Cleaning,
Disinfection,
and Sterilisation
1. Differentiate between disinfection and
sterilisation.
2. Explain different types of sterilisation.
3. Outline the process for cleaning patient
care items.
December 1, 2013
Learning Objectives
2
• 90 minutes
December 1, 2013
Time involved
3
• Cleaning, disinfection, and sterilisation are the
backbone of infection prevention and control
• Proper cleaning essential before any disinfection
or sterilisation process
• Failure to sterilise or disinfect reusable medical
devices properly may spread infections
• The type and level of device decontamination
depends upon the nature of the item and its
intended use
December 1, 2013
Key points - 1
4
• Steam sterilisation effective only when preceded
by
• Thorough pre-cleaning, proper packaging/loading, and
careful monitoring of autoclaves
• Chemical disinfectants must be selected, used,
and discarded to minimise harm
• Those responsible for processing contaminated
items must be fully trained and wear protective
clothing when necessary
• Clearly written policies and procedures must be
available on-site for training personnel and for
monitoring their performance
December 1, 2013
Key points - 2
5
• A process of treatment that renders a
medical device, instrument, or
environmental surface safe to handle
• Does not necessarily mean that the item is
safe for patient reuse
December 1, 2013
Decontamination
6
Everyone responsible for handling and
reprocessing contaminated items must:
• Receive adequate training and periodic retraining
• Wear appropriate personal protective equipment
(PPE)
• Receive adequate prophylactic vaccinations
December 1, 2013
Pre-Cleaning/Cleaning
7
Divided hospital instruments into general
categories based on the risk of infection involved
in their use
•
•
•
December 1, 2013
Spaulding Classification
Critical items
Semi critical item
Non critical items
8
• Enter normally sterile tissues, the vascular
system, or equipment through which blood
flows
• Items must be properly and safely pre-cleaned
and sterilised before use
December 1, 2013
Critical Items
9
• Implants
• Prosthetic devices
• Surgical instruments
• Needles
• Cardiac catheters
• Urinary catheters
• Biopsy forceps of endoscope
December 1, 2013
Critical Items - Examples
10
• Contact mucous
membranes but do not
penetrate soft tissue or
body surfaces
• Meticulous physical
cleaning followed by
appropriate high-level
disinfection
December 1, 2013
Semi-critical Items
11
• Flexible fiberoptic endoscopes
• Respiratory therapy equipment
• Anaesthesia equipment
• Endotracheal tubes
• Bronchoscopes
• Vaginal specula
• Cystoscope
• Hand-piece
December 1, 2013
Semi-critical Item - Examples
12
• Direct contact with the patients intact skin
(unbroken skin)
• Little risk of pathogen transmission directly to
patient
• Clean and disinfect using a low to
intermediate level disinfectant
December 1, 2013
Non Critical Items
13
Items which are in contact with intact skin
•
•
•
•
•
•
Bedpans
Blood pressure cuffs
Crutches
Stethoscopes
Face mask
X-ray machine
December 1, 2013
Examples of Non Critical Items
14
A process that eliminates many or all
pathogenic microorganisms on
inanimate objects, with the exception of
bacterial spores
December 1, 2013
Disinfection
15
• The complete elimination or destruction of all
forms of microbial life
• Includes large numbers of highly resistant
bacterial spores
December 1, 2013
Sterilisation - 1
16
• Store in clean, dry place
• Protect wrapping
• Inspect before use
December 1, 2013
Sterilisation - 2
17
• Written and up-to-date policies and procedures
must be available on-site for training/monitoring
staff responsible for device reprocessing
• Train staff fully and retrain as necessary;
maintain written records
• The staff must also be provided with:
December 1, 2013
Staff Training and Protection
• Personal protective equipment (PPE)
• Prophylactic vaccinations
18
• Single-use items must be safely discarded after
use
• e.g., injection needles
• No 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, 2013
Single-Use Items
19
• Method to be used will depend on:
• Device’s intended use
• Risk of infection
• Degree of soilage
December 1, 2013
Choice of Method
• Process must not damage the device
20
• Reduction in numbers of pathogens on
inanimate surfaces/objects
• For items that will contact intact skin or mucous
membrane
• Use physical or chemical agents or both
December 1, 2013
Disinfection
• Level of disinfection
• High-level
• Intermediate-level
• Low-level
21
• Active against vegetative bacteria, viruses
(including the non-enveloped ones), fungi, and
mycobacteria
• May have some activity against bacterial spores
December 1, 2013
High-level Disinfectants - 1
• With extended contact times
• HLDs are used to disinfect heat-sensitive and
semi-critical devices
• Such as flexible fibreoptic endoscopes
22
• HLDs typically require 10-45 minutes contact
time
• Depends on the temperature
December 1, 2013
High-level disinfectants - 2
• After disinfection, items require thorough
rinsing/flushing with sterile or filtered water to
remove any chemical residues
•
They must then be dried with an alcohol rinse or by
blowing clean, filtered air through the device’s
channels prior to storage
23
• Active against vegetative bacteria,
mycobacteria, fungi and most viruses
• May fail to kill spores, even after prolonged
exposure
December 1, 2013
Intermediate-level Disinfectants
24
• 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
December 1, 2013
Low-level Disinfectants
25
Agents
Alcohols (60-90%)
including
ethanol and
isopropanol
Spectrum
Uses
Low- to intermediatelevel disinfectant.
