The document discusses various methods of asepsis, sterilization, and disinfection. It defines key terms like cleaning, asepsis, antiseptic, disinfectant, sterilization, and sanitizing. It describes different sterilization methods including physical methods like heat, filtration, and radiation as well as chemical methods using alcohols, aldehydes, and other agents. It provides details on specific sterilization techniques and the mechanisms by which they kill microorganisms.

1. ASEPSIS
& STERILIZATION
Dr.RAJA RATNAKAR ADDALA
1ST YEAR PG

2. DEFINITIONS
 CLEANING :
- It is a process which removes visible contamination
but does not necessarily destroy micro organisms .
- It is necessary prerequisite for effective disinfection
or sterilization. eg : water, soap or detergent, ammonia
etc.
 ASEPSIS :
- It is used to describe methods which prevent
contamination of wounds and other sites, by ensuring
that only sterile objects and fluids come into contact
with them.

3. DEFINITIONS
 ANTISEPTIC :
- chemical agent applied to living tissue such as skin or
mucous membrane to reduce the micro organisms present
,through inhibition of their activity by destruction.
eg: iodine, phenol, alcohol, hydrogen peroxide, chlorhexidine
gluconate etc . (Patterson, 1932)
 DISINFECTANT :
- chemical used on non vital objects which kills the viable
micro organisms to an acceptable level but may not inactive
all the viruses, bacterial spores.
eg: sanitizers used in hospitals, oxidizing agents, phenolics,
aldehydes etc . (Patterson, 1932)

4. DEFINITIONS
 STERILIZATION :
- It is the process of destruction or removal of all
micro-organisms from article, surface or medium,
including spores. (Patterson,1932)
 SANITIZING :
- It is the process that reduces microbial population
on an object to a safe level.
 DECONTAMINATION :
- It is the process that removes pathogenic micro-
organisms from an object to make it safe to handle.

5.  Bactericidal Agents / Germicides :
- Chlorine preparations
- Iodine ( povidoneiodine)
- Alcohols
- Phenolics
- Chlorhexidine
 Bacteriostatic Agents :
- Disinfectants
- Antiseptics
- Preservatives

6. PRESTERILIZATION
CLEANING
 OBJECTIVE :
- Removal of organic matter, blood and saliva
which hosts for micro-organisms.
• Three Methods of CLEANING :
- Manual
- Mechanical
- Ultrasonic

7.  MANUAL CLEANING :
- Simple & Cheapest Method.
- time consuming & difficult to achieve.
- One pre requisite is that heavy duty gloves and
glasses must be worn to protect needle stick injury
and to protect eye.
- Material used for manual cleaning
1.Soaps
2.detergents

8.  ULTRASONIC CLEANING :
- Principle - conversion of electrical energy into
vibratory sound waves which pass through a soap
solution containing the instrument.
- Used mainly for burs, bone files, bone cutter,
artery forceps, saw etc.

9.  MECHANICAL WASHING :
- Principle - Squirting of high-pressure jets of
water with or with out a detergent which removes
debris from instrument.
- Small instrument like burs, blades are not
suitable for this type of cleaning.

10. THERMAL DEATH TIME
 DEFINITION :
- Minimum time required to kill a suspension
(specified) of organisms at a predetermined
temperature in a specified environment.
- TDT is inversely proportional to temperature.
- TDT is increased in presence of organic substance,
proteins, nucleic acid, starch, gelatin, sugar, fats,
oils.

11. STERILIZATION
 Why we need STERILIZATION ??
Micro-organisms
- capable of causing infection.
- responsible for contamination and infection.
 The Aim of sterilization :
- to remove or destroy them from materials or
from surfaces.
 The instruments :
- should be thoroughly packed and sterilised
before use, to prevent contamination and infection.

13. AGENTS USED IN STERILIZATION
PHYSICALAGENTS
SUNLIGHT
DRYING
HEAT
FILTRATION
RADIATION
CHEMICALAGENTS
ALCOHOLS
ALDEHYDES
DYES
HALLOGENS
PHENOLS
SURFACE ACTIVE AGENTS
METALLIC SALTS
GASES

14. PHYSICAL AGENTS
 SUNLIGHT :
- Natural method of sterilization
- Active Germicidal Property
- Uv rays & Heat rays
- Semple & Grieg showed in INDIA that,
thyphoid bacilli exposed to sun on pieces of
white drill cloth were killed in two hours,
whereas controls kept in the dark were still alive
after six days .
- Bacteria suspended in water are readily
destroyed by exposure to sunlight.

