4Key points - 1Cleaning, disinfection, and sterilisation are the backbone of infection prevention and controlProper cleaning essential before any disinfection or sterilisation processFailure to sterilise or disinfect reusable medical devices properly may spread infectionsThe type and level of device decontamination depends upon the nature of the item and its intended useDecember 1, 2013
5Key points - 2 Steam sterilisation effective only when preceded by Thorough pre-cleaning, proper packaging/loading, and careful monitoring of autoclavesChemical disinfectants must be selected, used, and discarded to minimise harmThose responsible for processing contaminated items must be fully trained and wear protective clothing when necessaryClearly written policies and procedures must be available on-site for training personnel and for monitoring their performanceDecember 1, 2013
6DecontaminationA process of treatment that renders a medical device, instrument, or environmental surface safe to handleDoes not necessarily mean that the item is safe for patient reuseDecember 1, 2013Decontamination is the combination of processes (including cleaning, disinfection and sterilisation) used to render items safe for handling by staff and for use on patients. Effective decontamination is an essential component in the prevention of healthcare associated infection. Decontamination methods used will depend on the nature of the micro-organisms present and the infection risk associated with the surface, equipment, device or procedure.Re-usable medical devices must be decontaminated between each patient use by the user to prevent cross infection using a risk assessment model. Use only the decontamination methodadvised by the manufacturer - using any other process might invalidate warranties and transfer liability from the manufacturer to the person using or authorising the process. If there are anydoubts about the manufacturer’s recommendations, seek further advice. Reusable items must be disassembled safely and cleaned as soon as possible after use to prevent any contaminants from drying.
7Pre-Cleaning/Cleaning Everyone responsible for handling and reprocessing contaminated items must:Receive adequate training and periodic retrainingWear appropriate personal protective equipment (PPE)Receive adequate prophylactic vaccinationsDecember 1, 2013Cleaning is the first step in the decontamination process. While ‘cleaning’ means to get rid of visible dirt, ‘pre-cleaning’ refers to the removal of body fluids and other contamination before disinfection or sterilisation. Proper pre-cleaning can substantially reduce the pathogen load while removing organic and inorganic residues to facilitate reprocessing. Thorough pre-cleaning is vital for successful disinfection and sterilisation.Effective cleaning and pre-cleaning of devices often requires chemicals, combined with mechanical action and heat. It can be performed manually and/or with machines. Any equipment used must be regularly checked and maintained. There are a number of factors that determine the efficiency of the cleaning process, including the following:Type and amount of soilQuality of waterType of detergentConcentration of detergentType of instrument or deviceAmount of time permitted for the detergent to actReusable items may be cleaned by hand, by use of mechanical equipment, or a combination of the two methods. Manual cleaning requires detergents or enzymes with friction (rubbing, brushing, flushing) to remove soil from the outside and inside of the items being reprocessed. The use of mechanical equipment can improve cleaning effectiveness, increase productivity, and promote employee safety. Various types of mechanical cleaning equipment are available such as washer disinfectors, ultrasonic cleaners and cart washers, and the equipment should be selected to meet the health care facility’s needs.
8Spaulding Classification Divided hospital instruments into general categories based on the risk of infection involved in their useCritical itemsSemi critical itemNon critical itemsDecember 1, 2013In 1968, Dr. EH Spaulding classified medical/surgical devices as: critical, semi-critical and non-critical based on their potential to spread infections.While the Spaulding classification system remains useful, it needs adjusting to suit current requirements. Prions with their unusual resistance to many physical and chemical agents and the emergence of the spore-former Clostridium difficile as a healthcare-associated pathogen, are forcing a re-examination of medical device reprocessing. Prion-contaminated devices require sterilisation protocols well beyond those in normal use. Some disinfectants (e.g., glutaraldehyde) normally used to reprocess gastrointestinal endoscopes need prolonged contact times to kill C. difficile spores. Heat-sensitive devices such as flexible fibreoptic endoscopes are increasingly being used for operations in which the integrity of a mucous membrane is deliberately breached, thus blurring the line between ‘critical’ and ‘semi-critical’.
9Critical ItemsEnter normally sterile tissues, the vascular system, or equipment through which blood flowsItems must be properly and safely pre-cleaned and sterilised before useDecember 1, 2013Critical items enter normally sterile tissues, the vascular system, or equipment through which blood flows; for example: surgical instruments and vascular catheters. These items must be properly and safely pre-cleaned and sterilised before use.
11Semi-critical ItemsContact mucous membranes but do not penetrate soft tissue or body surfacesMeticulous physical cleaning followed by appropriate high-level disinfectionDecember 1, 2013Semi-critical items come into contact with intact mucous membranes or non-intact skin; flexible fibreoptic endoscopes, vaginal probes, and respiratory therapy equipment are examples. These items require proper pre-cleaning and, at a minimum, high-level disinfection before use.
13Non Critical ItemsDirect contact with the patients intact skin (unbroken skin)Little risk of pathogen transmission directly to patientClean and disinfect using a low to intermediate level disinfectantDecember 1, 2013Noncritical instruments and devices only contact intact (unbroken) skin, which serves as an effective barrier to microorganisms. These items carry such a low risk of transmitting infections that they usually require only cleaning and low-level disinfection. However, if an item is visibly bloody, it should be cleaned and disinfected using an intermediate-level disinfectant before use on another patient.Examples of instruments in this category include X-ray head/cones, facebows, pulse oximeter, and blood pressure cuff.
14Examples of Non Critical Items Items which are in contact with intact skinBedpansBlood pressure cuffsCrutchesStethoscopesFace maskX-ray machineDecember 1, 2013Most environmental surfaces in patient rooms and throughout a health care facility are non-critical and do not require routine disinfection. However, high-touch surfaces, particularly those in a patient’s immediate surroundings that might come in contact with the patient, need regular cleaning to prevent the transfer of pathogens to hands. Currently, there are no generally accepted guidelines regarding: if, when, how, and how often such surfaces are to be cleaned.
