Transcript antiseptics and disinfectants

DISINFECTANTS
Sterlization
• Freeing of an article, surface or medium by
removing or killing all micro-organisms including
vegetative form of bacteria, spores, viruses, fungii
Disinfection
• Destruction or inhibition of growth of all pathogenic
organisms (bacteria, viruses, fungii) on non living
surfaces
• If spores are also killed process is Sterlization
Antiseptics
• These are chemical substances
which inhibit the growth or kill micro-organisms on
living surfaces such as skin & mucous membrane.
Properties of good antiseptic/
disinfectant
1.
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3.
4.
5.
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8.
Cidal
Non staining & good odour
Active against all pathogens
Active in presence of pus, blood & exudates
Rapid acting
Non irritating to tissues / non corrosive
Non absorbable
Non sensitizing/
Mechanisms of action of antiseptic
and disinfectants
• Oxidation of bacterial protoplasm
– Potassium permagnate, H202, Halogens
• Co-agulation (denaturation) of bacterial
proteins & disrupt cell membrane
– Phenols, chlorhexidine, alcohols, aldehydes
• Detergent like action ↑ permeability of
bacterial cell membrane
– Cetrimide, soaps
Classification
• Phenol derivatives:
– phenol, cresol, hexachlorophene,
chlorohexylenol (dettol)
• Oxidizing agents:
– Hydrogen peroxide.
• Halogens:
– Iodine, chlorine, chlorophores.
• Biguanides:
– Chlorhexidine.
• Quaternary ammonium:
– Cetrimide.
• Alcohols:
– Ethanol, isopropanol
• Aldehyde:
– Formaldehyde
• Acids:
– Acetic acid, boric acid
• Metallic salt:
– Mercuric compounds , silver
& zinc salts
• Dyes:
– Gentian violet, acriflavine
Phenol
• Earliest used, reference standard
• Protoplasmic poison,
– injures tissues & cells at high conc causes skin
burn
• MOA:
– denaturating bacterial protiens.
• USES :
– To disinfect urine, faeces, pus, burns.
• Extremely irritating, corrosive
CRESOL (Lysol)
• Methyl Derivative of phenol, less damaging
to tissues than phenol.
• 3-10 times more active
• used for disinfection of utensils, excreta &
for washing hands.
Chloroxylenol (Dettol)
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Phenol derivative
Does not co-agulate proteins,
Non corrosive,Non irritating to skin
Commercial 4.8 % solution used for surgical
antisepsis
• Skin cream and soap: 0.8%
• Mouth wash 1%
Hexachlorophene
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Commonly incorporated in soap
Effectively only against Gm+ve
Slow but persistant action
>2% preparations banned
Oxidizing agents
• Potassium permagnate:
– Purple crystals, highly water soluble, liberates
oxygen which oxidizes bacterial protoplasm.
– Used for gargling, irrigating wounds, urethra
(condy`s lotion diluted solution of 1:4000 to
1:10,000 )
– High conc cause burns
– It is also used to disinfect water in ponds.
– Stomach wash in alkaloidal poisoning
Oxidizing agents
Hydrogen Peroxide
– liberates nascent oxygen which oxidizes necrotic
matter & bacteria.
– Helps in loosening & removing slough, ear wax
etc.
Benzoyl Peroxide
– Widely used drug for acne.
– liberates O2 in presence of water which kills
bacteria, specially anaerobes
Halogens
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Iodine,
Iodophores,
Chlorine,
Chlorophores
Iodine
• Rapidly acting broad spectrum (bacteria,
fungi,virus)
• Acts by iodinating and oxidizing microbial
protoplasm.
• Used for cuts, degerming skin beforesurgery.
• Adverse effect: cause burns & blisters
Iodophores
• Known as povidine iodine.
• Non toxic, non staining prolonged action.
• Used on boils, furunculosis, burns, ulcers,
tinea, surgical srub, disinfecting surgical
instruments, non specific vaginitis.
Chlorine
• potent germicide. Kills pathogens in 30 sec.
used to disinfect urban water supplies.
• 0.1 to 0.25 ppm
Cholorophores
(1) Chlorinated lime (bleaching powder)
– obtained by action of chlorine on lime.
– used to disinfect drinking water
(2) Sodium hypochlorite
– Powerful disinfectant used in dairies for milk
cans.
– Too Irritant to be used as antiseptic.