16.  DRYING :
- Moisture is essential for bacterial growth.
- 4/5th of the wt. Of bacterial cell is due to water.
- Deleterious effect on many bacteria.
- Unreliable & Uneffective to spores.

17. HEAT
DRY HEAT
RED HEAT
FLAMING
INCINERATION
HOT AIR OVEN
MOIST HEAT
TEMPERATURE :
BELOW 100 °C
AT 100°C
ABOVE 100°C
(AUTOCLAVE)

18. Mechanism of Action
DRY HEAT
o Protein denaturation.
o Oxidative damage.
o Toxic effects by
increased levels of
electrolytes.
MOIST HEAT
o Protein denaturation &
coagulation.
o Latent heat liberated
when steam condenses
on cooler surface.
o Hydrolysis &
breakdown of bacterial
proteins.

19. DRY HEAT
RED HEAT
 Inoculating
Wires or loops,
Tips of forceps,
Needles.
 Held in the flame of Bunsen
burner till they become red
hot .
FLAMING
 Glass slides,
Scalpels,
Mouth of culture tubes.
 Passed through Bunsen
burner flame without
allowing them to become
red hot.

21.  INCINERATION :
- Instrument – Incinerator
- Infective materials are burnt into ash.
- Temperature : 8700C - 9800C
- Items: contaminated cloth, animal carcasses and
pathological material.
- Plastics : PVC, polythene can be dealt.
-However, polystyrene will emit black smoke.
- Hence should be autoclaved in appropriate
container.

23.  HOT AIR OVEN :
- Holding Temperature : 160°c for 45mins
170°c for 18mins
180°c for 7.5mins
190°c for 1.5mins
- Items:
1.Glass ware : glass syringes, petridishes,
flasks, pipettes, & test tubes.
2.Surgical instruments : Scalpels, scissors,
forceps etc.
3.Chemicals : Paraffin, fats, etc.

24.  Precautions :
 Materials should be properly arranged to allow free
circulation of air.
 Don’t over load the oven.
 Before placing in hot air oven :
1.Dry glassware completely.
2.Plug test tubes with cotton wool.
3.Wrap glassware in Kraft papers.
 Advantage :
- Maintenance of the sharp edges of the cutting
instruments.

25.  STERILIZATION CONTROL :
-To check whether the equipment is working properly.
• Chemical controls : Browne’s tubes
Color change from red to green
• Thermocouples
• Biological controls : paper strips containing 106 spores of
Clostridium tetani.
oPlace strips in oven along with other material for the
sterilization .
oLater culture the strips in thioglycollate broth or CMM
at 370C for 5 days .
oGrowth in medium indicates failure of sterilization .

27.  GLASS BEAD STERILIZATION :
- Uses small glass beads (1.2- 1.5
mm diameter ) and high
temperature – (210°c – 230°c ) for
10-30 seconds to inactive micro-
organisms.
- Endodontic files, burs

28. MOIST HEAT
 DIFFERENT TEMPERATURE USED FOR STERILIZATION :
- Temperature below 100°c
- Temperature at 100°c
- Temperature above 100°c

29. o 1. Temperature below 100°c :
• Pasteurization
• 630C – 30 min (Holder method) –all non-sporing pathogens
are destroyed. eg: mycobacterium, brucellae ,salmonellae.
• Coxicella burnetti – may survive in the holder method.
• 720C – 15-20 sec (Flash method).
• Vaccine baths : 600C – 60 min
• For vaccines of non- sporing bacteria.
• Water bath : 560C – 60 min – several successive days.
• For serum / body fluids containing coagulable proteins.
• Inspissation : 80- 850C – 30 min – 3 successive days.
• For media containing egg or serum – Lowenstein Jenson,
Loeffler’s serum .
• Instrument – inspissator.

