This document discusses various terms related to disinfection including sterilization, disinfection, sanitization, and asepsis. It describes factors that influence the efficacy of disinfectants such as organism load, contact time, and temperature. The document outlines the properties of ideal disinfection and types of disinfectants including high, intermediate, and low level disinfectants. Various chemical and physical disinfection methods are explained along with testing methods to evaluate disinfectant efficacy.
3. INTRODCTION
•All are are
interrelated terms
aiming to destroy
or remove
microorganism but
differ in efficiency.
STERILIZATION
DISINFECTION
SANITIZATION
ASEPTIC
4. TERMS & DEFINITION
STERILIZATION
• A process by
which all the
living
microorganisms
including viable
spores ,are
either destroyed
or removed
from a article,
surface or
medium
SANITIZATION
• Refers to the
reduction in the
pathogenic
microbial
population to a
level, at which
the items are
considered as
safe without
protective
attires.
ASEPTIC
• A process where
chemical agents
called
antiseptics are
applied on body
surface, which
kill or inhibit the
microorganisms
present on the
skin.
5. DISINFECTION
Refer to a process that destroy or remove most
if not all pathogenic organism but may or may
not destroy bacterial spores.
European committee Standardisation
The section elimination of certain undesirable
organism in order to prevent their transmission,
achieved by action on their structure or metabolism,
irrespective of their functional state.
British Standard Institution
Destruction of microorganism but not usually
bacterial spores. It does not kill all the organism
but reduce it to acceptable level for a defined
purpose.
6. FACTORS INFLUENCING EFFICACY
The efficiency
of
disinfectants
is affected by
various factor
Organism load
Contact time
Nature of organism
Concentration
Temperature
Local pH
Organic matter
Biofilm
7. PROPERTIES OF IDEAL DISINFECTION
Broad
microbial
activity
Fast acting
Not affected
by organic
matter
Non-toxic
Compactable
with the
surface
Order less or
Pleasant
order
Economical
13. MOA: They combine with nucleic acid, proteins and inactivate
them by cross linking & alkylating the molecules.
Glutaraldehyde
Have to be activated before use.
Once activated, remains active for 14 days.
Used for semi critical equipment,
Fogging
Cleaning of floor & surfaces of critical areas.
Advantage
• Active in the presence of
organic matter
• Non-corrosive to
equipment.
Disadvantage
• Pungent odour
• Eye irritation
• Contact dermatitis.
ALDEHYDE
14. Ortho-phtharlaldehyde
Advantage
• Does not require
activation,
• Better odour
• less eye irritation,
• acts faster (5-10 min)
Disadvantage
• Does not kill spores
effectively
• Stain skin grey.
Available in 0.55%,
Used for disinfection of semi critical items.
15. Formaldehyde
• Excellent HLD but for health care issue it
is only restricted to non-patient care.
• Used for preservation of anatomical
specimen and stool specimen.
• Fumigation of closed area done.
(obsoleted practice)
16. PERACETIC ACID
Mostly use in automated
machines.
0.1-0.2%
Manual immersion
5 -15min
instruments sterilization
Advantage
Combination with hydrogen peroxide used for disinfecting
hemodialyzers.
Disadvantage
Expensive
Material compatibility issues
Irritation
17. HYDROGEN PEROXIDE
Works by producing destructive hydroxyl free radicals that can attack
various cell components.
•3%
•Surface disinfection
•Wound cleaning
•3-6%
•Disinfect soft contact lens,
tonometer biprisms, ventilators,
fabrics, endoscopes, etc.
•>4-5%
•Sporicidal
•6-7.5%
•Plasma sterilization
Vaporized from is used for industrial
sterilization
18. • Active in presence of organic
material
• Rapid in action
• Nontoxic
• Good cleaning ability
Advantage
• Expensive
• Contraindicated for use on
copper brass, zinc, aluminium
• Chemical irritation
• Have to stored in dark
containers.
Disadvantage
20. ALCOHOL
• Act by denaturation of proteins
MOA
• Bactericidal, Fungicidal
• 70% used as skin antiseptic
Advantage
• Not Sporicidal
• Inactivated by organic matter
• Flammable
• Evaporate rapidly
Disadvantages
21. PHENOLICS
Disadvantages
Causes hyperbilirubinemia in infants.
