Sterilization and Disinfection Policy for Hospital

Sterilization and Disinfection Policy

DEFINITIONS

Cleaning
This is physical removal of organic material or soil from an object. It is usually achieved by applying water with or without a detergent.

Disinfection
A procedure that achieves killing of vegetative organisms and reduction of microbial load to safe levels, spores Will not usually be destroyed.

Disinfectant
A chemical agent used for disinfection.

Antiseptics
These are types of non-toxic disinfectants that may be applied to the skin and other living tissues. An antiseptic should not be used to disinfect instrument or the environment.

Sterilization
A procedure that achieves completes killing or removal of all types of microorganisms, including resistant spores.

Chemical Sterilants
These are a small range of chemical compounds, which under controlled conditions can kill all living organisms including spores, e.g. glutaraldehyde, ethylene oxide.

Note : Cleaning with detergent and water removes above 80% while chemical
disinfectants remove up to 99% of microorganisms.

Methods of Sterilization

Sterilization can be achieved by any of the following methods.

1. Steam under Pressure [Autoclaves] : This is applied at high temperature [134oC for 3 minutes] or low temperature [121oC for 15 minutes]

2. Dry heat [hot air sterilizes] : This is applied at 160oC with holding time 60 minutes. The total cycle time takes 2-2 ½ hours.

3. Chemical methods, (use of sterilant) : This is applicable for heat sensitive materials at a temperature of 55°C [30-55°C]. The following chemical sterilants are used.
a. Ethylene oxide gas : chamber pressure is usually maintained at 5 - 10 psig. Exposure time varies from 3 hours to 16-36 hours depending on temperature [longer at lower temperature].
b. Glutaraldehyde 2% solution : This preparation sterilizes reliably in 10 hours, but 3 hours should provide adequate sporicidal effects. Treatment for 20 minutes will only disinfect.
c. Low temperature steam and formaldehyde : This utilizes steam at sub-atmospheric pressure. Usual temperature 71 — 75°C 1-3 hours is required for sterilization’s. Sporicidal activity with low temperature steam is less than for steam at high temperature, but the process is reasonably efficient if conditions are strictly controlled.

4. Filtration : It uses suitable bacteria proof filter to remove the organisms. It is aqueous solutions particularly suitable for thermolabile ingredient infiltration of air removes dust particles and bacteria.

5. Radiation : The following methods of radiation are used for sterilization :
a. Ultraviolet radiation : It has a poor penetrating power and is absorbed extensively by glass, plastics and turbid liquids. It is suitable only for sterilizing air and water in thin layer, and hard impermeable substances.
b. Gamma radiation : It is highly penetrative and does not leave residual radioactivity on object being sterilized. It produces negligible temperature rise in the irradiated object at normal dosage. It is used for sterilizing some thermolabile pharmaceuticals and surgical products.

Methods of Disinfection

1. Cleaning alone.
2. Exposure to steam of boiling water at atmospheric pressure above 100°C For 5 — 10 minutes.
3. Pasteurization at 75°C for at least 10 minutes.

Factors determining the effectiveness of chemical disinfection :

1. Is the correct type of chemical agent being selected for the purpose required?
2. Has a suitable concentration of the chemical agent been used?
3. It the time of exposure to disinfectant sufficient and had adequate prior cleaning been carried out?
4. Has the correct pH been used?
5. Are in activating materials present?
6. What is the temperature and volume of the disinfectant in use?
7. Are the containers for the only disinfectant cleaned adequately?

1. Disinfection policy
It is necessary that all members of staff know the correct and approved agents for disinfection in the Hospital. This is important for the prevention of infection in the hospital environment. The effective use of antiseptics, disinfectants and sterilization procedures constitutes and important factor in preventing nosocomial infections.
a. Disinfectants must be used at the recommended concentrations neither to neither strong nor too weak.
b. The correct disinfectants must be used for the particular purpose for the recommended exposure time.
c. Disinfectants must be used within the expiry date and be freshly prepared.
d. For the disinfectants that are dispersed undiluted there should be :

• Complete instructions for accurate dilution and use.
• Labels must include the name of preparation, in use concentration, expiry date of unopened product, storage requirements, date of issue and date after which the solution should not be used.
• Containers with no labels that are broken or leaking must be returned to the stores.