15DisinfectionA process that eliminates many or all pathogenic microorganisms on inanimate objects, with the exception of bacterial sporesDecember 1, 2013Disinfectants are substances that are applied to non-living objects (e.g., instruments) to destroy microorganisms that are living on the objects. ‘Disinfection’ means to reduce the number of pathogens on an inanimate surface or object using heat, chemicals, or both.Most disinfection procedures have little activity against bacterial spores; any reduction in the spore load is mainly achieved by mechanical action during cleaning and flushing with water.
16Sterilisation - 1The complete elimination or destruction of all forms of microbial lifeIncludes large numbers of highly resistant bacterial sporesDecember 1, 2013Sterilisation is any process that can inactivate all microorganisms in or on an object. Heat is the most reliable sterilant; most surgical instruments are heat-resistant. Heat-sensitive items require low-temperature sterilisation; ethylene oxide (EO) gas, hydrogen peroxide gas-plasma, and steam-formaldehyde are often used for this purpose.Used for items that will contact broken skin or mucous membranes or will penetrate the skin or enter sterile body areas.Routine sterilisation procedures may require modifications to address prions.
17Sterilisation - 2 Store in clean, dry place Protect wrapping Inspect before useDecember 1, 2013Sterilised items must be stored in a clean, dust-free, and dry place and the integrity of the wrapping must be protected. Packages containing sterile supplies should be inspected before use to verify barrier integrity and dryness. If packaging is compromised, the items should not be used and instead cleaned, wrapped, and resterilised.All reprocessed items must be stored properly to prevent damage or recontamination.
18Staff Training and Protection Written and up-to-date policies and procedures must be available on-site for training/monitoring staff responsible for device reprocessingTrain staff fully and retrain as necessary; maintain written recordsThe staff must also be provided with:Personal protective equipment (PPE)Prophylactic vaccinationsDecember 1, 2013Topics might include:DecontaminationChemical DisinfectionPreparation and Handling of Surgical InstrumentsPreparation and Packaging for SterilizationSterilization; steam, dry heat, ethylene oxide gas, low temperature gas plasma, peracetic acidSterile Storage
19Single-Use Items Single-use items must be safely discarded after use e.g., injection needlesNo reprocessing before carefully considering the following:Is device undamaged and functional?Can it be disassembled for reprocessing?Can its sterility be validated, if needed?Is the reprocessing cost-effective?Is an authorised person onsite willing to be responsible for any negative consequences?December 1, 2013Single-use items are not designed for reprocessing; manufacturers will not guarantee safety and performance after reprocessing these items. If reprocessing is contemplated, satisfactory answers are required for the following questions.Is the device undamaged and functional?Can the device be disassembled for cleaning, decontamination, and further processing?Can its sterility be validated, if needed?Is the reprocessing cost-effective?Is a person of authority at the site available and willing to take responsibility for any negative consequences from the use of the reprocessed item?
20Choice of Method Method to be used will depend on: Device’s intended useRisk of infectionDegree of soilageProcess must not damage the deviceDecember 1, 2013Practical tips for using water for cleaning, disinfection and sterilisationUse clean water (preferably filtered or boiled) for cleaning, disinfecting and sterilising.In areas where tap water and surface water have a high mineral or salts content use clean (filtered or boiled) rainwater for cleaning, preparing disinfection solutions and sterilising. Water with a high mineral or salts content can damage equipment and instruments causing scaling, furring and corrosion of boilers and sterilisers. Boiling or filtering does not reduce the mineral or salts content of water but will ensure that the water is clean.Use cool or warm water for cleaning not hot water. Hot water causes protein substances (such as organic matter) to stick to instruments and equipment.
21DisinfectionReduction in numbers of pathogens on inanimate surfaces/objectsFor items that will contact intact skin or mucous membraneUse physical or chemical agents or bothLevel of disinfectionHigh-levelIntermediate-levelLow-levelDecember 1, 2013Common chemical disinfectants include alcohols, chlorine and chlorine compounds, glutaraldehyde, ortho-phthalaldehyde, hydrogen peroxide, peracetic acid, phenolics, biguanides, and quaternary ammonium compounds (QAC). Such chemicals can be used alone or in combination. They must be used in accordance with the manufacturer’s instructions and only on surfaces with which they are compatible.Ideally, commercial products should pass standard tests to support label claims before being sold for use in health care settings. However, requirements for product registration and allowable label claims vary widely from region to region. This not only interferes with global harmonisation, it also makes testing products prohibitively expensive.There are often serious disparities between what is claimed on the product label and its actual use. For example, the recommended contact time for environmental surface disinfectants is usually much too long for practical use. Chemical disinfectants vary widely in the harm they can cause to humans and the environment, so must be used carefully, and only when no suitable alternatives are available.Disinfectants are placed into three categories depending on microbicidal activity – high-level, intermediate-level & low-level. Not all regions use this terminology.Proper disinfection depends on using an appropriate disinfectant at the right concentration and for adequate contact time. It is also important to follow the manufacturer’s instructions for disinfectant handling, preparation, use and storage. Incorrect dilution, poor storage and repeated use of the same working solution reduce the effectiveness of chemical disinfection. Choose disinfectants with the following characteristics:• Wide range of activity• Not readily inactivated• Non-corrosive when diluted• Non-irritant to skin• Low cost
22High-level Disinfectants - 1 Active against vegetative bacteria, viruses (including the non-enveloped ones), fungi, and mycobacteriaMay have some activity against bacterial sporesWith extended contact timesHLDs are used to disinfect heat-sensitive and semi-critical devicesSuch as flexible fibreoptic endoscopesDecember 1, 2013High-level disinfectants (HLD) are active against vegetative bacteria, viruses (including the non-enveloped ones), fungi, and mycobacteria. It may also have some activity against bacterial spores with extended contact times. HLDs are used to disinfect heat-sensitive and semi-critical devices such as flexible fibreoptic endoscopes.Aldehydes (glutaraldehyde and ortho-phthalaldehyde) and oxidisers (e.g., hydrogen peroxide and peracetic acid) are HLDs. The aldehydes are non-corrosive and safe for use on most devices. However, they can fix organic materials, therefore it is particularly important to remove any embedded microbes prior to disinfection.Unless properly formulated and carefully used, oxidisers can be corrosive. However, they can be faster-acting, non-fixative and safer for the environment than aldehydes.
