2. Sterilization: complete removal, destruction, inactivation of all forms of microbial lifeviruses,Fungi,bacteria,Spores.

3. Disinfection: elimination of most pathogenic organisms excluding sporicidal activity. There are 3 levels; HLD, all vegetating bacteria, MTB, fungi, all viruses ILD, all vegetating bacteria, MTB, majority of fungi, majority of viruses LLD, vegetating bacteria except MTB, some fungi, some viruses

4. Antiseptics: chemical disinfectants applied to skin, mm but not systemic Cleaning: removal of dust, dirt, organics, FM. Decontamination: general term applied to any procedure by which microorganisms are reduced to a level where items are safe to handle

5. Patient’s care items are divided into 3 categories: Critical items Semi-critical items Non-critical items Depending on the risk of infection due to their utilization

6. Critical Semi critical Noncritical Items enter -sterile tissues-cavities- vascular system e.g. needles, implants, catheters, surgical instruments Sterilization: EO, autoclave, plasma, sterilant Items come in contact with intact mm & non intact skin e.g. endoscopes, endotracheal tube, thermometer High level disinfectant, glutaraldehyde, chlorine active, hydrogen peroxide Items come in contact with intact skin e.g. sphygmomanometers, bed linens, floors Intermediate and low level disinfectants, alcohols, phenols

7. Decreasing order of resistance of microorganisms to disinfection and sterilization ResistantSusceptible Prions Prions Bacterial spores Bacterial spores Mycobacteria Mycobacteria Small non-enveloped viruses Small non-enveloped viruses Gram-negative bacteria Gram-negative bacteria Fungi Fungi Large non-enveloped viruses Large non-enveloped viruses Gram-positive bacteria Gram-positive bacteria Lipid enveloped viruses Lipid enveloped viruses

11. Decontamination Steps

12. I. Heat 1- Moist heat or steam sterilization 2- Dry heat sterilization II. Low temperature (cold): 1. chemical a. ethylene oxide b. liquid steriliants: GLD, PAA, H2O2 2- plasma sterilizer III. Other sterilizers: 1- ionizing radiation 2- filtration 3- microwaves; in pharmaceutical industries

13. Heat is the most practical, efficient, and inexpensive method of sterilization and disinfection of objects that can withstand high temperatures. Heat is the most practical, efficient, and inexpensive method of sterilization and disinfection of objects that can withstand high temperatures. There are two forms: There are two forms: –Moist heat is much more efficient than dry heat because: it kills microorganisms by coagulating and denaturing their enzymes and structural proteins it kills microorganisms by coagulating and denaturing their enzymes and structural proteins it is quicker in heating up the article to be sterilized. it is quicker in heating up the article to be sterilized. –Dry heat is believed to kill microorganisms by causing destructive oxidation of essential cell constituents.

14. Autoclave = saturated water steam under high pressure. heating water under controlled conditions in a closed vessel in order that boiling point of water rises above 100°C. Saturated steam carries the same temperature of boiling water. It is essential to make steam saturated and free of any residual air because air acts as an insulator, reduces temperature and hinders penetration. Sterilization temperature and exposure time : at 121°C for 20-30 minutes at double atmospheric pressure (2 bar) or at 134°C for 3-6 minutes (at 3 bar).

15. Steam sterilization is the most common and preferred method for sterilizing those items that can withstand high temperature and moisture, e.g. culture media, surgical instruments and dressings. Steam sterilization is the most common and preferred method for sterilizing those items that can withstand high temperature and moisture, e.g. culture media, surgical instruments and dressings.