Used for
decontaminating the
outside of some semicritical 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.
Advantages
Fast acting.
No residue.
Non-staining.
Low cost. Widely
available in many
countries for
medicinal and
research purposes.
Disadvantages
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, 2013
Chemical disinfectants in
health care
26
Agents
Chlorine and chlorine
compounds: the most
widely used is an
aqueous solution of
sodium hypochlorite
5.25-6.15% (domestic
bleach) at a
concentration of 1005000 ppm free
chlorine
Spectrum
Low- to high-level
disinfectant.
Uses
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.
Advantages
Low cost, fast acting.
Readily available in
most settings.
Available as liquid,
tablets or powders.
Disadvantages
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, 2013
Chemical disinfectants in
health care
27
Agents
Aldehydes
Glutaraldehyde: ≥2%
alkaline or acidic
solutions. Also
formulated with
phenol-sodiumphenate and
alcohol.
Spectrum
High-level
disinfectant.
Uses
Widely used as highlevel disinfectant for
heat-sensitive semicritical items such as
endoscopes.
Advantages
Good material
compatibility.
Disadvantages
Allergenic and
irritating to skin and
respiratory tract.
Must be monitored
for continuing efficacy
levels when reused.
December 1, 2013
Chemical disinfectants in
health care
28
Agents
Orthophthalaldehyde
(OPA) 0.55%
Spectrum
High-level
disinfectant.
Uses
Advantages
High-level disinfectant Excellent stability over
for endoscopes.
wide pH range.
Superior
mycobactericidal
activity compared to
glutaraldehyde. Does
not require activation.
Disadvantages
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, 2013
Chemical disinfectants in
health care
29
Agents
Peracetic acid 0.20.35% and other
stabilised organic
acids.
Spectrum
Uses
Advantages
Disadvantages
High-level
disinfectant/sterilant.
Used in automated
endoscope
reprocessors. Can be
used for cold
sterilisation of heatsensitive 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.
Environmentallyfriendly by-products
(oxygen, water, acetic
acid).
Corrosive to some
metals.
Unstable when
activated. May be
irritating to skin,
conjunctivae and
mucous membranes.
December 1, 2013
Chemical disinfectants in
health care
30
Agents
Spectrum
Hydrogen peroxide
7.5%.
High-level
disinfectant/sterilant.
Hydrogen peroxide
7.5% and peracetic
acid 0.23%
High-level
disinfectant/sterilant.
Uses
Can be used for cold
sterilisation of heatsensitive critical
items. Requires 30
minutes at 20oC.
For disinfecting
haemodialysers.
Advantages
No activation. No
odour.
Environmentallyfriendly by-products
(oxygen, water).
Fast-acting (high-level
disinfection in 15
min.). No activation
required. No odour.
Disadvantages
Not compatible with
brass, copper, zinc,
nickel/silver plating.
December 1, 2013
Chemical disinfectants in
health care
Not compatible with
brass, copper, zinc,
and lead. Potential for
eye and skin damage.
31
Agents
Phenolics
Spectrum
Uses
Low- to intermediatelevel disinfectant.
Has been used for
decontaminating
environmental
surfaces and noncritical items.
Concerns with toxicity
and narrow spectrum
of microbicidal
activity.
Advantages
Not inactivated by
organic matter.
Disadvantages
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, 2013
Chemical disinfectants in
health care
32
Agents
Iodophores (30-50
ppm free iodine)
Quaternary
ammonium
compounds
Spectrum
Uses
Low-level disinfectant. Used on some noncritical items, e.g.,
hydrotherapy tanks;
however, main use is
as an antiseptic.
Low-level disinfectant Used mainly on
unless combined with environmental
other agents.
surfaces. Can be used
on skin.
Advantages
Relatively free of
toxicity or irritancy.
Stable with good
detergent properties
(cationic detergent).
Usually non-irritating.
Disadvantages
Inactivated by organic
matter. Adversely
affects silicone tubing.
May stain some
fabrics.
Relatively narrow
microbicidal
spectrum, but range
of activity can be
expanded when
combined with other
agents, e.g., alcohols.
