تعقيم عيادات الاسنان 2

1. DISINFECTION AND STERILIZATION
IN HEALTH CARE
Dr.T.V.Rao MD

2. A Tribute to
Ignaz Semmelweiss (1818-1865)
Ignaz Semmelweiss (1818-
1865)
• Established that
high maternal
mortality was due
to failure of
doctors to wash
hands after post-
mortems
• Reduced maternal
mortality by 90%
Dr.T.V.Rao MD' TMC Kollam Kerala 2

3. What is Disinfection
• 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. Most disinfectants are
also, by their very nature, potentially
harmful (even toxic) to humans or animals.
Dr.T.V.Rao MD 3

4. What is the Best Choice in
Disinfection Practices

5. The Ideal Disinfectant
 Resistant to inactivation
 Broadly active (killing pathogens)
 Not poisonous (or otherwise harmful)
 Penetrating (to pathogens)
 Not damaging to non-living materials
 Stable
 Easy to work with
 Otherwise not unpleasantDr.T.V.Rao MD 5

6. Terminology
• Antisepsis: chemical destruction of
vegetative pathogens on living
tissue
• Degerming: mechanical removal of
microbes from limited area
• Sanitization: lowering microbial
counts on eating and drinking
utensils to safe levels
Dr.T.V.Rao MD 6

7. Terminology
• Biocide or germicide: kills
microorganisms
• Fungicide: kills fungi
• Virocide: inactivates viruses
• Bacteriostatic agent: stops
growth of bacteria
Dr.T.V.Rao MD 7

8. Antiseptics versus Disinfectants
Antiseptics:
Use on skin and mucous membranes to kill
microorganisms
Not for use on inanimate objects
Disinfectants:
Use to kill microorganisms on inanimate objects
Not for use on skin or mucous membranes
High-level versus low-level disinfectants
Dr.T.V.Rao MD 8

9. Beginning of Scientific era of sterilization and
Disinfection
Dr.T.V.Rao MD 9

10. Disinfection x Sterilization
• Sterilization is absolute,
removes microbes and
spores too.
• To achieve Sterilization
is Expensive, not
sustainable, many
times not needed.
• An effective
Disinfection reduces
the infections
drastically.
Dr.T.V.Rao MD 10

11. • Process of
destroying all
microbial forms. A
sterile object is
one free of all
microbial forms,
including bacterial
spores.
• More thorough
than disinfection
Sterilization
Dr.T.V.Rao MD 11

12. • Process of reducing or
eliminating living
pathogenic
microorganisms in or
on materials, so they
are no longer a health
hazard.
For example: use
of alcohol before
drug injection.
Disinfection
Dr.T.V.Rao MD 12

13. Soaps are
sodium or
potassium salts
of fatty acids, a
natural product
Detergents,
instead, are
artificial
surfactants
Soap and detergents
Dr.T.V.Rao MD 13

14. Halogens
 Halogens are the seventh (VII) column of the periodic table of
elements
 Two halogens are regularly employed as antimicrobials: Iodine
and Chloride
 Iodine: commonly used as an antiseptic against all microbes,
fungi, and viruses
 Iodine: It inhibits protein synthesis and oxidizes –SH groups of
amino acids
 Chlorine: Used as a disinfectant (10% bleach)
 Chlorine: Hypochlorous acid (HOCl) is a product, formed in water,
that is the active form of the disinfectant
 Chlorine: Applied in treatment of drinking water, swimming pool,
and sewage Dr.T.V.Rao MD 14

15. 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. Dr.T.V.Rao MD 15

16. 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.
Dr.T.V.Rao MD 16

17. 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.
Dr.T.V.Rao MD 17

18. 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
Dr.T.V.Rao MD 18

19. 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. Dr.T.V.Rao MD 19

20. 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.
Dr.T.V.Rao MD 20

21. 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
Dr.T.V.Rao MD 21

22. 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
Dr.T.V.Rao MD 22

23. 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
Dr.T.V.Rao MD 23

24. Hypochlorite's
• Other disadvantages of
hypochlorite's 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.
Dr.T.V.Rao MD 24

