infection control

2. • referring to any process that eliminates (removes) or kills
(deactivates) all forms of life and other biological agents which
consider pathogens
• Sterilization can be achieved with one or more of the following
: heat, chemicals, irradiation, high pressure, and filtration.

3. 1. Render medical devices safe for patient use
2. Prevent infections
3. Minimize potential for infection
4. Prevent cross contamination
5. Provide consistent sterile processing procedures

4. • Disinfection describes a process that eliminates many or all
pathogenic microorganisms with the exception of bacterial
spores.

5. • Cleaning is the removal of visible soil (e.g., organic and
inorganic material) from objects and surfaces and normally is
accomplished manually or mechanically using water with
detergents or enzymatic products.
• Thorough cleaning is essential before high-level disinfection
and sterilization because inorganic and organic materials that
remain on the surfaces of instruments interfere with the
effectiveness of these processes. Decontamination removes
pathogenic microorganisms from objects so

6. • Instruments and items for patient care were divided into three
categories based on the degree of risk of infection involved in
the use of the items:
enters sterile tissue and must be sterile
2. contacts mucous membranes and requires
high-level disinfection
comes in contact with intact skin and requires
low-level disinfection

8. METHODS OF STERILIZATION

9. Process Level of Microbial
Inactivation
Method Examples
(with
processing times)
Healthcare
Application
(examples)
Sterilization Destroys all
microorganisms,
including bacterial
spores
High temperature Steam (~40 min) Heat-tolerant
critical (surgical
instruments) and
semicritical patient-
care items
Low temperature Ethylene oxide gas
(~15 hr), hydrogen
peroxide gas
plasma (28-52
min), ozone (~4 hr),
hydrogen peroxide
vapor (55 min)
Heat-sensitive
critical and
semicritical patient-
care items
Liquid immersion Chemical sterilants
hydrogen
peroxide 7.5% HP (6
hr)
>2% glutaraldehyde
(~10 hr)
Heat-sensitive
critical and
semicritical patient-
care items that can
be immersed

10. Process Level of Microbial
Inactivation
Method Examples
(with processing times)
Healthcare
Application
(examples)
High-level
disinfection (HLD)
Destroys all
microorganisms
except high
numbers of
bacterial spores
Liquid
immersion
0.55% OPA (12 min)
>2% glutaraldehyde (10-
90 min)
Heat-sensitive
semicritical items
(e.g., GI
endoscopes,
bronchoscopes,
endocavitary
probes)
Intermediate-level
disinfection
Destroys vegetative
bacteria,
mycobacteria, most
viruses, most fungi
but not bacterial
spores
Liquid contact EPA-registered hospital
disinfectant with label
claim regarding
tuberculocidal activity
(e.g., chlorine-based
products, phenolics,
improved hydrogen
peroxide-exposure times
at least 1 min)
Noncritical patient
care item (blood
pressure cuff) or
surface with visible
blood
Low-level
disinfection
Destroys vegetative
bacteria, some fungi
and viruses but not
mycobacteria or
spores
Liquid contact EPA-registered hospital
disinfectant with no
tuberculocidal claim (e.g.,
chlorine-based products,
phenolics, improved
Noncritical patient
care item (blood
pressure cuff) or
surface (bedside
table) with no visible

11. • There are several physical sterilization methods, the most
efficient of which combines heat with humidity and pressure in
a device called an autoclave.
• Autoclave Steam Sterilization
• is suited for objects that can tolerate humidity, high pressure (1
to 3.5 atmospheres above ambient), and high temperature
(+121°C to +148°C). Typical examples are surgical
instruments.
• The entire cycle can take from 15 to 60 minutes.

