1. DISINFECTANTS

2. Sterlization Disinfection
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.

3. Properties of good antiseptic/ disinfectant
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/
Chemically stable and cheap

4. 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

5. Classification Phenol derivatives: Alcohols: Ethanol, isopropanol
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

6. Phenol Earliest used, reference standard Protoplasmic poison, MOA:
injures tissues & cells at high conc causes skin burn
MOA:
denaturating bacterial protiens.
USES :
To disinfect urine, faeces, pus, burns.
Extremely irritating, corrosive
Static in 0.2 & cidal in >1% conc
Accidental poisoning: rapidly absorbed penetrate intact skin, GIT corossion pain, collapse, decreased body temperature, convulsions and death by respiratory failure. Not used as antiseptoc due to corrosive nature

7. 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.
Wider margin of safety

8. Chloroxylenol (Dettol)
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%
0.8% skin cream and soap, 1.4% for mouth wash
These preparations loose activity if diluted or kept in water for long period of time
Loose activity if diluted in water and kept for long time

9. Hexachlorophene Commonly incorporated in soap
Effectively only against Gm+ve
Slow but persistant action
>2% preparations banned
Around 1970 fatalities in US due to

10. 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
includes
k permanganate, H2O2 , benzoyl perxide.
Except atropine and cocaine which are not efficiently oxidized

11. Oxidizing agents Hydrogen Peroxide Benzoyl 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
Liberates nascent oxygen which oxidizes necrotic matter and bacteria 30 % solution produces 10 volumes of oxygen much of which escapes in molecular form
Catalase present in tissue speeds decomposition resulting in faomoing and helps loosening and removing slough
Benzoyl peroxide: induces desquamation, the comedones are shed & irritant fatty acids are reduced. Mild irritant, burning sensation is often felt .

12. Halogens
Iodine,
Iodophores,
Chlorine,
Chlorophores

13. Iodine Rapidly acting broad spectrum (bacteria, fungi,virus)
Acts by iodinating and oxidizing microbial protoplasm.
Used for cuts, degerming skin before surgery.
Adverse effect: cause burns & blisters

14. 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.

15. Chlorine
potent germicide. Kills pathogens in 30 sec. used to disinfect urban water supplies.
0.1 to 0.25 ppm

16. 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
Compounds that slowly release hypochorous acid

17. 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 % oral rinse or % tooth paste
Prevention of gingivitis
How ever it may leave unpleasant taste and on repeated administration may cause brownish discoloration of teeth

18. 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)
Many gram negative bacteria like pseudomonas, mycobcaterium TB and spores are eresistant
Soaps are anionic and neutralize their action while alcohol potentiates it, spread through oil and grease and cleansing properties

19. 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
Can be medivcated by adding other antiseptics

20. 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.
Rapidity of action increases upto 70% and decreases above 90%
Cotton swab soaked in 70% alcohol rubbed on skin kill 90% of bacteria in 2 min has been used before hypodermic injection

21. Aldehydes (Formaldehyde)
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
Diluted to 4 % and is used for hardening tissues
Eczematoid reactions can reactions can occur

22. Acids Boric acid weak antiseptic , bacteriostatic.
used for mouth wash, irrigation eyes, glossitis.
Adverse effect: vomiting ,abdominal pain on systemic absorption.
10% ointment borocide is available for cuts and abrasion
Acetic acid is relatively weak antiseptic only above 5% pseudomonas is susceptible . It is occasionally used for sub burn dressing and for douche in 1-3 % strength s

23. 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.
mercuric compounds
- poor antiseptic & bacteria spore survive after contact. Not used

24. Dyes Gentian violet: Acriflavine
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
Triple dye lotion contains gentian violet brilliant green and acriflavine
TRIPLE DYE LOTION: Contain gentian violet + brilliant green + Acriflavin used for burns & dressing umblical stump in neonates

25. Ectoparasiticides
These are drugs used to kill parasites that live on body surfaces
lice → cause pediculosis (hair infection)
mites → cause scabies(skin infection)

26. Drugs used are
(1) PERMETHRIN (2) LINDANE (3) BENZYL BENZOATE (4) IVERMECTIN (5) CROTAMITON (6) SULFUR

27. 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 hrs.
Head louse: massage about 30 g in to scalp and wash after 10 min.

28. 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.
Maximum 92 % cure rate

29. 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.
For pediculosis it should be applied to scalp taking care not to enter the eyes and washed off after 24 hours now it is second choice drug for scabies and seldom used for pediculosis its combination with lindane is highly effective

30. Crotamiton low cure rates
Better results if applied for 5 days in children
Less irritation and toxicity
May be preferred in children as second choice

31. Ivermectin
Anti helminthic drug which has been recently found effective against scabies & pediculosis.
A single 0.2 mg /kg ( 12mg in adults) has % cure rate.
Contra indicated in children  5yrs , preganant & lactating women.

32. 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.

33. 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

34. Decontamination
Decontamination: the removal of disease-producing microorganisms to leave an item safe for further handling

35. Disinfection
Disinfection: the inactivation of disease-producing 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

36. 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.

37. Intermediate level disinfection:
Intermediate level disinfectants kill vegetative bacteria, most viruses and most fungi but not resistant bacterial spores.

38. 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.

39. Chemical Methods Disinfectants and antiseptics
Surface-active agents (surfactants)
Chemical food preservatives
Aldehydes
Gas sterilization
Oxidizing agents
[Antibiotics]

40. Disinfectants Stable Persist for long periods after application
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

41. Antiseptics Biguanides: Chlorhexidine Low toxicity
Used on skin and mucous membranes

42. Antiseptics Alcohol : protein denaturation and membrane damage
evaporate quickly
ethanol and isopropanol
[not effective if taken internally]

43. 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

44. 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.

45. 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

46. 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

47. 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

48. 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.

49. 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

50. Microbial Characteristics and Microbial Control
Figure 7.11

51. 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.

52. 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.

53. 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

54. 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.

55. 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

56. 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.

57. Alcohols
Higher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

58. 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.

59. 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

60. Soap, Water and common sense are yet the best antiseptics William Osler

61. 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

62. 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”.

63. 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

64. 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.

65. 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.

66. Hypochlorite's Most recommended in
They are included in most recommendation for decontamination of hepatitis and AIDS viruses

67. 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.

68. 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.

69. 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.

70. 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

71. 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.

72. 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.

73. 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

74. 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

75. 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

76. 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.

77. 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

78. 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

79. 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

80. 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, fluid-resistant gowns).

81. 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

82. Per acetic Acid
It is used in automated machines to chemically sterilize medical, surgical, and dental instruments (e.g., endoscopes, arthroscopes).

83. 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.

84. 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.

85. 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

86. 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

87. 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).

88. 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

89. 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.

90. 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

91. 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

92. 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.

93. 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, a

94. 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.

95. 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

96. When things go wrong Inadequate cleaning Using the wrong disinfectant
Failure to follow procedures

97. 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.

98. 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

99. 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