25. Hypochlorite's
• Hypochlorite's 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.
Dr.T.V.Rao MD 25

26. Hypochlorite's Most recommended in
• They are
included in most
recommendatio
n for
decontaminatio
n of hepatitis
and AIDS viruses
Dr.T.V.Rao MD 26

27. 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.
Dr.T.V.Rao MD 27

28. HIGH LEVEL DISINFECTANTS
Dr.T.V.Rao MD 28

29. 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.
Dr.T.V.Rao MD 29

30. 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 Dr.T.V.Rao MD 30

31. 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
well-ventilated setting
and with appropriate
personal protective
equipment.
Dr.T.V.Rao MD 31

32. Formaldehyde
• Formaldehyde is used
as a disinfectant and
sterilant both in the
liquid and gaseous
states. Formaldehyde is
sold and used
principally as a water-
based solution called
formalin, which is 37%
formaldehyde by
weight. The aqueous
solution is bactericidal,
tuberculocidal, fungicidal,
virucidal and sporicidal Dr.T.V.Rao MD 32

33. 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
Dr.T.V.Rao MD 33

34. Glutaraldehyde
• 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. Dr.T.V.Rao MD 34

35. Ethylene oxide
Dr.T.V.Rao MD 35
• Ethylene oxide, also called oxirane, is the
organic compound with the formula C2H4O.
It is a cyclic ether. This means that it is
composed of two alkyl groups attached to
an oxygen atom in a cyclic shape (circular).
This colorless flammable gas with a faintly
sweet odor is the simplest epoxide, a three-
membered ring consisting of two carbon
and one oxygen atom.

36. • Highly effective
against most
microbes
• Highly diffusive
• Compatible with a
wide variety of
materials in
devices and
packaging
Ethylene oxide ADVANTAGES

37. • Complex process
• Longer turn-around
times
– BI Testing
– Residual dissipation
• Safety concerns
– Flammable
– Explosive
• OSHA concerns
– Carcinogen
• EPA concerns
– Emissions
Ethylene oxide DISADVANTAGES

38. 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
Dr.T.V.Rao MD 38

39. • Per acetic, or
peroxyacetic, acid is
characterized by a very
rapid action against all
microorganisms. A special
advantage of per acetic
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
Dr.T.V.Rao MD 39

40. Per acetic Acid and Hydrogen
Peroxide
• Two chemical sterilants are available
that contain per acetic acid plus
hydrogen peroxide (0.08 per acetic acid
plus 1.0% hydrogen peroxide [no longer
marketed], 0.23% per acetic acid plus
7.35% hydrogen peroxide). The
bactericidal properties of per acetic
acid and hydrogen peroxide have been
established. Dr.T.V.Rao MD 40

41. Per acetic acid and hydrogen peroxide
useful in Hem dialyzers
• 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 Dr.T.V.Rao MD 41

42. 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 microbicidal
because these materials absorb the
active ingredients. As with several other
disinfectants (e.g., phenolic, Iodophor)
gram-negative bacteria have been found
to survive or grow in these preparationsDr.T.V.Rao MD 42

43. Dr.T.V.Rao MD 43
Which Skin Preparation Agent is Superior
• Researchers conducted a review of surgical
skin prep agents to conclude which agent
was most cost-effective and superior in
preventing surgical site infections. Based on
information collected from two databases,
researchers compared povidone-iodine,
Chlorhexidine gluconate, parachoroxylenol
and iodine povacrylex (0.7 percent available
iodine) in 74 percent isopropyl alcohol
(DuraPrep). Researchers concluded that
each prep agent has specific advantages and
disadvantages and no one skin prep agent is
superior in all clinical situations. Factors to
consider when choosing a skin prep agent
include surgeon preference and
environmental risks.