23High-level disinfectants - 2 HLDs typically require minutes contact timeDepends on the temperatureAfter disinfection, items require thorough rinsing/flushing with sterile or filtered water to remove any chemical residuesThey must then be dried with an alcohol rinse or by blowing clean, filtered air through the device’s channels prior to storageDecember 1, 2013HLDs typically require minutes contact time for disinfection, depending on the temperature. After disinfection, items require thorough rinsing with sterile or filtered water to remove any chemical residues; they must then be dried with an alcohol rinse or by blowing clean and filtered air through the device’s channels prior to safe storage. Dry well and store properly to prevent damage or recontamination.
24Intermediate-level Disinfectants Active against vegetative bacteria, mycobacteria, fungi and most virusesMay fail to kill spores, even after prolonged exposureDecember 1, 2013A disinfectant active against vegetative bacteria, mycobacteria, fungi and most viruses. It may fail to kill spores, even after prolonged exposure.
25Low-level Disinfectants Active against vegetative bacteria (exceptmycobacteria), some fungi, and only enveloped virusesIn many cases, washing with unmedicated soap and water would be sufficient in place of LLDDecember 1, 2013Low-level disinfectants (LLD) are active against vegetative bacteria (except mycobacteria), some fungi, and only enveloped viruses. In many cases, washing with unmedicated soap and water would be sufficient in place of LLD.
26Chemical disinfectants in health care AgentsSpectrumUsesAdvantagesDisadvantagesAlcohols (60-90%) includingethanol and isopropanolLow- to intermediate-level disinfectant.Used for decontaminating the outside of some semi-critical and noncritical items, e.g., oral and rectal thermometers and stethoscopes. Also to disinfect small surfaces such as rubber stoppers of multi-dose vials. Alcohols with detergent are safe and effective for spot disinfection of countertops, floors, and other surfaces. Also common in handrubs.Fast acting.No residue.Non-staining.Low cost. Widely available in many countries for medicinal and research purposes.Volatile, flammable, and an irritant to mucous membranes.Inactivated by organic matter.May harden rubber, cause glue to deteriorate, or crack acrylate plastic.December 1, 2013Alcohols (ethyl and isopropyl alcohol) are rapidly bactericidal, tuberculocidal, fungicidal and virucidal, but not sporicidal. They denature protein through dehydration. The optimum concentration is 60-90% by volume. Alcohol is used to:• disinfect the surface of ampoules/vials prior to access• disinfect cleaned surfaces (following initial clean with detergent and water) e.g., trolleys, counter tops, laboratory benches where required• disinfect surfaces of some equipment e.g., stethoscope diaphragm, resuscitation manikins• assist in the drying of some equipment surfaces• disinfect skin prior to invasive procedures (refer to ‘skin antisepsis’)Comments:evaporates at room temperature. The concentration of alcohol diminishes as it evaporates and the action may be bacteriostatic at concentrations below 50%flammable at concentrations recommended for disinfection; precautions are required to prevent accidental ignition; unsuitable for use in operating roomsinactivated by organic material; prior cleaning is requiredinexpensive and readily availablethere is no residual activity after the alcohol has completely evaporatedgenerally unsuitable for application to mucous membranesdamages materials such as rubber, plastics. The lens cement of optical equipment is weakened by disinfection with alcoholic solutions.
27Chemical disinfectants in health care AgentsSpectrumUsesAdvantagesDisadvantagesChlorine and chlorine compounds: the most widely used is an aqueous solution of sodium hypochlorite % (domestic bleach) at a concentration of ppm free chlorineLow- to high-level disinfectant.Used for disinfecting tonometers and for spot disinfection of countertops and floors. Can be used for decontaminating blood spills. Concentrated hypochlorite or chlorine gas is used for disinfection of large and small water distribution systems, such as dental appliances, hydrotherapy tanks, and water distribution systems in haemodialysis centres.Low cost, fast acting. Readily available in most settings. Available as liquid, tablets or powders.Corrosive to metals in high concentration (>500 ppm). Inactivated by organic material.Decolourises or bleaches fabrics. Releases toxic chlorine gas when mixed with ammonia. Irritant to skin and mucous membranes.Unstable if left uncovered, exposed to light, or diluted; store in opaque container.December 1, 2013Chlorine (sodium hypochlorite)Sodium hypochlorite has broad spectrum antimicrobial activity; however it is inactivated in the presence of organic matter. It is used for the treatment of water, disinfection of laundryitems, dental appliances and clean environmental surfaces.Comments:• sodium hypochlorite is inactivated by organic material; prior cleaning is required for chlorine compounds to be effective• low concentrations of sodium hypochlorite are effective and rapidly disinfect clean surfaces• hypochlorite solutions may bleach and damage the texture of fabrics and corrode or damage materials e.g., stainless steel instruments and utensils• solutions are unstable; are to be prepared fresh for use and to be used within 24 hours• requires direct contact with surfaces (unsuitable for channels/crevices, etc.) for up to a maximum of 10 minutes• affected by temperature and water pH • concentration of chlorine-based disinfectants refers to available chlorine, which is a measure of oxidising power. The available chlorine content of aconcentrated solution is expressed as percent w/v or, part per million (ppm). One percent corresponds to 10,000 ppm available chlorineAvailable Chlorine (parts per million)10,000ppm 5000ppm 1000ppm 500ppm 125ppmHousehold bleach* 1:5 1:10 1:50 1:100 -*Household bleach (5%+ sodium hypochlorite) = 50,000 ppm available chlorine
28Chemical disinfectants in health care AgentsSpectrumUsesAdvantagesDisadvantagesAldehydesGlutaraldehyde: ≥2% alkaline or acidic solutions. Also formulated with phenol-sodium-phenate and alcohol.High-level disinfectant.Widely used as high-level disinfectant for heat-sensitive semi-critical items such as endoscopes.Good material compatibility.Allergenic and irritating to skin and respiratory tract. Must be monitored for continuing efficacy levels when reused.December 1, 2013GlutaraldehydeGlutaraldehyde is a liquid disinfectant recommended for the purposes of high level disinfection of heat-sensitive endoscopic instruments.Comments:• refer to manufacturers directions as products differ in relation to activation, duration of use and monitoring of in-use concentration• care must be taken to avoid the introduction of organic material or excess water by unclean or wet instruments which will reduce the concentration of glutaraldehyde• aldehydes fix protein to instrument surfaces; meticulous cleaning must occur prior to immersion• workplace health and safety issues are well-documented