12. • a. Chemical Indicators
• Chemical Color Change Indicators
• Chemical indicators for steam autoclaving change colors after being
exposed for a few minutes to normal autoclave operating
temperatures of 121ºC
• . Chemical indicators should be positioned near the center of each
load, and toward the bottom front of the autoclave.
• Caution: Most chemical indicators can only be used to verify that your
autoclave has reached normal operating temperatures for
decontamination; they have no time factor. Chemical indicators alone
are not designed to prove that organisms are actually killed during a
decontamination cycle.
• b. Biological Indicators
• Biological indicators are designed to demonstrate that an autoclave is
capable of killing microorganisms.
• Follow the manufacturer’s instructions for the spore test.

13. a. Aldehydes:
Ortho-phthalaldehyde (OPA)
• An essential component of disinfection of reusable devices (e.G., Endoscopes).
• The time required for high-level disinfection of a medical device by OPA would be
less than 12 minutes.
Glutaraldehyde (cidex)
• high-level disinfectant and chemical sterilant
• is used most commonly as a high-level disinfectant for medical equipment such as
endoscopes spirometry tubing, dialyzers ,transducers, anesthesia and respiratory
therapy equipment, hemodialysis systems and reuse of laparoscopic disposable
plastic trocars .
• Glutaraldehyde is noncorrosive to metal and does not damage lensed instruments,
rubber. or plastics.
• Glutaraldehyde should not be used for cleaning noncritical surfaces because it is
too toxic and expensive.

14. b. Halogen-Based Biocides: (Chlorine Compounds and Iodophores)
Chlorine Compounds
• Chlorine compounds are good disinfectants on clean surfaces, but
are quickly inactivated by organic matter and thus reducing the
biocidal activity.
• They have a broad spectrum of antimicrobial activity and are
inexpensive and fast acting.
• Hypochlorites(clorex), the most widely used of the chlorine
disinfectants
• Because of its oxidizing power, it loses potency quickly and should
be made fresh
 Iodophors
• Iodophors (Betadyne, Povidone-Iodine)are used both as antiseptics
and disinfectants. An iodophor is a combination of iodine and a

15. • c. Quaternary Ammonium Compounds :
• Quaternary ammonium compounds are generally odorless, colorless,
nonirritating, and deodorizing.
• They also have some detergent action, and they are good
disinfectants.
• activity is reduced in the presence of some soaps or soap residues,
detergents, acids and heavy organic matter loads.
• They are generally ineffective against viruses, spores
and Mycobacterium tuberculosis. Basically these compounds are not
suitable for any type of terminal disinfection.
• these compounds are better used in water baths, incubators, and
other applications where halide or phenolic residues are not desired.

16. d. Alcohols:
• Alcohols work through the disruption of cellular membranes, solubilization
of lipids, and denaturation of proteins
• Ethyl and isopropyl alcohols are the two most widely used alcohols for their
biocidal activity.
• These alcohols are effective against some viruses and a broad spectrum of
bacterial species, but ineffective against spore-forming bacteria.
• They evaporate rapidly, which makes extended contact times difficult to
achieve unless the items are immersed.
• The optimum bactericidal concentration for ethanol and isopropanol is in
the range of 60% to 90% by volume.
• Their cidal activity drops sharply when diluted below 50% concentration.
• Absolute alcohol is also not very effective.
• They are used to clean instruments and wipe down interior of Biological
Safety Cabinets and bottles, etc. to be put into Biological Safety Cabinets.
Alcohols are generally regarded as being non-corrosive.

17. e. Acids/Alkalis:
• Hydrogen Peroxide
• Works by producing destructive hydroxyl free radicals that can attack
membrane lipids, DNA, and other essential cell components
• Hydrogen peroxide is active against a wide range of microorganisms,
including bacteria, yeasts, fungi, viruses, and spores
• It's used as high-level disinfectant (0.5 %-0.6% ) contact time 30-60
min.
• Concentrations of hydrogen peroxide from 6% to 25% show promise as
chemical sterilants and it has been used in for disinfecting soft contact
lenses (e.g., 3% for 2–3 hrs) , tonometer prisms ,ventilators , fabrics ,
and endoscopes.