1.1 Where sterility is not required, disinfecting is sufficient.
1.2 Chemical disinfectants should be used only where :
a. Sterility is not essential
b. Cleaning is not sufficient
c. Disinfection by heat is not possible
d. Disposable equipment cannot be economically used.
1.3 Use dilutions of disinfectants should be freshly prepared. Any remaining disinfectant should be discarded and the container washed thoroughly before refilling. Containers should have glass or plastic closures (not cork) which can be cleaned.
1.4 It is mandatory to display the expiry date on disinfectant containers.
1.5 Instruments should not be stored in disinfectant solutions.
1.6 Disinfectant solutions must not be mixed or detergents added unless they are compatible.
1.7 Manufactures instructions must be consulted on compatibility of materials with the method of sterilization or disinfection.
1.8 Disinfectants that are reconstituted at ward level must be dated and discarded after 24 hours.
1.9 Disinfectants must never be topped up.
1.10 Each Supervisor must ensure that decontamination of all items / equipment in their departments, are carried in accordance with the guidelines provided in this policy.
1.11 New items of equipment that are not included in this policy should have a written protocol that complies both with the manufacture’s recommendations or disinfection and Infection Control requirement.

NOTE : It has been observed that cleaners of the House Keeping Unit of the hospitals do not have any idea on the above factors and they should be trained and educated on this aspect of Chemical Disinfection cleaning process of floors, walls etc.

2. Disinfection principles
2.1 Choice of method :
The choice of method of disinfection or sterilization depends on a number of factors that include.
a. Risk of patients and health care workers from equipments
b. Microorganisms involved.
c. Type of material to be disinfected.
d. Level of Contamination required for the procedure.

2.2 Risk
The risk of patients from equipment may be classified into four
categories :
a. High risk : This includes item in close contact with a break in the skin, mucous membrane of introduced into a sterile body area. Items in this category should be sterilized by heat if possible or if heat liable may be treated with low temperature steam and formaldehyde or liquid chemical disinfectant [Cidex]. Aim is sterilization.
b. Intermediate risk : this includes items in close contact with mucous membranes, body fluids or contaminated with particularly virulent or readily transmissible micro-organism or if the items are to be used on a highly susceptible patients or sites. Aim is sterilization.
c. Low risk : This includes items in contact with normal and intact skin, e.g. stethoscopes, crockery and cutlery. Aim is cleaning with detergent and water.
d. Minimal risk : Items in close contact with the patient or his/her immediate surroundings e.g. bed frames, lockers, walls, and ceilings. Aim is cleaning with detergent and water.

2.3 Cleaning and Drying
Cleaning is a process which removes soil e.g. dust, dirt, and organic matter along with a large portion of micro organisms a further reduction will occur in drying as microorganisms cannot multiply on clean dry surfaces. Thorough cleaning with detergent and water is adequate for most surfaces in the hospital environment. Cleaning is a prerequisite of disinfection or sterilization.

2.4 Disinfection
Disinfection is the destruction of pathogenic micro organisms but not usually bacterial spores. The process does not kill all micro - organisms but reduces them to a level, which is not harmful to health. Chemical disinfection should only be used if heat treatment is impractical or may cause damage to the equipment.

3. Recommended uses of chemical disinfection
The disinfectants commonly used are : Phenolics, Glutaraldehyde, Hypochlorites.
3.1 Antiseptics : An antiseptic is a non-toxic disinfectant, which can be applied to the skin or living tissues. An antiseptic should not be used to disinfect instrument or the environment. Antiseptics include : Savlon, Betadine, Microshield Rub.

3.2 Sterilization : Sterilization is the process, which achieves the complete destruction or removal of all micro — organisms including bacterial spores. Equipment and materials used in procedures involving a break in the skin or mucous membranes must be sterilized.
Sterilization include the following methods :
a. Steam under pressure [autoclaving] at e.g 132°C
b. Dry heat in the oven at 160 degree C
c. Exposure to Ethylene oxide gas. (EO)
d. Plasma sterilization.
e. Immersion in glutaraldehyde for a prolonged period.