29Chemical disinfectants in health care AgentsSpectrumUsesAdvantagesDisadvantagesOrtho-phthalaldehyde (OPA) 0.55%High-level disinfectant.High-level disinfectant for endoscopes.Excellent stability over wide pH range. Superior mycobactericidal activity compared to glutaraldehyde. Does not require activation.Expensive. Stains skin and mucous membranes; may stain items not thoroughly cleaned. Eye irritation. Poor sporicide. Must be monitored for efficacy during reuse. Contraindicated for reprocessing certain urological instruments.December 1, 2013Ortho-phthalaldehyde (OPA)Ortho-phthalaldehyde (OPA) is an instrument grade liquid disinfectant recommended for the purposes of high level disinfection of heat sensitive instruments. The increased level of microbial activity of ‘OPA’ lends itself to shorter disinfection immersion times than other available high level chemical disinfectants.‘OPA’ (0.55%) is a high level disinfectant suitable for reprocessing clean, heat sensitive, semi-critical medical and dental devices. It does not sterilize devices; items requiring sterilisation should undergo an appropriate, biologically monitored sterilisation process.Comments:• stable over a wide pH range• does not fix proteinaceous material to instruments• is compatible with a wide range of instrument models and materials• does not require activation• non-irritating to personnel• stains skin and surfaces• costly in comparison to glutaraldehyde
30Chemical disinfectants in health care AgentsSpectrumUsesAdvantagesDisadvantagesPeracetic acid % and other stabilised organic acids.High-level disinfectant/sterilant.Used in automated endoscope reprocessors. Can be used for cold sterilisation of heat-sensitive critical items, e.g., haemodialysers. Also suitable for manual instrument processing when properly formulated.Rapid sterilisation cycle time at low temperature (30-45 min. at 50-55oC). Active in presence of organic matter. Environmentally-friendly by-products (oxygen, water, acetic acid).Corrosive to some metals.Unstable when activated. May be irritating to skin, conjunctivae and mucous membranes.December 1, 2013Peracetic, or peroxyacetic, acid is characterized by a very rapid action against all microorganisms. A special advantage of peracetic acid is it has no harmful decomposition products (i.e., acetic acid, water, oxygen, hydrogen peroxide) and leaves no residue. It remains effective in the presence of organic matter and is sporicidal even at low temperatures. Peracetic acid can corrode copper, brass, bronze, plain steel, and galvanized iron but these effects can be reduced by additives and pH modifications. It is considered unstable, particularly when diluted; for example, a 1% solution loses half its strength through hydrolysis in 6 days, whereas 40% peracetic acid loses 1 to 2% of its active ingredients per month. It is used in automated machines to chemically sterilize medical, surgical, and dental instruments (e.g., endoscopes, arthroscopes).
31Chemical disinfectants in health care AgentsSpectrumUsesAdvantagesDisadvantagesHydrogen peroxide 7.5%.High-level disinfectant/sterilant.Can be used for cold sterilisation of heat-sensitive critical items. Requires 30 minutes at 20oC.No activation. No odour.Environmentally-friendly by-products (oxygen, water).Not compatible with brass, copper, zinc, nickel/silver plating.Hydrogen peroxide 7.5% and peracetic acid 0.23%For disinfecting haemodialysers.Fast-acting (high-level disinfection in 15 min.). No activation required. No odour.Not compatible with brass, copper, zinc, and lead. Potential for eye and skin damage.December 1, 2013Hydrogen peroxide provides high level disinfection in 30 minutes at 20 degrees Celsius. Stabilized hydrogen peroxides can be used to disinfect environmental surfaces. Stabilized hydrogen peroxides can be used to disinfect environmental surfaces.Peracetic acid is part of the family of peryoxygen compounds. A concentration of 0.2% peracetic acid is rapidly active against all microorganisms including bacterial spores, and is effective in the presence of organic matter. It has proved to be an acceptable alternative to EtO. The combination of peracetic acid and hydrogen peroxide has been used for disinfecting hemodialysers. Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (0.08 peracetic acid plus 1.0% hydrogen peroxide [no longer marketed], 0.23% peracetic acid plus 7.35% hydrogen peroxide).
32Chemical disinfectants in health care AgentsSpectrumUsesAdvantagesDisadvantagesPhenolicsLow- to intermediate-level disinfectant.Has been used for decontaminating environmental surfaces and non-critical items. Concerns with toxicity and narrow spectrum of microbicidal activity.Not inactivated by organic matter.Leaves residual film on surfaces. Harmful to the environment. No activity against viruses. Not recommended for use in nurseries and food contact surfaces.December 1, 2013PhenolicsPhenolics are classified as low level disinfectants. They are absorbed by porous materials, and the residual disinfectant may cause tissue irritation. Phenolics are bactericidal, virucidal, fungicidal and tuberculocidal.Comments:• mainly used for environmental disinfection of non-porous surfaces, such as laboratory surfaces• not for routine hospital use
33Chemical disinfectants in health care AgentsSpectrumUsesAdvantagesDisadvantagesIodophores (30-50 ppm free iodine)Low-level disinfectant.Used on some non-critical items, e.g., hydrotherapy tanks; however, main use is as an antiseptic.Relatively free of toxicity or irritancy.Inactivated by organic matter. Adversely affects silicone tubing. May stain some fabrics.Quaternary ammonium compoundsLow-level disinfectant unless combined with other agents.Used mainly on environmental surfaces. Can be used on skin.Stable with good detergent properties (cationic detergent). Usually non-irritating.Relatively narrow microbicidal spectrum, but range of activity can be expanded when combined with other agents, e.g., alcohols.December 1, 2013Iodine solutions or tinctures long have been used by health professionals primarily as antiseptics on skin or tissue. Iodophors, on the other hand, have been used both as antiseptics and disinfectants. Iodine can penetrate the cell wall of microorganisms quickly, and the lethal effects are believed to result from disruption of protein and nucleic acid structure and synthesis.Besides their use as an antiseptic, iodophors have been used for disinfecting blood culture bottles and medical equipment, such as hydrotherapy tanks, thermometers, and endoscopes.Quaternary ammonium compounds – these compounds are not effective against some Gram-negative bacteria, including those that are antibiotic-resistant. Suitable for low-level disinfection of clean surfaces; not recommended for routine use in health care facilities. Cement, synthetic rubbers and aluminum may be damaged by quaternary ammonium compounds, especially if an anti-rust compound has been added to the solution. Inactivated in the presence of organic matter.