– Root canal therapy in dentisry
Biguanides
Chlorhexidine: (Savlon)
– Acts by disrupting bacterial cell membrane &
denaturation of bacterial proteins
– Non irritant ,more active against gram +ve
bacteria.
– Used in for surgical scrub, neonatal bath, mouth
wash & general skin antiseptic.
– Most widely used antiseptic in dentisry 0.12-0.2%
oral rinse or 0.5 -1 % tooth paste
Quarternary ammonium antiseptics
cetrimide
• Detergents: Cidal to bacteria, fungi & viruses.
• Act by altering permeability of cell membrane
• Efficiently remove dirt and grease
• Widely used as antiseptics & disinfectants for
surgical instruments, gloves etc
• Combined with chlorhexidine (savlon)
Soaps
• Anionic detergents
• Weak antiseptics with cleansing action
• Washing with soap and warm water one of
the most effective methods of preventing
disease transmission
• Affect only Gm+ bacteria
Alcohols
• Ethanol
– Antiseptic, cleansing agent at 40-90% conc.
– Act by precipating bacterial proteins
– Irritant, should not be applied on mucous
membrane, ulcers, open wounds.
Aldehydes (Formaldehyde)
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Used for fumigation.
37 % aqueous solution called as formalin.
Protoplasmic poison , denaturates protiens.
Used for preserving dead tissues.
Use as antiseptic restricted due to bad odour
& irritation
• Glutaraldehyde is a better sterlizing agent
Acids
Boric acid
• weak antiseptic , bacteriostatic.
• used for mouth wash, irrigation eyes, glossitis.
• Adverse effect: vomiting ,abdominal pain on
systemic absorption.
Metallic salts
SILVER COMPOUNDS
• Silver sulphadiazine is active against
pseudomonas seen in burns patient.
• Silver nitrate highly active against gonococci
ZN SALTS
• Mild antiseptic, used as eye wash, ear drops.
Dyes
Gentian violet:
– Active against bacteria (gram + ve), fungi
– Used on chronic ulcers, furunculosis, bed sores,
ring worms.
Acriflavine
– Active against gram +ve bacteria & gonocci
– suitable for chronic ulcers & wounds
– Do not retard healing, non irritant
Ectoparasiticides
• These are drugs used to kill parasites that live
on body surfaces
lice → cause pediculosis (hair infection)
mites → cause scabies(skin infection)
Drugs used are
(1) PERMETHRIN
(2) LINDANE
(3) BENZYL BENZOATE
(4) IVERMECTIN
(5) CROTAMITON
(6) SULFUR
Permethrin
• Broad spectrum causes neurological paralysis in
insects.
• 100 % cure rate nearly
• Single application needed in most cases.
• Few patients experience itching ,burning.
• first drug of choice for scabies & pediculosis.
Scabies: apply all over the body except face &
head . Wash after 8- 12 hrs.
Head louse: massage about 30 g in to scalp and
wash after 10 min.
Lindane
• Broad spectrum insecticide which kills lice and
mites by penetrating their chitinous cover
• Properties similar to permethrin.
• Cure rate low & resistance seen.
• Disadvantage: being lipid soluble CNS toxicity like
vertigo , convulsions seen.
• Application similar to permithrin.
• combination with benzyl benzoate is more
effective.
Benzyl benzoate
• Oily liquid with aromatic smell.
• Cure rate 76 – 100% ; second application required
after 24 hrs.
• Toxicity is low. Application similar to permethrin.
• Use has declined due to skin irritation.
• Contra indicated in children because of
neurological symptoms & skin irritation.
• combination with lindane highly effective.
Crotamiton
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low cure rates
Better results if applied for 5 days in children
Less irritation and toxicity
May be preferred in children as second choice
Ivermectin
• Anti helminthic drug which has been recently
found effective against scabies & pediculosis.
• A single 0.2 mg /kg ( 12mg in adults) has 91100 % cure rate.
• Contra indicated in children  5yrs ,
preganant & lactating women.
• Disinfection may be defined as: Cleaning an article of
some or all of the pathogenic organisms which may
cause infection
• Perfect disinfectant would also offer complete and
full sterilization, without harming other forms of life,
be inexpensive, and non-corrosive. Unfortunately
ideal disinfectants do not exist. Most disinfectants
are also, by their very nature, potentially harmful
(even toxic) to humans or animals.