December 1, 2013
Chemical disinfectants in
health care
33
• Develop a policy for chemical disinfection
• Disinfectants may be supplied ready to use or
may need to be diluted
• Label bottles or containers with the name and
concentration of disinfectant and, for diluted
disinfectants, the date of dilution/preparation
• Prepare dilutions with clean water
• Prepare small amounts at a time to avoid
wastage
December 1, 2013
Practical Tips - 1
34
• Do not mix freshly made diluted solution with
old solution
• Wash and dry the container before filling with
new solution
• Clean, rinse and dry items thoroughly before
disinfecting
• After disinfection, rinse thoroughly with clean
water to remove all chemical residues
• Alcohol solutions can be allowed to dry without
rinsing
December 1, 2013
Practical Tips - 2
35
• Requires direct contact of an item with steam at
a required temperature and pressure for a
specified time
• Most reliable
• Non-toxic
• Has broad-spectrum microbiocidal activity
• Good penetrating ability
• Cheap and easy to monitor for efficacy
• 2 main types: gravity and pre-vacuum
December 1, 2013
Steam Sterilisation
36
• Steam introduced to purge out
air and build pressure
• Raise temperature normally to
121°C at 15 pounds/square inch
and maintain it for 15-45
minutes
• For sterilising liquids and items
in wraps that steam can
penetrate
December 1, 2013
Gravity Displacement Autoclaves
37
• Air is first vacuumed out and then
steam introduced
• Faster and better penetration
throughout the load
• Pressure and temperature higher;
134°C at about at 30 pounds/inch2
• Processing time about three minutes
• Not suited for liquids due to need for
vacuum
December 1, 2013
High-Vacuum Autoclaves
38
• Proper loading must occur
• All items in load must have contact with
steam
• Items in load must be free from grease
and oil
December 1, 2013
Factors Influencing Steam
Sterilisation
39
• A wide range of sterilisers is available
• Always sterilise items for the correct time
using a clock or timer
• Air in the steriliser and load results in
inadequate steam penetration
• Never sterilise single use items
December 1, 2013
Practical Tips
40
• Mixture of steam (50-80°C) and
formaldehyde vapour
• To process heat-resistant or heatsensitive medical devices in specialised
equipment
• Devices pre-cleaned and wrapped in
standard material and processed in a
three-hour cycle
• Cannot be used for liquids
• Formaldehyde must be purged/
neutralised well
December 1, 2013
Low-Temperature
41
• Only to process a critical surgical item:
a) in an emergency
b) when accidentally contaminated, or
c) when other means of sterilisation unavailable
December 1, 2013
Flash Sterilisation
• Never to be used for implantable items or to
compensate for shortage of key instruments
42
• Require hot-air ovens
• For glassware, metallic items, powders and
oil/grease
• Time two hours at 160°C and one hour at 180°C
• Plastics, rubber, paper and cloth cannot be
placed in them due to fire risk
December 1, 2013
Dry Heat Sterilisation - 1
43
Advantages
• Can be used for powders, anhydrous oils
• Inexpensive
• No corrosive effect on instruments
December 1, 2013
Dry Heat Sterilisation - 2
Disadvantages
• High temperature damages some items
• Penetration of heat slow, uneven
44
• Colourless, flammable, explosive and toxic gas
• Processing cycles overnight or longer
• Parametric release is not possible
December 1, 2013
Ethylene Oxide (EO)
• EO and relative humidity cannot readily be measured
• Spores of Bacillus atrophaeus used as biological
indicators to monitor process
45
• Used for heat or moisture sensitive
items
• Prevents normal cellular metabolism
and replication
December 1, 2013
Ethylene Oxide (EO)
Gas Sterilisation
46
•
•
•
•
Advantages
Items not damaged
by heat or moisture
Not corrosive, not
damaging to delicate
instruments, scopes
Permeates porous
materials
Dissipates from
material
•
•
•
•
Disadvantages
Cost
Toxic properties of
ethylene oxide
Aeration required
Longer process
December 1, 2013
EO Sterilisation
47
• Highly reactive/charged particles from
hydrogen peroxide generated under
vacuum
• Can be used to sterilise heat- and
moisture-sensitive items
December 1, 2013
Hydrogen Peroxide Gas Plasma
• Some plastics, electrical/electronic devices, and
corrosion-susceptible metal alloys
• Not compatible with cellulose (linen,
paper), devices with dead-end lumens,
powders and liquids
• Special wrapping required
48
• For rooms contaminated with some pathogens
• Such as MRSA and Clostridium difficile
• Release of hydrogen peroxide, chlorine dioxide
gas or possibly ozone in sealed rooms
• Spore strips (biological indicators) placed