34Practical Tips - 1 Develop a policy for chemical disinfection Disinfectants may be supplied ready to use or may need to be dilutedLabel bottles or containers with the name and concentration of disinfectant and, for diluted disinfectants, the date of dilution/preparationPrepare dilutions with clean waterPrepare small amounts at a time to avoid wastageDecember 1, 2013From the WHO:
35Practical Tips - 2Do not mix freshly made diluted solution with old solutionWash and dry the container before filling with new solutionClean, rinse and dry items thoroughly before disinfectingAfter disinfection, rinse thoroughly with clean water to remove all chemical residuesAlcohol solutions can be allowed to dry without rinsingDecember 1, 2013From the WHO:All disinfectants are inactivated to some extent by organic matter, rubber, hard water and detergents. Use fresh soaking solution every day. Renew soaking solution during the day if it looks dirty. Never mix fresh solution with old solution. Wash and dry the container before filling with new solution. Avoid soaking metal items for too long or in too high concentrations as this causes corrosion and rusting.
36Steam SterilisationRequires direct contact of an item with steam at a required temperature and pressure for a specified timeMost reliableNon-toxicHas broad-spectrum microbiocidal activityGood penetrating abilityCheap and easy to monitor for efficacy2 main types: gravity and pre-vacuumDecember 1, 2013Steam is the most reliable means of sterilisation. It is non-toxic (when generated from water free of volatile chemicals), has broad-spectrum microbicidal activity, and good penetrating ability, while being cheap and easy to monitor for efficacy. Sterilisation requires direct contact of an item with steam at a required temperature and pressure for a specified time. Autoclaves are specially designed chambers in which steam under pressure produces high temperatures. They are based on the same principle as pressure-cookers. There are two main types of steam sterilisers - gravity and pre-vacuum.‘Pressure cooker’ type sterilisers are designed to sterilise unwrapped, non-porous, non-fabric items such as instruments and syringes. Moist heat, when used as steam under pressure in an autoclave, kills microbes by denaturing their proteins.
37Gravity Displacement Autoclaves Steam introduced to purge out air and build pressureRaise temperature normally to 121°C at 15 pounds/square inch and maintain it for minutesFor sterilising liquids and items in wraps that steam can penetrateDecember 1, 2013In gravity (downward) displacement autoclaves, steam is introduced at the top of the chamber to purge out the cooler and denser air-steam mixture from the bottom of the chamber. The exhaust valve closes when all the air has been removed, thus allowing the pressure to build and temperature to rise.Such autoclaves are used for sterilising liquids and items in wraps that steam can penetrate. The sterilisation step itself normally lasts about 15 minutes at 121°C at kilopascal (15 pounds/square inch).
38High-Vacuum Autoclaves Air is first vacuumed out and then steam introducedFaster and better penetration throughout the loadPressure and temperature higher; 134°C at about at 30 pounds/inch2Processing time about three minutesNot suited for liquids due to need for vacuumDecember 1, 2013In high-vacuum autoclaves, the air from the steriliser chamber is first vacuumed out and then steam is introduced allowing faster and better penetration throughout the entire load. The pressure and temperature rise quickly allowing process times of three minutes at 134°C at about kilopascal (30 pounds/square inch).
39Factors Influencing Steam Sterilisation December 1, 2013Proper loading must occurAll items in load must have contact with steamItems in load must be free from grease and oilInstruments to be autoclaved must be wrapped in materials that allow steam penetration while keeping the processed item sterile during storage. Over-loading of autoclaves must be avoided to permit free access of steam throughout a load. Packages must be marked to identify their contents and date of sterilisation along with steriliser and load number to facilitate any recall and to aid in rotation of supplies.All steam sterilisers must be tested upon installation and regularly thereafter; written records of routine operation and maintenance must be kept. All staff must be thoroughly trained in autoclave operation and safety.
40Practical Tips A wide range of sterilisers is available Always sterilise items for the correct time using a clock or timerAir in the steriliser and load results in inadequate steam penetrationNever sterilise single use itemsDecember 1, 2013Always follow the manufacturer’s instructions for the type of steriliser that you are using.Air in the steriliser and load results in inadequate steam penetration and incomplete drying of the load. This is because air acts as an insulator for heat and prevents steam reaching the surface of items to be sterilised. Steam purging by opening and closing the valve, removes air and improves the steriliser's performance.Standard combinations of time and temperature for sterilisation are: 121°C for 15 minutes and 134°C for 3 minutes. You need to know the operating pressure of the autoclave and altitude of your health facility to determine correct sterilising time. If you cannot change the operating pressure then you need to extend the sterilising time.Because it is difficult to keep items sterile (items are contaminated by contact in the air), carry out sterilisation on the day of use (but not immediately before use as you need to allow time for items to cool down). Replace safety valve and gaskets (rubber seals that seal the junction of metal surfaces) immediately if they are damaged or worn.From WHO:
41Low-Temperature Mixture of steam (50-80°C) and formaldehyde vapour To process heat-resistant or heat-sensitive medical devices in specialised equipmentDevices pre-cleaned and wrapped in standard material and processed in a three-hour cycleCannot be used for liquidsFormaldehyde must be purged/ neutralised wellDecember 1, 2013In the low-temperature steam-formaldehyde (LTSF) process, steam (50-80°C) is used with vapourised formaldehyde to sterilise heat-sensitive medical devices (even those with narrow lumens). As usual, devices are cleaned and then processed.First, a vacuum is created; steam is introduced in several pulses followed by vapourisation of formaldehyde. At the end of the cycle, the formaldehyde is evacuated and completely purged out with several pulses of steam and high vacuum. Chemical and biological indicators are used to monitor the steriliser performance. It cannot be used with liquids and the potential toxicity of formaldehyde remains a concern.