Cleaning
• Cleaning - the physical removal of foreign material,
e.g., dust, soil, organic material such as blood,
secretions, excretions and microorganisms. Cleaning
generally removes rather than kills microorganisms.
It is accomplished with water, detergents and
mechanical action. The terms “decontamination” and
“sanitation” may be used for this process in certain
settings, e.g., central service or dietetics. Cleaning
reduces or eliminates the reservoirs of potential
pathogenic organisms
Decontamination
• Decontamination: the
removal of
disease-producing
microorganisms to
leave an item safe
for further
handling
Disinfection
• Disinfection: the inactivation of diseaseproducing microorganisms. Disinfection does
not destroy bacterial spores. Disinfectants are
used on inanimate objects in contrast to
antiseptics, which are used on living tissue.
Disinfection usually involves chemicals, heat
or ultraviolet light. The nature of chemical
disinfection varies with the type of product
High level disinfection
• High level disinfection processes destroy
vegetative bacteria, mycobacteria, fungi and
enveloped (lipid) and nonenveloped (non
lipid) viruses, but not necessarily bacterial
spores. High level disinfectant chemicals (also
called chemical sterilants) must be capable of
sterilization when contact time is extended.
Items must be thoroughly cleaned prior to
high level disinfection.
Intermediate level disinfection:
• Intermediate level
disinfectants kill
vegetative
bacteria, most
viruses and most
fungi but not
resistant bacterial
spores.
Low level disinfection
• Low level disinfectants kill most vegetative
bacteria and some fungi as well as enveloped
(lipid) viruses (e.g., hepatitis B, C, hantavirus,
and HIV). Low level disinfectants do not kill
mycobacteria or bacterial spores. Low level
disinfectants are typically used to clean
environmental surfaces.
Chemical Methods
• Disinfectants and
antiseptics
• Surface-active agents
(surfactants)
• Chemical food
preservatives
• Aldehydes
• Gas sterilization
• Oxidizing agents
• [Antibiotics]
Disinfectants
• Kill/inhibit growth of microbes on surfaces
• Phenols and phenolics: damage lipid membranes
Active in presence of organic matter
– Stable
– Persist for long periods after application
–
Antiseptics
• Biguanides:
Chlorhexidine
• Low toxicity
–Used on skin
and mucous
membranes
Antiseptics
• Alcohol : protein
denaturation and
membrane damage
– evaporate quickly
– ethanol and isopropanol
– [not effective if taken
internally]
Disinfectants
• Halogens: iodine and chlorine
– Iodine used in solution : Betadine® and Isodine®
– Chlorine is a gas that forms bleach (hypochlorite)
in water
– Chloramines are chlorine and ammonia
Sterilization – An absolute Procedure
• The destruction of all
forms of microbial life
including bacteria,
viruses, spores and
fungi. Items should be
cleaned thoroughly
before effective
sterilization can take
place.
Noncritical items
• That either come in
contact with only intact
skin but not mucous
membranes or do not
directly contact the
patient. Reprocessing of
noncritical items
involves cleaning and/or
low level disinfection
Sanitation
• Process that reduces
microorganisms on an
inanimate object to a
level below that of
infectious hazard (e.g.,
dishes and eating
utensils are sanitized
Semi critical items
• Devices that come in
contact with no intact skin
or mucous membranes but
ordinarily do not penetrate
them. Reprocessing semi
critical items involves
meticulous cleaning
followed preferably by
high-level disinfection
Disinfectant effectiveness depends on
many factors.
•
Type of contaminating microorganism. Each disinfectant has unique antimicrobial
attributes.
•
• Degree of contamination. This determines the quality of disinfectant required
and time of exposure.
•
• Amount of proteinaceous material present. High protein based materials
absorb and neutralize some chemical disinfectants.
•
• Presence of organic matter and other compounds such as soaps may neutralize
some disinfectants.
•
• Chemical nature of disinfectant. It is important to understand the mode of
action in order to select the appropriate disinfectant.
Disinfectant effectiveness depends on
many factors.
•
Concentration and quantity of disinfectant. It is important to choose the proper
concentration and quantity of disinfectant that is best suited to each situation.
•
• Contact time and temperature. Sufficient time and appropriate temperature
must be allowed for action of the disinfectant and may depend on the degree of
contamination and organic matter load.
•
• Residual activity and effects on fabric and metal should be considered for
specific situations.
•
• Application temperature, pH and interactions with other compounds must be
considered.
•
• Toxicity to the environment and relative safety to people that may be exposed.