4. Chemical disinfectants - agents
Cleaning with detergent and water removes about 80% while chemical disinfectants remove up 99% of micro — organisms.
4.1 individual agents
The Most Common Used disinfectants in the Hospital are :

4.1.1 Clear Soluble Phenolics
a. Characteristics : This group can be used at a dilution of 1% for routine cleaning and at 2% for dirty and contaminated materials and 5% for laboratory purposes. They have a wide range of bactericidal and fungicidal activities including tuberculosis activity but poor action against spores and virus. They are usually combined with detergent to aid the cleaving process.

• Organic matter does not readily inactivate them.
• Rubber and plastics absorb them.

b. Use : Phenolics are used for environmental disinfection. They are the agents of choice for Mycobacterium tuberculosis and MRSA and other multiple resistant bacteria. They are used in a theater after a “dirty case”.
c. Precautions

• Respiratory irritation may occur if used at concentrations above those listed in this policy.
• Appropriate protective clothing must be worn when handling phenolic disinfectants - they can be absorbed through the skin, therefore skin must be protected during use. Latex/Rubber gloves must be worn.
• Phenolic solution must not be used on equipment that comes into contact with skin or mucous membranes.
• Phenolic solution may taint food. Therefore it must not be used on food preparation surface or Equipment.

4.2 Halogens
These are chlorine-based disinfectants that include :

• Sodium hypochlorite / Dichlorisocyanurates.
• Hypochlorite / Hypobromite

a. Characteristics

1. The activity of the compound is due to chlorine.
2. They are bactericidal against bacteria, some fungal protozoa, algae & viruses and are specially recommended if there is hazard of infection.
3. They act rapidly by the release of available chlorine.
4. Solutions are unstable after dilution and therefore must be stored according to Pharmaceutical recommendations and used before the expiry date. They must be freshly prepared daily — light heat and heavy metal accelerates decomposition.
5. Chlorinated disinfections are corrosive to metals, damage plastic, rubber and similar components on prolonged contact or if used at the incorrect dilution.
6. Chlorinated disinfectants bleach fabrics, carpets and soft furnishings
7. Activity is pH—dependent : organic matter inactivates them.

b. Use

1. It is the disinfectant of choice for dealing with viral infections. e.g. Hepatitis B.C. HIV for environmental disinfection of blood spillage, body fluid spillage.
2. It is used for laboratory discard jars.
3. It is non-abrasive cleaning agents which may be used for environmental disinfection of hard surfaces i.e baths, sinks.
4. It is used to disinfect baby bottles / teats / spoons/ catering surfaces/equipment.

c. Precautions

1. Chlorinated disinfectants can cause irritation of the skin, eyes and lungs if used frequently in a poorly ventilated area.
2. Appropriate protective clothing must to worn when handling
3. Hypochlorites, Latex gloves disposable plastic aprons.
4. Do not mix strong acids or acidic body fluids [urine] with chlorine based disinfectants as chlorine gas will be released. Urine spillage should be cleaned first them disinfected with hypochlorite.
5. Do not submerge animal fibers [e.g wool or silk] due to strong proteolytic action.
6. Prolonged contact with stainless item should be avoided otherwise corrosion will result.

4.3 Glutaraldehyde [ Cidex 2% ]
a. Characteristics

1. It is an alkaline solution. It requires activation with 2% Buffered solution, once activated remains active for 14 days depending on the brand or preparation used and the frequency of use. It is less irritant than Formaldehyde.
2. Glutaraldehyde has a wide range of activity. It is bactericidal, sporicidal, virucidal, [Hepatitis B, C and HIV]. Prolonged immersion in Glutaraldehyde [60 minutes] is required to kill Mycobacterium tuberculosis and related organisms.
3. It has little inactivation effect by organic matter.
4. To ensure sporicidal activity exposure period of at least 3 hours is required. Up to 10 hours may be necessary in some cases.
5. It is non — corrosive to metals and other materials.

b. Use
It is used to disinfect heat sensitive items i.e. Endoscopes.
c. Precautions

1. Glutaraldehyde is an eye and nasal irritant and may cause respiratory illness [asthma] and allergic dermatitis.
2. 2. It should be used in a well-ventilated place.
3. Eye protection, plastic apron and gloves must be worn when Glutaraldehyde liquid is made up, disposed of or when immersing instruments.
4. Aldehydes should be stored away from heat source and in containers with close fitting lids.