42Flash Sterilisation Only to process a critical surgical item: in an emergencywhen accidentally contaminated, orwhen other means of sterilisation unavailableNever to be used for implantable items or to compensate for shortage of key instrumentsDecember 1, 2013In a Flash steriliser, steam is used to process surgical items for use when a critical item has become accidentally contaminated during an operation or when no other means of sterilisation are available. It should never be used for implantable items or to compensate for a shortage of essential instruments. Either a gravity-displacement or pre-vacuum autoclave can be used for flash sterilisation of porous or non-porous items without wrapping or with a single wrap. Waiting to read any included BIs is not possible due to the rapid turn-around needed for flash-sterilised items. Unless suitable containers are used, there is a high risk of recontamination of the processed items and also thermal injury to personnel during transportation to the point-of-use. Flash Sterilisation is not accepted in all regions.‘Flash’ sterilisation recommendationsrestrict use to emergencies, such as unexpected surgery, or dropped instruments. ‘In most emergency situations, the risk/benefit ratio is low enough that the use of flash sterilized objects is justifiable. In non-emergency situations, however, the risk/benefit ratio is higher, particularly when implantable devices are involved’‘flash’ sterilizers must never be used for implantables, suction tubing or cannulars or any other product not specifically validated for the “flash” process
43Dry Heat Sterilisation - 1 Require hot-air ovensFor glassware, metallic items, powders and oil/greaseTime two hours at 160°C and one hour at 180°CPlastics, rubber, paper and cloth cannot be placed in them due to fire riskDecember 1, 2013Hot-air ovens are used for dry-heat sterilisation. They can reach high temperatures and should be equipped with a fan for even distribution of heat. Preheating is essential before starting the sterilisation cycle. Hot-air ovens are simpler in design and safer for use than autoclaves and are suitable for sterilisation of glassware, metallic items, powders, and anhydrous materials (oil and grease). Sterilisation takes two hours at 160°C, or one hour at 180°C. Plastics, rubber, paper, and cloth must not be placed in them to avoid the risk of fires.Dry heat in an oven kills by oxidation, which is a much slower process. Dry heat is used to sterilise moisture-sensitive materials (powders) or items which steam cannot penetrate (oils and waxes).
44Dry Heat Sterilisation - 2 AdvantagesCan be used for powders, anhydrous oilsInexpensiveNo corrosive effect on instrumentsDisadvantagesHigh temperature damages some itemsPenetration of heat slow, unevenDecember 1, 2013Advantages of dry heat sterilisation include:• the ability to sterilise goods in sealed or non-porous containers• the ability to sterilise complex goods while assembled• the ability to sterilise goods which are impossible to dry in a steam steriliser or which may be damaged/corroded by the moisture of steam sterilisation• the relative mechanical simplicity of a dry heat steriliserDisadvantages of dry heat sterilisation are:• long times involved in heating, sterilising and cooling goods being sterilised• possible damage to packaging materials or to some of the items themselves arising from the high temperatures used• close monitoring and control of sterilisation conditions within packs being sterilised can be very time consuming• due to the high temperature, dry heat sterilisers provide the greatest potential for injury to personnel following contact with parts of the steriliser or the goods being processed (while they are hot), compared to the other in-facility sterilisation processes• equipment at the ‘low cost’ end of the market does not adequately maintain constant temperature conditions within the steriliser. Purchasers may not be adequately aware.
45Ethylene Oxide (EO) Colourless, flammable, explosive and toxic gas Processing cycles overnight or longerParametric release is not possibleEO and relative humidity cannot readily be measuredSpores of Bacillus atrophaeus used as biological indicators to monitor processDecember 1, 2013Ethylene oxide (EO) is used to sterilise items that are sensitive to heat, pressure, or moisture. EO is a colourless gas that is flammable, explosive, and toxic to humans. Two EO gas mixtures are available, one with hydrochlorofluorocarbons (HCFC) the other a mixture of 8.5% EO and 91.5% carbon dioxide; the latter mixture is less expensive.EO concentration, temperature, relative humidity (RH), and exposure time must all be maintained at the right levels during the process to ensure sterilisation. Gas concentration should be 450 to 1200 mg/l, temperature ranges from 37 to 63oC, RH from 40% to 80%, and exposure times from one to six hours.Parametric release is not possible since gas concentrations and RH cannot readily be measured; a BI should be included with each load. The recommended BI is Bacillus atrophaeus; loads should be quarantined until the incubation time of the BI is complete.
46Ethylene Oxide (EO) Gas Sterilisation December 1, 2013Used for heat or moisture sensitive itemsPrevents normal cellular metabolism and replication
47EO Sterilisation Advantages Items not damaged by heat or moisture Not corrosive, not damaging to delicate instruments, scopesPermeates porous materialsDissipates from materialDisadvantagesCostToxic properties of ethylene oxideAeration requiredLonger processDecember 1, 2013The main disadvantages of EO sterilisation are the long cycle times and high cost. Sterilised items must be aerated well after processing to remove all residues of EO. Risk of personnel exposure to ethylene oxide demands environmental control equipment be in place.