16. Autoclave: Advantages: 1- Non-toxic 2- liberation of latent heat due to condensation of steam 3- Inexpensive 4- Rapidly microbicidal 5- Least affected by organic/inorganic soils 6- Rapid cycle time 7- Penetrates medical packing, device lumens Disadvantages: 1- Deleterious for heat labile instruments 2- Potential for burns not for powders and oils

17. Sterilization monitored routinely by combination of mechanical, chemical, and biological parameters Physical - cycle time, temperature, pressure Physical - cycle time, temperature, pressure Chemical - heat or chemical sensitive inks that change color when germicidal-related parameters present Chemical - heat or chemical sensitive inks that change color when germicidal-related parameters present Biological - Bacillus spores that directly measure sterilization (Geobacillus stearothermophilus) Biological - Bacillus spores that directly measure sterilization (Geobacillus stearothermophilus)

18. Chemical Indicators

20. I. Incineration: For dead animal bodies For dead animal bodies Infectious hospital waste Infectious hospital waste II. Red heat: for wires, loops, tips of forceps they are flamed till reach redness I. Hot air oven: Dry hot air used either 170c for 60 min 170c for 60 min or 160c for 120 min Micro-incinerator

21. Hot air oven Hot air oven - They are electrical devices used in sterilization. -There is a digitally controlled thermostat controlling the temperature. - Their double walled insulation keeps the heat in. - There is also an air filled space in between to aid insulation. - An air circulating fan helps in uniform distribution of the heat.

22. Advantage of dry heat 1. Hot air penetrates certain substances that cannot be steam sterilized (oil, powder). 2. Dry heat can be used in laboratories to sterilize glassware 3. Dry heat is a protective method of sterilizing no erosion or corrosion. 4. Instruments that cannot be disassembled may be sterilized in hot air. 5. Low cost Disadvantages of dry heat 1. A long exposure period is required because hot air penetrates slowly possibly unevenly. 2. Time and temperature vary for different substances. 3. Over exposure may ruin some substances. 4. It is destructive to fabrics and rubber goods Monitored by B.subtilis spores

23. Ethylene oxide gas is commonly used to sterilize objects sensitive to temperatures greater than 60 °C such as plastics, optics and electrics. Ethylene oxide gas is commonly used to sterilize objects sensitive to temperatures greater than 60 °C such as plastics, optics and electrics. Ethylene oxide penetrates well, moving through paper, cloth, and some plastic films and is highly effective. Ethylene oxide penetrates well, moving through paper, cloth, and some plastic films and is highly effective. Ethylene oxide sterilizers are used to process sensitive instruments which cannot be adequately sterilized by other methods Ethylene oxide sterilizers are used to process sensitive instruments which cannot be adequately sterilized by other methods

24. Advantages Advantages –Very effective at killing microorganisms –Penetrates medical packaging and many plastics –Compatible with most medical materials not withstanding heat –Cycle easy to control and monitor Disadvantages Disadvantages –Some states require ETO emission reduction of 90-99.9% –(inert gas that eliminates explosion hazard) banned after 1995 as it is inflammable –Potential hazard to patients and staff (very toxic and carcinogenic in animal models) –Lengthy cycle (3-6 hrs)/aeration time (18-24hrs) Monitored by B. subtilis spores

26. Plasma describes any gas that consists of electrons, ions, or neutral particles. Plasma sterilizers with the use of liquid peracetic acid, or hydrogen peroxide, or a mixture of both are commercially available. The energy used is either microwave frequency or radio-frequency.

28. 1- Gamma rays (Co-60). 2-High energy electrons (electron accelerator). This process does not result in rise in temp; but the time required for sterilization is long (48hrs). High penetration power so used in prepacked items, as gloves, syringes, plastic IV lines,… Monitored by B.pumilus spores

29. Sterilization of fluids which would not withstand heat such as antibiotic solutions, blood products, hormones, vitamins….etc. Sterilization of fluids which would not withstand heat such as antibiotic solutions, blood products, hormones, vitamins….etc. Fluids can be rendered free of bacteria by passage through filters with a pore size of less than 0.45 µm. Fluids can be rendered free of bacteria by passage through filters with a pore size of less than 0.45 µm. –However, most viruses and certain bacteria as mycoplasma can pass through filters with a pore size as small as 0.22 µm.