44. Fumigation
a biohazard procedure ?
Dr.T.V.Rao MD 44

45. What Is Formaldehyde?
Dr.T.V.Rao MD 45
• Formaldehyde has the chemical elements
carbon, hydrogen and oxygen in its
structure. Hydrocarbons are among the
most common of chemical compositions.
Formaldehyde is usually sold as an aqueous
or watery solution called formalin, which
contains 37 to 50 percent formaldehyde by
weight. It is soluble in water, but not in most
organic solvents, except alcohol and ether.

46. Fumigation
• To sterilize the operation theatre
formaldehyde gas (bactericidal &
sporicidal,viricidal) is widely employed as it is
cheaper for sterilization of huge areas like
operation theatres. Formaldehyde kills the
microbes by alkylating the amino acids and
sulfydral group of proteins and purine bases.
• In spite of the gas being hazardous continues
to be used in several developing countreis
Dr.T.V.Rao MD 46

47. Procedure of Fumigation
• Thoroughly clean windows, doors, floor,
walls and all washable equipment's with
soap and water.
• Close windows and ventilators tightly. If
any openings found seal it with
cellophane tape or other material.
• Switch off all lights, A/C and other
electrical & electronic items
• Calculate the room size in cubic feet
(L×B×H) and calculate the required
amount of formaldehyde as given inDr.T.V.Rao MD 47

48. Personal care during fumigation
• Adequate care must be taken by wearing
cap, mask, foot cover, spectacle .,
• Formaldehyde is irritant to eye & nose;
and it has been recognized as a potential
carcinogen.
• So the fumigating employee must be
provided with the personal protective
equipment's.
Dr.T.V.Rao MD 48

49. Creating the Formaldehyde gas
• Electric Boiler Fumigation Method: For Each
1000 cu.ft of the volume of the operation
theatre 500ml of formaldehyde (40% solution)
added in 1000ml of water in an electric boiler.
Switch on the boiler, leave the room and seal
the door. After 45 minutes (variable
depending to volume present in the boils
apparatus) switch off the boiler without
entering in to the room .
Dr.T.V.Rao MD 49

50. Methods on Fumigation
• In principle we have to
generate Formaldehyde gas.
• Can be done by
Most easier way to mix the
needed quantity of
Formalin to water and
heating at lower
temperatures at 800c –
900c
Can done also with addition of
Formalin to potassium
permanganate
Dr.T.V.Rao MD 50

51. Adding Potassium Permanganate to
formaldehyde..
• Potassium Permanganate Method: For
every 1000 cubic feet add 450gm of
Potassium permanganate (KMnO4) to 500
ml of formaldehyde (40% solution). Take
about 5 to 8 bowels (heat resistant; place it
in various locations) with equally divided
parts of formaldehyde and add equally
divided KMnO4 to each bowel. This will
cause auto boiling and generate fume.
• After the initiation of formaldehyde vapour,
immediately leave the room and seal it for at
least 48 hours.
Dr.T.V.Rao MD 51

52. Fumigation to be neutralized
• Neutralize Residual
formalin gas with
Ammonia by exposing
250 ml of Ammonia per
liter of Formaldehyde
used.
• Place the ammonia
solution in the centre of
the room and leave it
for 3 hours to neutralize
the formalin vapour
Dr.T.V.Rao MD 52

53. An example is set as..
• Operation Theatre Volume = L×B×H = 20 × 15
× 10 = 3000 cubic feet
• Formaldehyde required for fumigation = 500
ml for 1000 cubic feet
• = So 1500 ml of formaldehyde required
• Ammonia required for neutralization = 150ml
of 10% ammonia for 500 ml of formaldehyde
• = So 450 ml of 10% ammonia require
Dr.T.V.Rao MD 53

54. Need for Newer Chemical Agents in
Hospital Use
• 1. A need for Non
Aldehyde based
Chemicals is growing
concern
• 2 Need for quicker
sterilization methods
with ever increasing
work loads.
• 3. Need for non toxic
safe agents. Dr.T.V.Rao MD 54