48Hydrogen Peroxide Gas Plasma Highly reactive/charged particles from hydrogen peroxide generated under vacuumCan be used to sterilise heat- and moisture-sensitive itemsSome plastics, electrical/electronic devices, and corrosion-susceptible metal alloysNot compatible with cellulose (linen, paper), devices with dead-end lumens, powders and liquidsSpecial wrapping requiredDecember 1, 2013Gas plasmas are generated in an enclosed chamber under deep vacuum using radio frequency or microwave energy to excite hydrogen peroxide gas molecules and produce charged particles, many of which are highly reactive free radicals. Gas-plasma can be used to sterilise heat- and moisture-sensitive items, such as some plastics, electrical/electronic devices, and corrosion-susceptible metal alloys. The spores of G. stearothermophilus are used as BIs.This is a safe process, and, as no aeration is needed, sterilised items are available for immediate use or storage. However, It is not suitable for devices with dead-end lumens, powders, or liquids. Other disadvantages include the high cost and need for special packaging material since paper or linen cannot be used. In addition, any liquid or organic residues present interfere with the process.
49Fumigation For rooms contaminated with some pathogens Such as MRSA and Clostridium difficileRelease of hydrogen peroxide, chlorine dioxide gas or possibly ozone in sealed roomsSpore strips (biological indicators) placed strategically to monitor processSpecial equipment requiredRisk of damage to sensitive itemsDecember 1, 2013Recently, there has been much interest in using fumigants to deal with healthcare-associated pathogens such as methicillin-resistant S. aureus and C. difficile in the environment. Several devices are available which vary in cost, the process used, and the degree of field testing they have undergone.A common process is to vaporise a solution of hydrogen peroxide into a sealed room, such as a patient room, for surface decontamination. No post-treatment aeration is necessary because hydrogen peroxide readily breaks down into oxygen and water. Spore strips are strategically placed throughout the room and retrieved later to monitor the effectiveness of the process. Disadvantages include incompatibility with cellulosic materials and potential corrosion of electronic devices.Chlorine dioxide generated on-site may be released as a gas for room decontamination. The rooms must not only be sealed but also darkened to prevent daylight accelerating the breakdown of the gas. Like hydrogen peroxide, chlorine dioxide naturally breaks down into innocuous by-products.Ozone can decontaminate surfaces in enclosed spaces, however it is highly unstable and potentially damaging to a variety of the materials common in health care facilities. However, an ozone-based medical device steriliser is available. It generates the gas from oxygen and at the end of the cycle converts it to oxygen and water by catalysis. The machine claims wide materials compatibility and the ability to handle narrow-lumened devices.
50Pasteurisation and Boiling Semi-critical items can be pasteurised65-77°C, 30 minExample: respiratory therapy equipmentMust be retrieved carefully for safe transport and storageDecember 1, 2013Semi-critical items, such as respiratory therapy and anaesthesia equipment, can be pasteurised by heating in water. All their parts must remain well-immersed throughout; holding the heat at about 65-77°C for 30 minutes is sufficient. Locations at higher elevations require a longer time because the boiling point of water gets lower the higher one gets from sea-level.Immersion of heat-resistant items in boiling water for about 10 minutes can substantially reduce the pathogen load, but must never be regarded as ‘sterilisation’. Pasteurisation and boiling are thus low-tech and chemical-free methods (as long as the water is pure); treated items must be retrieved carefully for safe transport and storage.
51Filtration Removal of microbes from air or heat-sensitive liquids Disinfectant-impregnated filters may inactivate trapped microorganismsExample: High-efficiency particulate air (HEPA) filtersAll filters must be checked for integrity and replaced as necessaryDecember 1, 2013A simple means of removing microbes from air or heat-sensitive liquids is by passage through membrane or cartridge filters. This process retains physical microorganisms based on their size, without killing them unless the filter matrix is impregnated with or exposed to a microbicidal agent.High efficiency particulate air (HEPA) filters are frequently used to remove microbial contamination from air in surgical theatres, microbiology laboratories, and for sterile manufacturing of pharmaceuticals. Their use in hospital wards and waiting rooms is also increasing to reduce the risk of spread of airborne pathogens. HEPA filters must be checked for integrity after installation and have a scheduled maintenance programme. Cartridge filters may be used on air-supply lines to remove microbial contamination.Membrane and cartridge filters with a nominal pore diameter of 0.2 µm are quite commonly used in the manufacture of a variety of heat-sensitive biologicals and injectables. Such filters cannot remove viruses due to their much smaller size. Cartridge filters are also common on taps for potable water and inside automatic endoscope reprocessors to protect processed devices from recontamination with bacteria in rinse water. Liquids passed through such filters are often referred to as ‘sterile’, although this is not strictly true.
52Automated Endoscope Reprocessors December 1, 2013Alternative to manual reprocessing of heat-sensitive devicesMinimise exposure of staff to pathogens and disinfectantsRequire access to reliable electric and water supplies, specific chemicals, regular maintenanceBiofilm build-up must be avoidedMedical devices are frequently manually disinfected. However, such an approach is operator-sensitive and exposes staff to infectious agents and potentially toxic chemicals. Automated endoscope reprocessors (AER) are a safer alternative, resources permitting. They require reliable supplies of electricity and water, and require expensive maintenance and consumables (disinfectants, filters, etc.). The water quality is especially important to forestall premature clogging of filters and prevent the growth of opportunistic pathogens, such as environmental mycobacteria and pseudomonads.
53Ultraviolet (UV) Light UV lamps useful for chemical-free disinfection of air and water and also possibly for decontamination of environmental surfacesBroad-spectrum microbicidal actionRequire regular cleaning and periodic replacementDecember 1, 2013Recent advances in ultraviolet (UV) lamp technology make the microbicidal potential of short-wave UV radiation viable for a variety of uses. UV lamps are increasingly popular for disinfection of water and wastewater in some regions. UV-based devices are being marketed for the disinfection of air in hospitals and clinics to reduce the spread of airborne pathogens. Devices are being marketed for the disinfection of environmental surfaces in hospitals as well in some regions.UV radiation does not add any chemicals to the water and air being treated, except for the generation of low levels of ozone. However, it cannot penetrate through dirt, and items require direct exposure to the radiation. Such lamps require regular cleaning and periodic replacement; they can still emit visible light even after the UV radiation has diminished.