• • Cost.
•
5
Microbial Characteristics and Microbial
Control
Figure 7.11
PHENOLICS
• Examples: Benzyl-4-chlorophenol, Amyl
phenol, Phenyl phenol
• Advantages and disadvantages: good general
purpose disinfectants, not readily inactivated
• by organic matter, active against wide range of
organisms (including mycobacterium), but not
sporicidal.
Phenol as Disinfectant
• Phenolic disinfectants are
effective against bacteria
(especially gram positive
bacteria) and enveloped
viruses. They are not
effective against
nonenvelopedd viruses and
spores. These disinfectants
maintain their activity in the
presence of organic
material.
Phenol as Disinfectant
• They are not effective
against nonenvelopedd
viruses and spores. These
disinfectants maintain their
activity in the presence of
organic material. This class
of compounds is used for
decontamination of the
hospital environment,
including laboratory
surfaces, and noncritical
medical items
Phenol as Disinfectant
• Phenolics are not
recommended for semi
critical items because of the
lack of validated efficacy
data for many of the
available formulations and
because the residual
disinfectant on porous
materials may cause tissue
irritation even when
thoroughly rinsed.
Alcohols
• “Alcohol" refers to two water-soluble chemicals:
ethyl alcohol and isopropyl alcohol. These alcohols
are rapidly bactericidal rather than bacteriostatic
against vegetative forms of bacteria (Gram + and
Gram -); they also are tuberculocidal, fungicidal, and
virucidal against enveloped viruses. Alcohols are not
effective against bacterial spores and have limited
effectiveness against nonenveloped viruses
Alcohols
• Their cidal activity drops
sharply when diluted below
50% concentration and the
optimum bactericidal
concentration is in the
range of 60-90% solutions in
water (volume/volume).
The antimicrobial activity of
alcohols can be attributed
to their ability to denature
proteins.
Alcohols
• Higher
concentrations are
less effective as the
action of denaturing
proteins is inhibited
without the
presence of water
Alcohols
• Alcohols are commonly
used topical antiseptics.
They are also used to
disinfect the surface of
medical equipment.
Alcohols require time to
work and they may not
penetrate organic
material.
Alcohols
• They also evaporate rapidly
which makes extended
exposure time difficult to
achieve unless the items are
immersed. Alcohol irritates
tissues. They are generally
too expensive for general
use as a surface disinfectant
Soap, Water and common sense are yet
the best antiseptics
William Osler
Gaining importance in Hand Washing with
Alcohols
• The use of either ethyl
alcohol or isopropyl alcohol
in a 60-90% solution has
recently gained wide
acceptance in health care
settings as hand antiseptics.
They can be used as a
reasonable substitute for
handwashing as long as
hands are not visibly soiled
Hypochlorite's
• Hypochlorites are the most widely used of the
chlorine disinfectants and are available in a
liquid (e.g. sodium hypochlorite) or solid (e.g.
calcium hypochlorite, sodium
dichloroisocyanurate) form. The most
common chlorine products in are aqueous
solutions of 4 to 6% sodium hypochlorite,
which are readily available as “household
bleach”.
Hypochlorite's
• They have a broad
spectrum of
antimicrobial activity,
are unaffected by water
hardness, are
inexpensive and fast
acting, and have a low
incidence of serious
toxicity
Hypochlorite's
• Other disadvantages of
hypochlorites include
corrosiveness to metals in
high concentrations (>500
ppm), inactivation by
organic matter, discoloring
or “bleaching” of fabrics,
and release of toxic chlorine
gas when mixed with
ammonia or acid.
Hypochlorite's
• Hypochlorites can eliminate both enveloped and
nonenveloped viruses if used in correct dilution and
contact time. They are also is effective against fungi,
bacteria, and algae but not spores. Household bleach
is typically diluted using 1:50 with water (1000ppm)
for surface disinfection. Bleach solutions have been
recommended for use in both hospitals and the
community as disinfecting solutions.
Hypochlorite's Most recommended in
• They are included
in most
recommendation
for
decontamination
of hepatitis and
AIDS viruses
Hypochlorite's
• Hypochlorites are also the
agent of choice in
disinfecting surfaces used
for food preparation or in
bathrooms. Organic
material such as feces or
blood inactivate chlorine
based disinfectants,
therefore, surfaces must be
clean before their use.