55. Bacillocid® rasant
• Formaldehyde-free
disinfectant cleaner with
low use concentration
• very good cost/benefit
ratio
• good material
compatibility
• excellent cleaning
properties
• virtually no residue
Dr.T.V.Rao MD 55

56. Bacillocid® rasant
• Active ingredients: Glutaral 100 mg/g, benzyl-C12-
18-alkyldimethylammonium chlorides 60 mg/g,
didecyl-dimethylammonium chloride 60 mg/g.
• Bacillocid® rasant is suitable for the disinfectant
cleaning of washable surfaces using the wet-wipe-
procedure.
• Especially suitable for economic short-term
disinfection in risk areas that are likely sources of
infection
Dr.T.V.Rao MD 56

57. Newer and Non Toxic compounds.
• A Chemical compound VIRKON gaining
importance as non Aldehyde compound.
• Virkon proved to be safe
Virucidal
Bactericidal,
Fungicidal
Mycobactericidal
Dr.T.V.Rao MD 57

58. VIKRON is Finding Place in
• As a Chemical disinfectant.
• Disinfects Medical devices.
• Disinfects Laboratory equipment.
• Decontaminate spillages with Blood and
body fluids.
• Finding usefulness in replacing
autoclaving and saving time.
Dr.T.V.Rao MD 58

59. Yet no Ideal Chemical Agent
• Researchers concluded
that each prep agent has
specific advantages and
disadvantages and no one
skin prep agent is
superior in all clinical
situations. Factors to
consider when choosing a
skin prep agent include
surgeon preference and
environmental risks.
Dr.T.V.Rao MD' TMC Kollam Kerala 59

60. Gas plasma
Sterilization
Dr.T.V.Rao MD 60

61. • 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
• Can be used for hand
sterilization
What is Gas Plasma
Dr.T.V.Rao MD 61

62. 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.
Dr.T.V.Rao MD 62

63. 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 Dr.T.V.Rao MD 63

64. • 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
BASIC MECHANISMS OF PLASMA
STERILIZATION
Dr.T.V.Rao MD 64

65. 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 low-
moisture
environment not
exceeding 50ºC,
Dr.T.V.Rao MD 65

66. Waste disposal
• Clinical waste - HIGH risk
–potentially/actually contaminated waste
including body fluids and human tissue
–yellow plastic sack, tied prior to
incineration
• Household waste - LOW risk
–paper towels, packaging, dead flowers,
other waste which is not dangerously
contaminated
– black plastic sack, tied prior to incinerationDr.T.V.Rao MD' TMC Kollam Kerala 66

67. 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.
Dr.T.V.Rao MD 67

68. Han
Yet – No substitute for Hand Washing
:
Immediately on arrival at work
Before and after examining each client
After touching anything that might be
contaminated
After handling specimens
Before putting on gloves for clinical procedures
After removing gloves
After using the toilet or latrine
Before leaving work
Dr.T.V.Rao MD 68

69. Hand Hygiene Compliance
• Researchers have
implemented a hand
hygiene program driven
by a behavioral change
approach to increase
hand hygiene
compliance.. It included
access to alcohol
sanitizer, education as
well as ongoing audit
and feedback.
Dr.T.V.Rao MD' TMC Kollam Kerala 69

70. Hand Hygiene Techniques
Many Ways
1. Alcohol hand rub
2. Routine hand wash
10-15 seconds
3. Aseptic procedures
1 minute
4. Surgical wash 3-5
minutes
Dr.T.V.Rao MD' TMC Kollam Kerala 70

71. Remember we are More important than
many Chemicals
Dr.T.V.Rao MD 71

72. Soap Water and Common sense are Best
Antiseptics- William Osler
Dr.T.V.Rao MD' TMC Kollam Kerala 72

73. • Programme created by Dr.T.V.Rao
MD for Health Care Workers in
Developing World
• Email
• doctortvrao@gmail.com