strategically to monitor process
• Special equipment required
• Risk of damage to sensitive items
December 1, 2013
Fumigation
49
• Semi-critical items can be pasteurised
• 65-77°C, 30 min
• Example: respiratory therapy equipment
December 1, 2013
Pasteurisation and Boiling
• Must be retrieved carefully for safe
transport and storage
50
• Removal of microbes from air or
heat-sensitive liquids
• Disinfectant-impregnated filters
may inactivate trapped
microorganisms
• Example: High-efficiency particulate
air (HEPA) filters
• All filters must be checked for
integrity and replaced as necessary
December 1, 2013
Filtration
51
• Alternative to manual reprocessing of
heat-sensitive devices
• Minimise exposure of staff to pathogens
and disinfectants
• Require access to reliable electric and
water supplies, specific chemicals, regular
maintenance
• Biofilm build-up must be avoided
December 1, 2013
Automated Endoscope
Reprocessors
52
• UV lamps useful for chemical-free disinfection of
air and water and also possibly for
decontamination of environmental surfaces
• Broad-spectrum microbicidal action
• Require regular cleaning and periodic
replacement
December 1, 2013
Ultraviolet (UV) Light
53
• Heating from rapid rotation of water molecules
• Limited use except for disinfecting soft contact
lenses and urinary catheters for intermittent selfcatheterisation
• May be used in emergencies to treat water for
drinking or to ‘disinfect’ small water-immersible
plastic or glass items
December 1, 2013
Microwaves
54
Recommended practices state that both
biological and chemical indicators shall be used
to monitor the sterilisation process
December 1, 2013
Sterilisation Process Monitoring
• Mechanical monitoring
• Chemical monitoring
• Biological monitoring
55
• External Chemical Indicator
• process indicator - autoclave tape
• distinguishes processed from unprocessed medical
devices
• secures pack
• labels pack
December 1, 2013
Chemical Indicators
• Check external indicator to ensure it has
changed color before using any package
• If the indicator did not change, do not use
56
• Requires routine monitoring daily
• Test must be dated and labeled
• Once removed from the steriliser the test pack
opened, BI labeled, crushed and incubated in the
incubator
• Records of time, date of incubation and staff
initials is required and then time and date and
initials of the staff reading the final BI result
December 1, 2013
Biological Indicators
57
• Steam
Geobacillus stearothermophilus
• Dry heat B.atrophaeus (formerly B.subtilis)
• EO
B.atrophaeus
• New low temperature sterilisation technologies
December 1, 2013
Biological Monitoring
• Plasma sterilisation (Sterrad) B.atrophaeus
• Peracetic acid - Geobacillus stearothermophilus
58
• Development of reprocessing protocols for
instruments and equipment based on generally
recognised standards and manufacturer's
recommendations
• Use of clean water for cleaning items thoroughly
• Maintenance, use, and monitoring of equipment,
e.g., autoclaves
• Discarding items that cannot be cleaned or
reprocessed adequately
• Storing reprocessed items away from potential
sources of contamination
December 1, 2013
Main IP&C priorities
59
• Guidelines for Environmental Infection Control in HealthCare Facilities. MMWR 2003; 52(RR10):1-42.
http://www.cdc.gov/hicpac/pdf/guidelines/eic_in_HCF_0
3.pdf
• 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, 2010.
http://www.publichealthontario.ca/en/BrowseByTopic/In
fectiousDiseases/PIDAC/Pages/PIDAC_Documents.aspx
December 1, 2013
References - 1
60
• Rutala WA, Weber DJ. Guideline for Disinfection and
Sterilization in Healthcare Facilities, 2008. Centers for
Disease Control and Prevention, Atlanta, GA.
http://www.cdc.gov/hicpac/pdf/guidelines/Disinfection_
Nov_2008.pdf
• Snyder, OP. Calibrating thermometers in boiling water:
Boiling Point / Atmospheric Pressure / Altitude Tables.
http://www.hi-tm.com/Documents/Calib-boil.html
• Sattar A. Allen Denver Russell Memorial Lecture, 2006.
The use of microbicides in infection control: a critical
look at safety, testing and applications. J Appl Microbiol
2006; 101:743-753.
December 1, 2013
References - 2
61
1. Decontamination results in an item that is safe for patient
reuse. True/False.
2. Disinfection:
a.
b.
c.
d.
Is used for items that will contact intact skin
Involves chemical agents
Reduces the numbers of microorganisms
All of the above
December 1, 2013
Quiz
3. The most reliable means of sterilisation is:
a.
b.
c.
d.
Ethylene oxide
Steam
Dry heat
Plasma
62
• 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 to http://theific.org/
December 1, 2013
International Federation of
Infection Control
63