Hypochlorite's
• Chlorinated drinking
water should not
exceed 6 to 10 ppm of
free chlorine with the
lower value being in
continuous flow or low
volume reservoir
systems.
Iodine And Iodophor Disinfectants
• These compounds have
been incorporated in time
release formulations and in
soaps (surgical scrubs).
Simple iodine tinctures
(dissolved in alcohol) have
limited cleaning ability.
These compounds are
bactericidal, sporicidal,
virucidal and fungicidal but
require a prolonged contact
time.
Iodine And Iodophor Disinfectants
• Besides their use as an
antiseptic, iodophors
have been used for the
disinfection of blood
culture bottles and
medical equipment
such as hydrotherapy
tanks, thermometers,
and endoscopes
Iodine And Iodophor Disinfectants
• The disinfective ability of
iodine, like chlorine, is
neutralized in the presence
of organic material and
hence frequent applications
are needed for thorough
disinfection. Iodine
tinctures can be very
irritating to tissues, can
stain fabric and be
corrosive.
Hydrogen Peroxide
• Peroxides such as hydrogen peroxide are often
used as antiseptics to clean wounds. The
activity of peroxides is greatest against
anaerobic bacteria. Hydrogen peroxide at high
concentrations is in some cases is damaging to
tissues, resulting in a prolonged healing time.
It is useful for cleaning surgical sites after
closure, but use sparingly to avoid penetrating
suture lines, which would inhibit healing.
Hydrogen Peroxide
• Stabilized hydrogen
peroxides can be used to
disinfect environmental
surfaces. The literature
contains several accounts of
the properties, germicidal
effectiveness, and potential
uses for stabilized hydrogen
peroxide in the hospital
setting
Hydrogen Peroxide
• Stabilized peroxides
may also be blended
with iodophors or
quaternary ammonia.
Hydrogen peroxide is
also blended with
paracetic acid in high
concentrations for use
as a high-level
disinfectant
Gluteraldehyde
• Aldehydes have a wide
germicidal spectrum.
Gluteraldehydes are
bactericidal, virucidal,
fungicidal, sporicidal and
parasiticidal. They are used
as a disinfectant or sterilant
in both liquid and gaseous
forms. They have moderate
residual activity and are
effective in the presence of
limited amounts of organic
material
Formaldehyde
• Gluteraldehydes are very
potent disinfectants, which
can be highly toxic. Use
them only as a last resort
and then under trained
supervision in a wellventilated setting and with
appropriate personal
protective equipment.
Formaldehyde
• Formaldehyde is used as a
disinfectant and sterilant
both in the liquid and
gaseous states.
Formaldehyde is sold and
used principally as a waterbased solution called
formalin, which is 37%
formaldehyde by weight.
The aqueous solution is
bactericidal, tuberculocidal,
fungicidal, virucidal and
sporicidal
Formaldehyde
•
Formaldehyde should be handled in
the workplace as a potential
carcinogen with an employee
exposure standard that limits an 8
hour time-weighted average
exposure to a concentration of 0.75
ppm. For this reason,
employees should have
limited direct contact with
formaldehyde and these
considerations limit its role
in sterilization and
disinfection processes
Ortho-phthalaldehyde
• Ortho-phthalaldehyde (OPA) is a chemical sterilant
similar to Gluteraldehydes with similar antimicrobial
activity. OPA has several potential advantages
compared to Gluteraldehydes. It has excellent
stability over a wide pH range (pH 3-9), is not a
known irritant to the eyes and nasal passages, does
not require exposure monitoring, has a barely
perceptible odor, and requires no activation. OPA,
like Gluteraldehydes, has excellent material
compatibility
Ortho-phthalaldehyde
• A potential disadvantage of OPA is that it
stains proteins gray (including unprotected
skin) and thus must be handled with caution.
However, skin staining would indicate
improper handling that requires additional
training and/or personal protective equipment
(PPE) (gloves, eye and mouth protection, fluidresistant gowns).
Per acetic Acid
• Peracetic, 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
Per acetic Acid
• It is used in automated
machines to chemically
sterilize medical,
surgical, and dental
instruments (e.g.,
endoscopes,
arthroscopes).
Per acetic Acid and Hydrogen Peroxide
• 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).
The bactericidal properties of peracetic acid
and hydrogen peroxide have been established.
Per acetic acid and hydrogen peroxide useful in
Hemodialyzers
• Findings demonstrated that
this product inactivated all
microorganisms with the
exception of bacterial
spores within 20 minutes.