30. o Temperature at 100°c :
• Boiling : 90°c -100°c
- kills all vegetative bacteria
- It may not kill the all spore bacteria,
but may kills hepatitis virus, & some
spore
-Water should be soft, de ionized or
distilled.
-2% sodium bicarbonate promotes
the process.
- Not recommended for sterilizing of
instruments used for surgical
procedures.

31. • Tyndallisation :
- Steam – 100°c -20min on 3 successive days
- Also called Intermittent sterilization.
- Kills vegetative bacteria first, then the remaining
spores killed on subsequent heating.
- sterilise – egg, serum, or sugar contaning media.
• Steam sterilizer : (Koch’s/Arnold’s steriliser)
- 100°c – 90 min
- articles are kept on a perforated tray through
which steam can be passed.

32. o Temperature above 100°c :
 Several types of steam steriliser are in use:
-Laboratory autoclaves, hospital dressing
sterilisers, bowl & instrument steriliser, rapid
cooling sterilisers.
-Domestic pressure cooker can also be used.
o Flash Sterilisation :
- 134 °c 29.4psi 3mins
-used in operating room where fast
sterilization of instruments may be necessary.

34. o AUTOCLAVE (Steam under pressure) :
- Holding Temperature : 121°c for 15mins
126°c for 10mins
(15 lbs or psi pressure)
- Culture media, rubber material, gowns, dressings,
gloves, instruments and pharmaceutical products
-Useful for materials which cannot withstand the
high temperature of hot air oven

36. TYPES OF AUTOCLAVE
International Journal of Biological & Medical
Research Int J Biol Med Res. 2011; 2(1): 472-486
o Three types : Gravity type, Pre-vacuum type & Retort type.
• Gravity type: air is evacuated with the help of gravity
alone. The system operates with temperature of 121°c
steam pressure of 15 psi for 60-90 minutes.
• Vacuum pumps type : used to evacuate air from the Pre
vacuum autoclave system , so that the time cycle is reduced
to 30-60 minutes - 132°C.
• Retort type autoclaves : designed to handle much
larger volumes & operate at much higher steam temperature
and pressure .

37.  STERILISATION CONTROL :
-Thermocouples .
-Browne’s tube (red-green), Bowie & Dick tape
(white-Brown ) .
-106 spore of Bacillus stearo thermophilus.
Incubate at 550C for 5 days .

38.  FILTRATION :
- Removes bacteria from heat liable liquids.
- Used to sterilize serum, carbohydrates solution, antibiotics
solutions, filtrates of toxins & bacteriophages.
- Sterilize solutions that may be damaged or denatured by high
temperatures or chemical agents .
o Types of FILTERS :
1. Earthenwire filters ( Candle filters) .
2. Asbestos filters .
3. Sintered filters .
4. Membrane filters .

39.  Earthen wire filters :
- widely used for purification of water.
- 2 types : - Unglazed ceramic filters .
- Diatomaceous earth filters .
 Asbestos filters :
- disposable, single use discs.
- high adsorbing capacity .
- but carcinogenic, so discouraged their use.

41.  Sintered glass filters : prepared by fusing finely
powdered glass particles .

42.  Membrane filters :
- made of cellulose esters.
- routinely used in water purification & analyses.
- sterilisation & sterility testing.

43.  Other Filters :
- Syringe filters .
- Air filters .
• Syringe Filters :
- Syringes fitted with
membrane filters of different
pore sizes are available .
- The fluid is forced through
the the disc (membrane) by
pressing the piston of the
syringe .

44. • Air Filters :
- Air can also be sterilized by
filtration .
- Large volumes of air may be
rapidly freed from infection by
passing through high efficiency
particulate air (HEPA) filters .
- They are used in laminar air flow
system in microbiology laboratories.
- HEPA filters can remove particles
of 0.3 µm or larger .

45. HEPA ( HIGH EFFICIENCY PARTICULATE AIR)

46.  RADIATION :
• 2 types :
1. Ionising Radiation
- cold sterilisation .
- gamma rays, X-ray, & cosmic rays.
- very high penetrating power
- highly lethal to all cells including
bacteria . damage DNA by various
mechanism .
- used for sterilising disposable items
( plastic syringes, swabs, culture plates,
canulas, catheters)

47. 2. NON IONISING RADIATION :
- Infrared rays & ultraviolet rays
- Rapid mass sterilisation of syringes &
catheters.
- Wavelength 240 to 280nm –
bactericidal activity.
- Acts by denaturation of bacterial
proteins and interferes with DNA
replication.
- used in Disinfecting enclosed area
• bacteriological lab.
• Innoculation hoods .
• laminar flow .
• Operative theatres.