Advantages
Only ILD which is active in presences of organic matter
Use
Cresol & Lysol used as disinfectants. 5% phenol is mycobactericidal Chloroxylenol use as antiseptic
MOA
Phenol / carbolic acid was first introduced as antiseptic and
disinfectant for surgery by Joseph Lister.
Phenolics act as protoplasmic poison, disrupt the cell wall and precipitate the cell proteins
.
28. CHLORHEXIDINE GLUCONATE
CHG Is a biguanide disinfectant, acts by
disruption of cytoplasmic membrane.
Uses
• Mouthwash (0.1-
0.2%)
• Hand rub (0.5%)
• Skin disinfectant
(2%)
• Hand wash (4%)
Advantages
• Prolonged action
than alcohol.
• Less irritant.
Disadvantages
• pH dependent
• Reduce in
organic matter
• Dermatitis on
prolonged use.
Savlon (Combination of CHG 0.3%, cetrimide & isopropyl alcohol)
29. QUATERNARY AMMONIUM COMPOUND
Positively charged quaternary nitrogen
(+)
Long hydrophobic aliphatic chain
MOA
Disruption the cell
membrane &
denature the
proteins.
Use
Sanitation of
noncritical surfaces
& medical
equipment
Example
• Benzyl ammonium
chloride(does not
act in hard water)
• Didecyl dimethyl
ammonium
bromide (Active in
hard water)
32. CLEANING METHOD
Manual Cleaning
Immersion the instrument or wipe the surface with
cleaning agents.
Automatic or Mechanical Cleaning
Cleans faster with higher standard
Hard to reach parts of instrument.
Eg:- Ultrasonic washer
Washer disinfector
Automated cart washer
36. DISINFECTION OF ENVIRONMENT
ORDER
• Cleaning with a cleaning agent is performed first,
before applying disinfectant
• CDC recommends to use ILD to LLD for
environmental disinfection.
SEQUENCE
• Cleaner to dirtier area
• Higher to lower
• Inward to outwards
37. FREQUENCY OF CLEANING DEPENDS ON
• Probability of contamination
• Vulnerability of population to infection
• Frequency of hand contact
COMMON SITUATIONS
• Non-critical surfaces: 2-3 times a day
• Mattress: weekly or after discharge
• Doors, windows, walls, ceiling: once a month or
soiled
• High touch area: every 3-4 hours.
39. DISINFECTION OF OPERATION THEATRE
Cleaning followed by disinfection by aldehyde based
disinfectants
FREQUENCY
• First cleaning of the day
before the case
• Between cases(cleaning 3 to
4 feet perimeter around the
OT table)
• Terminal cleaning of OT
after the last case.
• Detailed wash-down of the
OT complex once a week
40. •25ml 40%
Formaldehyde
heating dish.
Seal with
adhesive
tape
•Vaporize the
formaldehyde
& leave it over
night.
•Following day
expel the air
through HEPA
filter
•Open the
front closer
1cm for
increase air
flow, when all
vapours are
removed,
remove the
seal and check
the air flow
DISINFECTION OF SAFTY CABINATE
49. PHENOL COEFFICIENT (RIDEAL WALKER) TEST
Highest dilution of the test disinfectant that kills S. Typhi in a given time
Highest dilution of phenol that kills S. Typhi in the same time
If >1, the test disinfectant is said to be more effective than
phenol
DRAWBACKS
1) only the phenolic compounds can be assessed
2) it does not assess the ability of the disinfectant to act in
presence of organic matter.
50. CHICK MARTIN TEST
• It is a modification of Rideal and Walker test
• Asses the ability in presence of organic matter
CAPACITY (KELSEY-SYKES) TEST
• It tests the capacity of a disinfectant to retain its activity
when the microbiological load keeps increasing.
• Used to test efficacy of new disinfectant (which dilutions
are suitable for use)
51. IN-USE (KELSEY-MAURER) TEST
• It simulates real-time situation.
• It is used to determine whether an in-use solution of
disinfectant in hospital is microbiologically contaminated.
