Disinfection Policies in
Mansoura University
Hospitals
By
Prof. Mohammed A. Abou El-ela
Professor of Microbiology & Immunology
MEDICU Director
Introduction
- All hospitals and health care facilities
should have a decontamination policy,
and should help staff to decide what
decontamination process should be
used for each item of medical
Equipment
- And this what we are following and
implementing in Mansoura University
Hospitals
Efficacy of Disinfection / Sterilization
Influencing Factors
• Cleaning of the object.
• Organic and inorganic load present.
• Type and level of microbial contamination.
• Concentration of and exposure time to
disinfectant / sterilant.
• Nature of the object.
•Temperature and relative humidity.
Decontamination
Decontamination is the process by which
microorganisms are removed, inactivated or
destroyed; in order to render an object safe i.e.
an object is no longer capable of transmitting
infectious particles when used, stored or disposed.
It includes:
- Cleaning.
- Disinfection.
- Sterilization.
Decontamination Steps
1- Cleaning.
2- Disinfection.
3- Sterilization.
4- store or using
Cleaning
- Cleaning is the removal of all foreign material (dirt, organic
matter and microorganisms) from an object.
-Two key components of cleaning are friction to remove foreign
matter and fluids to remove or rinse away contamination.
- Cleaning is the first & the most essential step in reprocessing of instruments and equipment. - If instruments and other items have not been cleaned,sterilization and disinfection may not be effective.- Cleaning may be manual or mechanical cleaning includes ultrasonic cleaners or washer / disinfectors .-
Disinfection
Disinfection is a process that reduces the number of pathogenic
microorganisms, but not necessarily bacterial spores, from
inanimate objects, to a level which is not harmful to health.
The broad category of disinfection may be subdivided, according to the
anti-microbial activity of the disinfectant, into:
- High-level disinfectant (HLD)
- Intermediate-level disinfectant (ILD
- Low level disinfectant (LLD)
• High-level disinfectant (HLD): is capable of killing
some bacterial spores; when used in sufficient
concentration and temperature. It is effective against all
vegetative bacteria, fungi and all viruses.
•Intermediate-level disinfectant (ILD): destroys all
vegetative bacteria, including Mycobacterium tuberculosis,
lipid enveloped and some non-lipid enveloped viruses,
and fungus spores, but not bacterial spores.
•Low-level disinfectant (LLD): destroys all vegetative
bacteria (except Mycobacterium tuberculosis), lipid
viruses, some non-enveloped viruses and some fungi, but
not bacterial spores.
Decreasing order of resistance of microorganisms
to disinfection and sterilization.
1. Prions
2.
3.
4.
5.
6.
7.
8.
Bacterial spores
Coccidia
Mycobacterium tuberculosis
Non lipid or small viruses
Fungi
Vegetative bacteria
Lipid viruses
Spaulding classification
Spaulding for reprocessing of contaminated
medical devices. The system classifies devices as
1. Critical,
2. Semi-critical, or
3. Non-critical items;
Based on the risk of infection of patient from
contaminated devices.
High-risk “Critical” Items
Classification: Critical objects enter normally
sterile tissue or vascular system, or through
body cavities.
Object: Sterility.
Level germicidal action: Kill all microorganisms,
including bacterial spores.
Examples: Surgical instruments and devices;
cardiac catheters; implants; etc.
Method: Steam, EO gas, hydrogen peroxide
plasma or chemical sterilization .
Intermediate-risk “Semi-critical”
Items
Classification: Semicritical objects come in
contact with mucous membranes or skin
that is not intact.
Object: Free of all microorganisms except
some bacterial spores.
Level germicidal action: Kills all
microorganisms except some bacterial
spores.
Examples: Respiratory and anesthesia
equipment, flexible endoscopes,
thermometer, etc.
Method: High-level disinfection
Low-risk “Non-critical”
Items
Classification: Noncritical objects come in contact
with normal intact skin, but not with mucous
membranes.
Object: Kill all micro-organisms. Level germicidal
action: Kill vegetative bacteria, fungi and lipid
viruses.
Examples: Stethoscopes, a blood pressure cuff
and inanimate environment (e.g. walls, floors,
ceilings, furniture, sinks, etc.).
Method: Low-level disinfection
Thermal or chemical processes.
•Thermal
•Preferred whenever possible:
• It is generally more reliable.
• Leaves no residues.
• Is more easily controlled
• Non-toxic.
•Heat sensitive items have to be reprocessed with a
chemical disinfectant. High Level Disinfection (HLD) - Semicritical items:
• Chemical HLD
•
•
Commonly used for heat-labile equipment (e.g.
endoscopes) where single use is not cost effective.
A limited number of disinfectants can be used for this
purpose, e.g.:
• Glutaraldehyde 2% for 20 min.
• Hydrogen peroxide 6-7.5% for 20-30 min.
• Peracetic acid 0.2-0.35 % for 5 min.
• Ortho phthalaldehyde (OPA) for 5 -12 min.
Sterilization
Disadvantages of steam
sterilization:
• Items must be heat and
moisture resistant (not
deteriorated).
• Will not sterilize powders,
ointments or oils.
• Needs good maintenance.
Dry-Sterilization heat
(Hot air oven)
• Dry heat is preferred for
reusable glass, metal
instruments, oil, ointments and
powders
• Do not use this method of
sterilization for other items,
which may melt or burn.
Advantages of dry-heat
sterilization
• Can be used for powders,
anhydrous oils, and glass.
• Reaches surfaces of instruments
that cannot be disassembled.
• No corrosive or rusting on
instruments effect instruments.
• Low cost.
Disadvantages of dry-heat
sterilization
• Penetrates materials slowly and
unevenly.
• Long exposure time’s necessary.
• High temperatures damage rubber
goods and some fabrics fabrics.
• Limited package materials.