48. • Sterilization controls
– Dosimeter – measures radiation dose .
– Colored discs .
– M radiodurans, B pumilus .

49. CHEMICAL METHODS
 Alcohols :
- Ethanol and isopropanol are the most frequently
used .
- Skin antiseptics and act by denaturing bacterial
proteins .
- Rapidly kill bacteria including tubercle bacilli but
they have no sporicidal or virucidal activity.
- 60-70% is most effective.
- Isopropyl alcohol is preferred to ethyl alcohol as
it is a better fat solvent, more bactericidal and less
volatile.
- Methyl alcohol is effective against fungal
spores.

50.  Aldehydes :
- Formaldehyde
- Gluteraldehyde
o Formaldehyde :
- Formaldehyde is active against the aminogroup .
- lethal to bacteria and their spores, viruses and
fungi .
- employed in the liquid and vapor states .
- 10% aqueous solution is routinely used .
- Available commercially ‘Formalin’ .

51.  Uses :
-To sterilise bacterial vaccines .
- 10% formalin containing 0.5% sodium
tetraborate is used to sterilize clean metal
instruments.
-Formaldehyde gas is used for sterilizing
instruments, heat sensitive catheters and for
fumigating wards, sick rooms and laboratories.

52. o Glutaraldehyde :
- Action similar to formaldehyde .
- More active and less toxic than formaldehyde .
- It is used as 2% buffered solution .
- available commercially as ‘cidex’ .
• Uses :
-For sterilization of cystoscopes, endoscopes and
bronchoscope.
-To sterilize plastic endotracheal tubes, face masks,
corrugated rubber anaesthetic tubes and metal
instruments .

53. • FUMIGATION :
Fumigation consisted of a mixture of formalin (280
ml) and potassium permanganate (150 gm) being
placed in a bowl. The room would then be sealed
& opened 12-24 hours later.

54. o Different Methods
1. Carboxyl acid & fumigation with Formaldehyde
Advantages – Established age old technique
Cost effective
Disadvantages –
a. Time consuming, min 24 hrs turn
around time
b. Self defeating – OT fumigated with
Formaldehyde needs to be de-aired
with unclean air
c. Unsafe Formaldehyde is carcinogenic

55. 2) Aldehyde based germicides
Glutaraldehyde & formaldehyde (200 ml in 10 liters of
water i.e 2%) through fogging machine is the
commonly used procedure.
Advantages- Effective
Disadvantages – a. Leaves sticky residue because of
surfactant base
b. Self defeating – OT fumigated
with Formaldehyde needs to be
force de-aired with unclean air
c.Unsafe- Formaldehyde has been
identified as a carcinogen

56. 3. Silver (Ag) and Hydrogen Peroxide (H2O2)
Advantages – a. Has deep penetrating capability
b. Has no known resistant strains
c. Effective against
Bacteria,Viruses,
Mycobacteria, Amoeba, Fungi
spore forming organisms

57.  DYES :
• 2 groups of dyes:
– Aniline dye
– Acridine dye
• Bacteriostatic
• Aniline dye:
Used in microbiology labs as selective agents in culture
media.
• Acridine dye is non- selective & impair the DNA complexs of
organisms thus kills or destroy the reproductive capacity.
skin and wound antiseptics eg: proflavine, acriflavine .

58.  HALLOGENS :
• Iodine
– Skin disinfectant .
– Active bactericidal, moderate action on spores.
– Betadine is most commonly used .
• Chlorine
– Water supplies, swimming pools and food and dairy
industries.
– Along with hypochlorides are bactericidal. Also act
on viruses.
– Sodium hypochlorite Most widely disinfectent for
HIV.

59.  Phenols :
- Obtained from distillation of coal tar between
170-270°C.
- Lethal effect:
Capacity to cause cell membrane damage,
releasing cell contents and causing lysis.
- Low concentration will precipitate proteins.
o Cresols
- Lysol is a solution of cresols in soap
- Most commonly used for sterilization of infected
glasswares,cleaning floors.