4.4 Formaldehyde [Formalin]
a. Characteristics

1. It is active against vegetative bacteria fungi and many viruses. It is very slowly effective against spores and acid — fast bacteria [e.g. Mycobacterium tuberculosis].
2. It is irritant and activity is reduced in the presence of organic matter. It does not penetrate organic matter well.
3. It is used for preservation of tissue specimens.
4. Aldehydes should be stored away from heat sources and in containers with close fitting lids.

b. Uses
Formaldehyde is used mainly as a gaseous fumigant to disinfect safety cabinets in the laboratory and to fumigate rooms of patients with a highly dangerous and transmissible infectious disease who are kept in strict isolation.

UPDATE

Though still practiced in many Hospitals, “Fumigation” is now an outdated practice and should not be used to sterilize rooms etc. Scrubbing with disinfectant has replaced fumigation world wide.
c. Precautions
Formaldehyde is a potent eye and nasal irritant and may cause respiratory distress and allergic dermatitis. Gloves, goggles and aprons should be worn when preparing and disposing of formaldehyde solutions.

4.5 Alcohols [70% ethyl alcohol, 60-70% Isopropyl alcohol]
a. Characteristics

1. This agent does not penetrate well into organic matter especially protein based and should only be used on physically clean surfaces.
2. It is rapidly bactericidal & fungicidal and it is used for disinfection of smooth surfaces e.g. trolley tops, incubators, and skin [needle puncture site].

b. Use

1. It is used for its rapid action i.e. alcohol impregnated wipes to disinfect the skin prior to injection.
2. May be used for hand disinfection after the addition of 0.1 - 1.0% glycerin [should be applied to physically clean hands].
3. It can be used with other bactericidal agents such as chlorhexidine and Povidone iodine for pre-operative skin disinfection prior to invasive procedures. It can also be used to disinfect some instruments in laboratory work e.g. probes.

c. Precautions

1. It must be stores in a cool place.
2. Alcohol mixtures are flammable. Do not allow coming in contact with hot surfaces, flames, electrical equipment or other sources of ignition.
3. Do not leave bottles uncapped as alcohol vapours irritate mucous membranes especially in an enclosed space and evaporates also.

4.6 Biguanides [Chlorhexidine]
Characteristics
Soap and organic matter inactivate these agents. They are highly active against gram - positive organisms but less so against gram — negative bacilli, esp Ps. Aeruginosa and Proteus spp.

4.7 Iodine and Iodophors [Povidone iodine/Betadine iodine]
a. Characteristics

1. This group has a wide range of bactericidal, virucidal, fungicidal and some Sporicidal activities and also active against some viruses and fungi.
2. They are inactivated by organic material and may corrode metal.
3. They have very rapid action.
4. 1% w/v solution in 70% alcohol is an effective skin antiseptic, but might cause skin reaction.

b. Use
It is used exclusively as an antiseptic for skin and mucous membranes. It is available as :

1. Iodine : Aqueous iodine and Tincture of iodine.
2. Povidone iodine 10% — for skin disinfection [Microshield]. This is less irritant that iodine and does not stain the skin.
3. Povidone iodine 7.5% — Microshield scrub for hand/ skin disinfection.
4. Povidone iodine 10% with 70% Spirit Microshield alcoholic solution] for pre—operative skin preparation and skin disinfection prior 10 invasive procedures.

c. Precautions
Tincture and iodine and aqueous iodine solutions can cause skin irritation, while iodophors [Betadine] do not stain and have in most cases non—irritant skin activity.

Potassium Permanganate

a. Characteristics
It has a limited topical efficacy against bacteria and fungi.
b. Use
1:5000 concentrations have effective bactericidal actions, but is irritant to tissues. So 1:10,000 concentration is usually used.