The combination of per
acetic acid and hydrogen
peroxide has been used for
disinfecting hem dialyzers.
Quaternary Ammonium Compounds
• The quaternaries are good cleaning agents but
high water hardness and materials such as
cotton and gauze pads may make them less
microbiocidal because these materials absorb
the active ingredients. As with several other
disinfectants (e.g., phenolics, iodophors)
gram-negative bacteria have been found to
survive or grow in these preparations
Quaternary Ammonium Compounds
• They are not effective against non-enveloped viruses,
fungi and bacterial spores. QA disinfectants carry a
very strong positive charge that makes good contact
with negatively charged surfaces. This characteristic
makes most very good cleaning agents. QA
compounds are generally low in toxicity, but
prolonged contact can be irritating. The quaternaries
are commonly used in ordinary environmental
sanitation of noncritical surfaces such as floors,
furniture, and walls
Work with Caution
• A wide range of microorganisms is destroyed
by varying concentrations of aqueous
formaldehyde solutions. Although
formaldehyde-alcohol is a chemical sterilant
and formaldehyde is a high-level disinfectant,
the hospital uses of formaldehyde are limited
by its irritating fumes and the pungent odor
that is apparent at very low levels (<1 ppm).
What is Gas Plasma STERILIZATION
• Plasma is a fourth state of matter which is
distinguishable from liquid, solid, or gas. In
nature, plasma is widespread in outer space.
• Gas plasma generated in an enclosed chamber
under deep vacuum using Radio frequency or
Microwave emery to excite gas molecules are
produced charged particles
How Gas Plasma works.
• Many particles are in the form of free radicals
• A free radical is an Atom with an unpaired electron
and is a highly reactive species
• The mechanism of action of this device is the
production of free radicals within a plasma field that
are capable of interacting with essential cell
components, ie is enzymes and nucleic acids. And
thereby disrupt the metabolism of microorganisms.
Gas Plasma - Sterilization
• Plasma sterilization
operates differently
because of its specific active
agents, which are
ultraviolet (UV) photons and
radicals (atoms or assembly
of atoms with unpaired
electrons, therefore
chemically reactive, e.g., O
and OH, respectively
BASIC MECHANISMS OF PLASMA
STERILIZATION
• Destruction by UV irradiation of the genetic
material of the microorganism; this is a
statistical process requiring a sufficient
number of lesions of the DNA strands.
• Erosion of the microorganism, atom by atom,
through intrinsic photo desorption
Advantage of the plasma method
• An advantage of the plasma method is the
possibility, under appropriate conditions, of
achieving such a process at relatively low
temperatures (≤50 °C), preserving the
integrity of polymer-based instruments, which
cannotbe subjected to autoclaves and ovens
Furthermore, plasma sterilization is safe, both
for the operatorand the patient, in contrast to
EtO.
Hydrogen Peroxide Sterilization Offers Fast
Cycle Times
• Benefits of gas plasma
(vaporized hydrogen
peroxide) sterilization
are fast cycle times, the
absence of toxic
residuals, and a lowmoisture environment
not exceeding 50ºC, a
New CDC guidelines
Factors Related To Infection Risk
• Endoscope
contamination accounts
for more health care
related infections than
any other medical
instrument and is
responsible for
consequences ranging
from bacterial
colonization to death.
Disinfection and sterilization are affected
by
• Initial cleaning of the
device
• Physical complexity of
the device
Biofilms and microbial
load
• Microbe type and
quantity
• HLD exposure time and
concentration
When things go wrong
• Inadequate
cleaning
Using the wrong
disinfectant
• Failure to follow
procedures
Guideline Excerpts
Infection Risks
• “Multiple studies in many
countries have documented
lack of compliance with
established guidelines for
disinfection and
sterilization.
• Failure to comply with
scientifically-based
guidelines has led to
numerous outbreaks.
Biofilms interfere in effective
antimicrobial action
• “Biofilms are microbial
communities that are tightly
attached to surfaces and
cannot be easily
removed...Bacteria within
biofilms are up to 1,000
times more resistant to
antimicrobials than are the
same bacteria in suspension
Biofilms interfere in effective
antimicrobial action
• “One multistate
investigation found that
23.9% of the bacterial
cultures from the internal
channels of 71
gastrointestinal endoscopes
grew ≥100,000 colonies of
bacteria after completion of
all disinfection and
sterilization procedures