60.  Gases :
• Types of Gases :
1. Ethylene Oxide
2. Formaldehyde Gas
3. Beta Propiolactone (BPL)
o Ethylene Oxide : (ETO)
• Action is due to alkylating the protein molecules and
also on DNA and RNA.
• Items : Heart-lung machienes, respirators, sutures, dental
equipment, books, clothing.

61. o Formaldehyde Gas :
- Employed for fumigation of OT and other rooms.
- After fumigation, the doors should be sealed and
left unopened for 24-48hrs.
o BPL (Beta Propiolactone ) :
- Product of ketane and formaldehyde with a
boiling point of 163°C.
- Rapid biocidal activity but carcinogenic.
-Capable of killing all microorganisms and is very
active against viruses.

62.  Surface Active Agents:
- Act as detergents and emulsifiers.
- Sodium lauryl sulphate effective against streptococcus
pneumonia.
 Salts of heavy metals :
- Have a greater action. Eg: salts of silver, copper
and mercury.
- Act by Protein coagulantion .

63. STERILIZATION AND DISINFECTION IN
DENTAL UNIT
- DENTAL INSTRUMENTS
- DENTAL UNIT AND ENVIRONMENTAL
SURFACES
- DENTAL LABORATORY

64. DENTAL INSTRUMENTS
CLASSIFICATION BASED ON :
RISK OF TRANSMISSION AND NEED OF
STERILIZATION :
-CRITICAL
-SEMI-CRITICAL
-NON-CRITICAL

65.  Critical Instruments :
- Penetrates mucous membrane or contact bone,
blood stream, or other normal sterile tissues.
- Heat Sterilization should be done between uses
or sterile single-use or disposable devises should be
used.
- Eg : Surgical instruments, scalpel blades,
periodontal scalers, & surgical dental burs.

66.  Semi Critical Instruments :
- Contact Mucous membrane, but do not penetrate
soft tissue .
- Heat Sterilize or High Level Disinfect .
- Eg : Dental Mouth mirrors
Dental Handpieces.

67. Non- Critical Instruments :
- Contact intact skin
- Clean and Disinfect using a low to intermediate
disinfectant.
- Eg : X-rays, Pulse Oximeter, Blood pressure cuff.

68.  Dental Unit :
- Cleaned by DISPOSABLE TOWELING
EPA- Environmental Protective Agency
use EPA registered hospital disinfectant.
- Cleaning Agents Like
Phenolics, iodophors, chlorine containg
compounds.

69.  Environmental Surfaces :
o CLINICAL CONTACT SURFACE :
-High potential for Direct
Contamination from spray or spatter
or by contact with glove hand.
o HOUSEKEEPING SURFACES :
- Do not come into contact with
patients or devices .
- Limited Risk of disease
transmission.

70.  CLEANING CLINICAL CONTACT SURFACE :
- Risk of transmitting infections greater than for house
keeping surfaces
- Surface barriers can be used and changed between
patients
 CLEANING HOUSEKEEPING SURFACES :
- Routinely cleanup with Soap & Water or an EPA-
Registered Detergent/ Hospital Disinfectant.
- Clean MOPS & CLOTHS and allow to dry thoroughly
before re-use.
- Prepare Fresh Cleaning and Disinfecting Solutions
daily and per manufacturer recommendations.

71. HISTORY
Father of Antiseptic surgery – Dr. JOSEPH LISTER
(1827-1912) first studied prevention of wound
infection during an operation (1865-1891) inspired
by LOUIS PASTEUR ‘s of the germ theory of disease .
Discovered the effectiveness of 'carbolic acid’
(phenol).

72. SURGICAL ASEPSIS
Surgical asepsis differs from medical asepsis.
Medical asepsis is defined as any practice that helps
reduce the number and spread of microorganisms.
Surgical asepsis is defined as the complete removal
of microorganisms and their spores from the
surface of an object .
The practice of surgical asepsis begins with cleaning
the object in question using the principles of
medical asepsis followed by a sterilization process.