30. Filtration: Fluids

31. Early filters made from glass and asbestos Early filters made from glass and asbestos – largely replaced by membrane filters made of cellulose esters or other polymers. Membrane filters are preferred because: Membrane filters are preferred because: – they filter more rapidly. – they don't affect the filtrate in any way. – they adsorb very little of the substance being filtered. – The endopigment producing Serratia marcescens can be used to test the efficiency of bacterial filters. The endopigment producing Serratia marcescens can be used to test the efficiency of bacterial filters.

32. Filters can be used to remove microorganisms from air supplied to critical areas such as operating rooms, drug factories and laminar flow ventilation system. Filters can be used to remove microorganisms from air supplied to critical areas such as operating rooms, drug factories and laminar flow ventilation system. A properly installed high efficiency particulate air (HEPA) filter can achieve 99.997% arrest to particles ≥ 0.5 µ m, and can produce sterile air. A properly installed high efficiency particulate air (HEPA) filter can achieve 99.997% arrest to particles ≥ 0.5 µ m, and can produce sterile air. Spores of the fungus Aspergillus can be used to test the efficiency of HEPA filters. Spores of the fungus Aspergillus can be used to test the efficiency of HEPA filters.

33. Filtration: Air

34. 1- Chemical disinfection 1- Chemical disinfection 2- Boiling water 3- Pasteurization 4- Ultraviolet irradiation

35. 1- Alcohol 70% (ethyl and isopropyl): Exposure time: 5 min at least Uses: 1- disinfection of a. external surfaces b. non invasive instruments 2- skin antiseptic, alone or added to iodine or chlorhexidine 2- Biguanides (chlorhexidine): 1- antiseptic for skin and mm, mouth wash (hexitol) 2- combined with. Alcohol as hand rub. Detergent as hand wash

36. 3- Chlorine- active compounds (hypochlorite, house hold bleach): 1- decontamination of blood splashes and lab. Working surfaces (100-1000ppm) 2- linen bleaching 2- linen bleaching 3- disinfection of water 4- Iodine based compounds (most effective antiseptics): include - tincture iodine (iodine in alcohol), staining and irritant - iodophores (iodine with neutral carrier), slow release of free iodine, more penetration, no staining and not irritant, betadine (30-50ppm) - iodophores (iodine with neutral carrier), slow release of free iodine, more penetration, no staining and not irritant, betadine (30-50ppm) used as skin antiseptic in surgical scrubbing and before surgery. Both halogens exert their bactericidal action by irreversible oxidation of the essential enzymes by the free radicals

37. 5- Phenol containing preparations (phenol\lysol) ILD: Used for floors, walls and furniture Hexaphenol (detol) was used as antiseptic, was proven to cause neurological damage 6- Quternary ammonium compounds LLD: detergent either.anionic as soap or. Cationic as LLD.Used for routine cleaning of walls, floors or furniture. 7- Hydrogen peroxide: (oxidizing agent) HLD& sterilants 1- antiseptic for open wounds( kill anaerobes) 2-disinfection of soft contact lenses, some endoscopes 8- Peracetic acid: (oxidizing agent) HLD& sterilants HLD, strilizant of instruments as endoscopes 9- Glutaraldehyde(cidex) and Formaldehyde HLD& sterilants: GLD: HLD, sterilizant of instruments as endoscopes, respiratory and anaesthesia equipments FLD: gas not used now, found to be carcinogenic, only used in sterilization of HEPA filters.

38. Boiling at 100c for 20 min = HLD Only in emergencies It is heating at temperature less than 100c 1- Pasteurization of milk: heating at 63c for 30 min or at 72c for 20 sec, this is followed by rapid cooling. this destroys imp pathogenic bacteria as, MTB, salm, brucella, coxiella 2- Pasteurization of water: heating at 77c for 30 min. used for disinfection of items can ’ t withstand higher temp it may be coupled with chemical disinfection to achieve higher level of disinfection or even sterilization

39. UV is a low energy, non ionizing irradiation Its present in sun, artificially produced by mercury lamps Over exposure may cause eye damage and skin irritation Have extremely weak penetration power Used only for: Air and surface disinfection in Operating rooms Safety cabinet