIDE
• Highly inflammable, mixed with inert gases – CO2, N
• Especially for heart lung machines, respirators, sutures, syringes, dental equipments
![Page 35: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/35.jpg)
DYES
• Combine with nucleic acids
• Aniline dyes– Brilliant green, malachite green, crystal violet
• Acridine dyes– Proflavine, acriflavine, euflavine, aminacrine
• Skin & wound antiseptics
• Bacteriostatic, more active against GP bacteria
![Page 36: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/36.jpg)
HALOGENS
• Kills by oxidation• Iodine – 2.5% in 70% alcohol, Skin antiseptic• Iodophores (iodine + non-ionic surface active
agent) – betadine – non staining, less irritant, less toxic
• Chlorine – disinfect water supplies, swimming pools
• Sodium hypochlorite – 1% for HIV• Organic chloramines – antiseptic for wound
dressings
![Page 37: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/37.jpg)
PHENOLICS
• Carbolic acid – 2-5%– Powerful microbicidal, very corrosive– General purpose disinfectant in hospital
• Cresol, lysol
• Chloroxylenol, chlorophenol, hexachlorophane – less toxic, less irritant, less active, more readily inactivated by organic matter
![Page 38: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/38.jpg)
SURFACE ACTIVE AGENTS
• Disrupt cell memb, 4 main groups• Anionic surfactants – strong detergent
action, weak antimicrobial action• Non-ionic surfactants • Cationic surfactants – quaternary
ammonium compounds – cetrimide, benzalkonium chloride - bacteriostatic
• Amphoteric surfactants – both detergent & antimicrobial properties – Tego comps
![Page 39: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/39.jpg)
METTALIC SALTS
• Mercuric salts – ointments
• Silver salts – AgNO3 – to prevent infection of burns, ophthalmia neonatorum
• Copper salts – antifungal, antialgae – water reservoirs, swimming pools
![Page 40: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/40.jpg)
DIGUANIDES
• Chlorhexidine – burns, skin disinfection
• Picloxydine –hospital equipment, floors
![Page 41: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/41.jpg)
AMIDES
• Propamide
• Dibromopropamide
• Antiseptic cream, eye ointments
![Page 42: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/42.jpg)
TESTS FOR DISINFECTANTS
• To determine efficacy of disinfectants– Phenol Co-efficient method
• Rideal Walker test• Chick Martin test
– Compares disinfectant with phenol
– Kelsey & Sykes Capacity test– Determines dilution of disinfectant to be used
– Kelsey & Mauer In-use test (stability test)– Checks end result of disinfection
![Page 43: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/43.jpg)
• PRIONS• BACTERIAL SPORES Sterilisation• High Level Disinfection• Bacillus subtilis• Clostridium sporogenes Intermediate Level disinfection• MYCOBACTERIA•• M. tuberculosis var bovis•
NON LIPID OR SMALL VIRUSES Low Level Disinfection• Polio virus, Rhino virus• FUNGI• Trichophyton, Candida, Cryptococcus• VEGETATIVE BACTERIA• Pseudomonas, Staphylococcus, VRE• LIPID OR MEDIUM SIZED VIRUSES• HBV, HIV, HSV, HCV, EBOLA, CMV•
![Page 44: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/44.jpg)
Categories• Sterilisation
• High level disinfection (HLD) kills all microorganisms except high number of bacterial spores - aldehydes, hydrogen peroxide, ortho-phthaldehyde
• Intermediate level disinfection (ILD) kills all vegetative bacteria including M. tuberculosis var bovis, all fungi and most viruses - phenolics, iodophores, chlorine compounds, alcohols
• Low level disinfection (LLD) kills most vegetative bacteria but not M. tuberculosis var bovis, some fungi and some viruses - Hospital type germicides- quaternary ammonium compounds
![Page 45: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/45.jpg)
Plasma technology
• Glow discharge or low temperature plasmas
• Plasma has sufficient energy to disrupt molecular bonds
• Direct current, radiofrequency, microwave power is used to produce the plasma
• Used in disinfection of OTs
![Page 46: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/46.jpg)
A known HIV positive patient is admitted in an isolation ward after an abdominal surgery following an accident. The resident doctor who changed his dressing the next day found it to be soaked in blood. Which of the following would be the right method of choice of discarding the dressings :
a) Pour 1% hypochlorite on the dressing material and send it for incineration in a appropriate bag
b) Pour 5% hypochlorite on the dressing material and send it for incineration in a appropriate bag
c) Put the dressing material directly in an appropriate bag and send for incineration
d) Pour 2% Lysol on the dressing material and send it for incineration in a appropriate bag
![Page 47: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/47.jpg)
Heat labile instruments for use in surgical procedures
can be best sterilized by
• Absolute alcohol
• Ultra violet rays
• Cholorine releasing compound
• Ethylene oxide gas
![Page 48: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/48.jpg)
Sterilizing agents include
– Cyclohexidene– Ethylene oxide– Diethyl ether– Gallamine
![Page 49: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/49.jpg)
Sharp instruments are not sterilized by
• Dry heat
• Boiling
• 2% glutaraldehyde
• Autoclaving
![Page 50: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/50.jpg)
Which is a form of cold sterilization
• Gamma rays
• Beta rays
• IR rays
• Autoclave
![Page 51: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/51.jpg)
Sterilization of serum containing media
• Autoclaving
• Filtration
• Gamma radiation
• Incineration
![Page 52: Sterilization & Disinfection Tukaram Prabhu K Asst Professor Microbiology PCMS & RC](https://reader033.vdocuments.mx/reader033/viewer/2022061601/55189fd3550346881f8b4815/html5/thumbnails/52.jpg)
Sterilizing agents include
• Ether
• Alcohol
• Chlorhexidine
• Dry heat
• Ethylene oxide