73.  Which Procedures Require Surgical Aseptic
Technique:
- Any medical procedure that involves penetration
of body tissues. (invasive Procedure)
- Major & Minor surgeries
- Tracheotomy care
- Catheterization of the urinary bladder.

74.  The Environment and Surgical Asepsis
• Creating an environment in a surgical suite or special
procedure room, to avoid any possible infection to the
patient.
• Proper attire (scrubs, cap, mask, gloves, shoe covers)
• Awareness!!!!

75. Why ,Who, and What ? ? ?
 Why is infection control necessary in dentistry ?
Dental staff and patients may be exposed to a wide variety of
pathogenic microorganisms .
 Who is responsible for infection control in the dental office ?
Each member of the dental team must follow the recommended
guidelines .
 What should be done to prevent the transmission of disease in the
dental office ?
The most effective ways to prevent the transmission of diseases
includes :
1) Hand washing
2) Gloves
3) Face masks
4) Protective eye wear
5) protective clothing
6) instrument sterilization and disinfection

76. STANDARD PRECAUTIONS
 IMMUNIZATION
 PATIENT SCREENING
 HAND WASHING
 BARRIER TECHNIQUES -
• Personal Protective Equipment (PPE)
• Rubber dam, Pre-procedural rinsing
 NEEDLE & SHARP INSTRUMENT SAFETY
• Occupational Exposure To Blood/Body Fluids
 SURFACE DISINFECTION
 RADIOGRAPHIC ASEPSIS
 LABORATORY ASEPSIS
 INFECTIOUS DENTAL WASTE MANAGEMENT & DISPOSAL

78. OSHA PROTOCOLS
 Shoes must be comfortable with closed heel and toe but
should not be covered with cloth. Cloth-covered shoes may
allow blood, body fluids, and other liquids to permeate.
Cloth-covered shoes will not protect the feet from a heavy
object fall on them.
 So shoe covers must be placed over shoes to reduce
contamination and to protect shoes from coming in contact
with blood and body fluids.
 Personal hygiene must be meticulous. A shower should be
taken shortly before beginning a work day in the operating
room or special procedure area.
 Jewelry, long or artificial fingernails, and nail polish are
prohibited. Jewelry harbors microorganisms . Any body
piercing jewelry must be removed as it may become loose
and fall onto the sterile field

79.  All persons who expect to proceed from the unrestricted
zone into the semi-restricted zone must go to the dressing
area, don a scrub suit, and tuck the blouse of the suit into
the pants or wear a scrub blouse that fits close to the body.
 All hair, beards, or mustaches must be covered with a
surgical cap and mask. Hair must be confined as it sheds
microorganisms with movement.
 Before proceeding into Zone 3, all persons must scrub hands
and arms for medical asepsis. It is believed that bare skin
may shed microorganisms. In many institutions, all who are
not scrubbed for the surgical procedure must wear a scrub
jacket to cover bare arms.
 Before entering a room where a surgical procedure is in
progress, a mask must be donned. The masks worn in the OR
must be single, high-filtration masks

80. ASEPTIC ZONES
 Zone 1: An unrestricted zone:
- persons may enter in street clothing.
 Zone 2 : A semi-restricted zone:
-only persons dressed in scrub dress with hair
covered and shoes covered may enter.
 Zone 3: A restricted zone:
-only persons wearing scrub dress, shoe covers, and
masks are allowed to be present. If a surgical procedure is in
progress, the doors to this area are kept closed, and only
persons directly involved in the procedure may be present.
Those directly involved in the operation are dressed in sterile
gowns and sterile gloves. They are often referred to as
“being scrubbed.”

81. PERSONAL PROTECTIVE
EQUIPMENT (PPE)
 OSHA requires the employer to provide employees
with appropriate personal protective equipment .
Examples of PPE :
1. Protective clothing
2. Surgical masks
3. Face shields
4. Protective eyewear
5. Disposable patient treatment gloves , and
6. Heavy-duty utility gloves .

