Sterilization and Disinfection
Background and definition
Around 350 BC Aristotle suggested to
Alexander the Great to boil his armies’
drinking water. He did, and that is one
of the reasons he is Alexander the
Great.
, Definition
Sterilization and Disinfection
Sterilization –
Freeing of an article from all microorganisms including viable spores and viruses
This is an absolute term, that implies total inactivation of all forms microbial life
Sterilization can be obtained by physical ( e.g., dry heat or moist heat ) and
chemical processes
Sterile
◦free of all forms of microbial life
, Disinfection
A process that eliminates many or all pathogenic microorganisms on inanimate
objects, particularly those liable to cause infection
◦control directed at destroying harmful microbes
◦some viable microbes may persist
Disinfection is a relative term embracing a wide range of efficacy against particular
viruses, vegetative bacteria and fungi but not usually including spores
Disinfection is usually accomplished by the use of physical procedures or liquid
chemicals.
, Antiseptics
◦Disinfectants formulated for use on skin
◦Less powerful than disinfectants
◦An antiseptic opposes sepsis or putrefaction
either by killing microorganisms or by
preventing their growth
◦They destroy transient flora but leaving
untouched the resident skin flora deep in
the skin pores and hair follicles
, Antimicrobial Definitions
Germicide – Chemical agents capable of
killing microbes, spores may survive
Sanitization
◦The term implies to reduced microbial
population and is used to describe
disinfection, generally in conjunction
with catering and food equipment
,Decontamination
◦Item that has been treated to reduce number
of disease-causing organisms
◦General term for the treatment used to make
equipment safe to handle, and includes
microbiological, chemical, radioactive and
other contamination
, Nature of the item to be
treated
⚫For disinfection and
sterilization, the instruments and
items for patient care are divided
into 3 categories based on the
degree of risk of infection
involved in the use of the items
, Selection of Control
critical items have
◦ direct contact with body tissues
◦ needles, scalpels
Semi critical items have
◦ contact with mucous membranes but do not
penetrate
◦ endoscopes, endotrachial tubes
non-critical items have
◦ contact with unbroken skin. countertops, stethoscopes
,Methods of Sterilization
Two main method
Sterilization of sterilization
Physical and
Chemical chemical
Physical method Chemical method of
method (gaseous sterilization are
process) achieved usually by
gaseous process
, Methods of sterilization
Method Concentration or Level
Physical Sterilants
Moist heat -Steam under 121° C or 132° C for various time intervals
pressure and tyndallization Tyndallization at 1000C
Dry heat 1 hr at 171° C; 2 hr at 160° C; 16 hr at 121° C
Filtration 0.22- to 0.45-μm pore size; HEPA filters
Ultraviolet radiation Variable exposure to 254-nm wavelength
Ionizing radiation Variable exposure to microwave or gamma radiation
Gas Vapor Sterilants
Ethylene oxide 450-1200 mg/L at 29° to 65° C for 2-5 hr
Formaldehyde vapor 2%-5% at 60° to 80° C
Hydrogen peroxide vapor 30% at 55° to 60° C
Plasma gas Highly ionized hydrogen peroxide gas
Chemical Sterilants
Peracetic acid 0.2%
Glutaraldehyde 2%
Background and definition
Around 350 BC Aristotle suggested to
Alexander the Great to boil his armies’
drinking water. He did, and that is one
of the reasons he is Alexander the
Great.
, Definition
Sterilization and Disinfection
Sterilization –
Freeing of an article from all microorganisms including viable spores and viruses
This is an absolute term, that implies total inactivation of all forms microbial life
Sterilization can be obtained by physical ( e.g., dry heat or moist heat ) and
chemical processes
Sterile
◦free of all forms of microbial life
, Disinfection
A process that eliminates many or all pathogenic microorganisms on inanimate
objects, particularly those liable to cause infection
◦control directed at destroying harmful microbes
◦some viable microbes may persist
Disinfection is a relative term embracing a wide range of efficacy against particular
viruses, vegetative bacteria and fungi but not usually including spores
Disinfection is usually accomplished by the use of physical procedures or liquid
chemicals.
, Antiseptics
◦Disinfectants formulated for use on skin
◦Less powerful than disinfectants
◦An antiseptic opposes sepsis or putrefaction
either by killing microorganisms or by
preventing their growth
◦They destroy transient flora but leaving
untouched the resident skin flora deep in
the skin pores and hair follicles
, Antimicrobial Definitions
Germicide – Chemical agents capable of
killing microbes, spores may survive
Sanitization
◦The term implies to reduced microbial
population and is used to describe
disinfection, generally in conjunction
with catering and food equipment
,Decontamination
◦Item that has been treated to reduce number
of disease-causing organisms
◦General term for the treatment used to make
equipment safe to handle, and includes
microbiological, chemical, radioactive and
other contamination
, Nature of the item to be
treated
⚫For disinfection and
sterilization, the instruments and
items for patient care are divided
into 3 categories based on the
degree of risk of infection
involved in the use of the items
, Selection of Control
critical items have
◦ direct contact with body tissues
◦ needles, scalpels
Semi critical items have
◦ contact with mucous membranes but do not
penetrate
◦ endoscopes, endotrachial tubes
non-critical items have
◦ contact with unbroken skin. countertops, stethoscopes
,Methods of Sterilization
Two main method
Sterilization of sterilization
Physical and
Chemical chemical
Physical method Chemical method of
method (gaseous sterilization are
process) achieved usually by
gaseous process
, Methods of sterilization
Method Concentration or Level
Physical Sterilants
Moist heat -Steam under 121° C or 132° C for various time intervals
pressure and tyndallization Tyndallization at 1000C
Dry heat 1 hr at 171° C; 2 hr at 160° C; 16 hr at 121° C
Filtration 0.22- to 0.45-μm pore size; HEPA filters
Ultraviolet radiation Variable exposure to 254-nm wavelength
Ionizing radiation Variable exposure to microwave or gamma radiation
Gas Vapor Sterilants
Ethylene oxide 450-1200 mg/L at 29° to 65° C for 2-5 hr
Formaldehyde vapor 2%-5% at 60° to 80° C
Hydrogen peroxide vapor 30% at 55° to 60° C
Plasma gas Highly ionized hydrogen peroxide gas
Chemical Sterilants
Peracetic acid 0.2%
Glutaraldehyde 2%