54Microwaves Heating from rapid rotation of water molecules Limited use except for disinfecting soft contact lenses and urinary catheters for intermittent self-catheterisationMay be used in emergencies to treat water for drinking or to ‘disinfect’ small water-immersible plastic or glass itemsDecember 1, 2013Exposure of water-containing items to microwaves generates heat due to friction from rapid rotation of water molecules. Thus far this process has only been used for disinfecting soft contact lenses and urinary catheters for intermittent self-catheterisation. However, small volumes of water could possibly be made safe for drinking by microwaving in a glass or plastic container. Similarly, small glass or plastic objects could be immersed in water and ‘disinfected’ in a microwave oven.
55Sterilisation Process Monitoring December 1, 2013Recommended practices state that both biological and chemical indicators shall be used to monitor the sterilisation processMechanical monitoringChemical monitoringBiological monitoringFor the high vacuum process, steam penetration of the load depends on adequate air removal. This can be monitored in two ways – firstly by a ‘leak test’ - can the vacuum be maintained or will air leak in (often around the door) - and secondly by the ability of steam to penetrate a small pack of towels used in the ‘Bowie Dick’ test. If these tests are satisfactory then an alternative monitoring approach is ‘parametric release’. This system relies on ensuring that the autoclave cycle has fulfilled all specifications with regard to temperature, pressure and time using calibrated instruments in addition to, or in place of, BIs. Since this approach is based on measurable data and calibrated equipment, the results tend to be more reliable and much more rapid than the use of BIs.Parametric release – the release of sterile items based on the compliance with defined critical parameters of sterilisation without having to perform sterility tests (biological monitoring).Traditionally, Biological Indicators (BI’s) are used as an integral part of the release process for sterilised products. Parametric release can be used if the data demonstrating correct processing of a batch provides sufficient assurance, on its own, that the process designed and validated to ensure the sterility of the product has been delivered. Sterilisation methods using steam, dry heat and ionising radiation may be considered for parametric release.
56Chemical Indicators External Chemical Indicator process indicator - autoclave tapedistinguishes processed from unprocessed medical devicessecures packlabels packCheck external indicator to ensure it has changed color before using any packageIf the indicator did not change, do not useDecember 1, 2013Chemical indicators (CI) are used to assess if the required time and temperature were attained during the sterilisation process. One type of CI is an autoclave tape that can be affixed to the outside of a package; it shows a colour change if the package was exposed to heat. Though CIs are not meant to indicate that a product has been sterilised, they can help to detect equipment malfunctions and identify procedural errors.Indicator strips, such as TST (TimeSteamTemperature), should be used – ideally during every sterilisation cycle or at least once a week – to make sure sterilisation has been satisfactorily carried out.Class 5 chemical indicator: Is an integrating indicator. This chemical indicator reacts to all three parameters of sterilisation which include proper amount of time, temperature and pressure of the sterilizer. They have been correlated to the performance of a biological indicator when used according to the manufacturers conditions noted on the label.
57Biological Indicators Requires routine monitoring dailyTest must be dated and labeledOnce removed from the steriliser the test pack opened, BI labeled, crushed and incubated in the incubatorRecords of time, date of incubation and staff initials is required and then time and date and initials of the staff reading the final BI resultDecember 1, 2013Biological indicators (BI) contain the spores of the bacterium Geobacillus stearothermophilus. Commercially-available spore strips or vials containing the spores are strategically placed in the load to be sterilised. After a cycle, the BI are cultured or evaluated for growth and they must all indicate no growth to declare the sterilisation process a success.In Europe- not daily – every 400 charges or every 6 months. Validation of sterilsers used instead.
58Biological Monitoring December 1, 2013Steam Geobacillus stearothermophilusDry heat B.atrophaeus (formerly B.subtilis)EO B.atrophaeusNew low temperature sterilisation technologiesPlasma sterilisation (Sterrad) B.atrophaeusPeracetic acid - Geobacillus stearothermophilusDifferent microorganisms are used for the different methods of sterilisation.
59Main IP&C prioritiesDevelopment of reprocessing protocols for instruments and equipment based on generally recognised standards and manufacturer's recommendationsUse of clean water for cleaning items thoroughlyMaintenance, use, and monitoring of equipment, e.g., autoclavesDiscarding items that cannot be cleaned or reprocessed adequatelyStoring reprocessed items away from potential sources of contaminationDecember 1, 2013
60References - 1Guidelines for Environmental Infection Control in Health-Care Facilities. MMWR 2003; 52(RR10):1-42.Ontario Ministry of Health & Long-Term Care. Provincial Infectious Diseases Advisory Committee (PIDAC) Best Practices for Cleaning, Disinfection and Sterilization in All Health Care Settings,December 1, 2013
61References - 2Rutala WA, Weber DJ. Guideline for Disinfection and Sterilization in Healthcare Facilities, Centers for Disease Control and Prevention, Atlanta, GA.Snyder, OP. Calibrating thermometers in boiling water: Boiling Point / Atmospheric Pressure / Altitude Tables.Sattar A. Allen Denver Russell Memorial Lecture, The use of microbicides in infection control: a critical look at safety, testing and applications. J Appl Microbiol 2006; 101:December 1, 2013
62Quiz Disinfection: The most reliable means of sterilisation is: Decontamination results in an item that is safe for patient reuse. True/False.Disinfection:Is used for items that will contact intact skinInvolves chemical agentsReduces the numbers of microorganismsAll of the aboveThe most reliable means of sterilisation is:Ethylene oxideSteamDry heatPlasmaDecember 1, 2013FalseD3. B
63International Federation of Infection Control IFIC’s mission is to facilitate international networking in order to improve the prevention and control of healthcare associated infections worldwide. It is an umbrella organisation of societies and associations of healthcare professionals in infection control and related fields across the globe .The goal of IFIC is to minimise the risk of infection within healthcare settings through development of a network of infection control organisations for communication, consensus building, education and sharing expertise.For more information go toDecember 1, 2013