82. o PROTECTIVE CLOTHING :
- Purpose : to protect the skin and underclothing
from the exposure to saliva , blood , aerosol , and
other contaminated materials .
• Types:
1) LABORATORY COATS

84. 2) GOWN
3) SURGICAL SCRUB

85. o PROTECTIVE MASKS :
-Purpose: the mask worn over the nose and mouth to
protect the person from inhaling infectious organisms
spread by the aerosol spray of the handpiece or air-
water syringe .
• Types
1) FLAT TYPE
2) DOME SHAPED

86. PRINCIPLES OF ASEPTIC
TECHNIQUE
 1. Only sterile items are used within the sterile
field.
 2. Sterile persons are gowned and gloved.
 3. Tables are sterile only at table level.
 4. Sterile persons touch only sterile items or areas.
 5. Unsterile persons avoid reaching over the sterile
field.
 6. The edges of anything that encloses sterile
contents are considered unsterile.

87.  7. The sterile field is created as close as possible
to the time of use.
 8. Sterile areas are continuously kept in view.
 9. Sterile persons keep well within the sterile area.
 10.Sterile persons keep contact with sterile areas to
a minimum.
 11. Destruction of the integrity of microbial barriers
results in contamination.

88. o Setting Up An Unsterile Table As A Sterile Field :
- The scrub person drapes an unsterile table to protect the
gown.
- Gloved hands are protected by cuffing a drape over them.
- The scrub person stands back from the unsterile table
when draping it, in order avoid leaning over an unsterile
are.

89.  The six golden rules to improve compliance in hand
hygiene given by G. Kamp:
• Rule 1. - Select an alcohol-based hand rub which has a
good skin tolerance and is acceptable to health care
workers to use .
• Rule 2. The hand rub shall be easily available.
Wall dispensers near the patient and pocket bottles may
well help .
• Rule 3. Implement teaching and promotion of
hand hygiene which has been shown to be very effective.
This may be the most effective tool but will cost time and
money .

90. • Rule 4. Create a hospital budget which covers
all costs involved with preventable nosocomial
infection
• Rule 5. Get the senior staff to set a good example in
order to motivate junior staff because negligence in
hand hygiene seems to correlate with the number
of professional years .
• Rule 6. Have the patient & staff ratio well balanced.
It has been shown that staff shortage decreases
hand hygiene compliance .

92. OT SCRUB

93. o The Surgical Scrub :
 DEFINITION :
- The surgical scrub is the process of removing as
many micro-organisms as possible from the hands
and arms by mechanical washing and chemical
antisepsis before participating in a surgical
procedure.
- skin is never sterile.

94. • Various scrub solutions :
- Chlorhexidine Gluconate
- Para-chloro-meta-xylenol (PCMX) or
chloroxylenol
- Hexachlorophene (HCP)
- Triclosan

95. • Gowning and Gloving
Techniques
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97. Infectious Medical Waste

99. • BIO MEDICAL WASTE
DEFINITION :
“any solid, fluid or liquid waste, including its
container and any intermediate product, which is
generated during the diagnosis, treatment or
immunization of human beings or animals, or in the
production or testing of biologicals and the animal
waste from slaughter houses or any other like
establishments”.

100.  Hazards from infectious waste and sharps-
-Pathogens in infectious waste may enter the
human body through a puncture, abrasion or cut in
the skin, through mucous membrane by inhalation
or ingestion.

101. • As per WHO, the biomedical wastes could be
classified into eight categories on the basis of the
type of waste and the risk of transmission of
infectious material in them :
1. General waste (domestic)
2. Pathological
3. Radioactive
4. Chemical
5. Infectious
6. Pharmaceutical wastes
7. Sharps and
8. Pressurised containers.

102. Human Anatomical Wastes
Animal Anatomical Wastes
- CAT - 3 Microbiology and Biotechnology wastes
- CAT- 4 Waste Sharps
- CAT -5 Discarded medicines and Cytotoxic drugs

103. Cat- 6 Soiled wastes include items contaminated
with blood, body fluids such as cotton,
dressings, linen, beddings etc.
Cat- 7 Solid wastes i.e. waste generated from
disposable items other than sharps such as
tubing, catheters, IV sets.
Cat- 8 Liquid wastes ( washing, cleaning )
Cat- 9 Incineration ash
Cat- 10 Chemical wastes ( disinfectants, insecticides

107. REFERENCES
 DANIEL M. LASKIN – VOLUME 1
 ANANTHANARAYANA
 DAVID GREEN WOOD- MEDICAL MICROBIOLOGY.