Sterilization, Disinfection and Antisepsis Flashcards
what is cross infection
transmission of infectious agents among patients and staff in a clinical environment
what are cross infection risks in dentistry
- patients with infectious disease
- patients in the prodromal or convalescent stage of infection
- healthy carriers
- environmental sources
what are universal precautions
all patients are treated as though they are a potential source of infectious pathogens
what are the airborne routes for spread of cross infection
- dust borne routes: staphylococcus from skin scales, clostridium tetani from enivronmental dust
- aerosol routes: large droplets, droplet nuclei, speaking, sneezing
what are the contact routes of cross infection
-person to person: direct spread by hands or clothes or fomites
- equipment: dental instruments, chairs, impression materials
- fluids: dental water supplies
what are the sources, ,inoculation, and prevention of parenteral spread of cross infection
- blood, saliva, secretions
- eye, skin breach, mucous membranes, sharps injury
- training in use and disposal of sharps, Hep B vaccine, wear gloves, dress wounds
what is sterilization
destruction of all microbial forms
what is disinfection
destruction of most microbial forms
what are disinfectants used on
inanimate objects
what is antisepsis
inhibition or eliminatino of microbes on living tissue
what are antispetics
chemical agents that kill or inhibit growth of microorganisms when applied to tissue
what is sanitization
reduction of microbial population to levels deemed safe
what do -cidal agents do
kill
what do - static agents do
inhibit growth
what is the pattern of microbial death
- not killed instantly
- population death occurs exponentially
- microorganisms are considered to be dead when they are unable to reproduce in conditions that normally support theirreproduction
what are the conditions influencing the effectiveness of antimicrobial agent activity
-population size
- population composition
- concentration or intenstiy of an antimicrobial agent
- duration of exposure
- temperature
- local environment
what are the use of physical methods in control
-heat
- low temperatures
- filtration
- radiation
what does moist heat do
- effective against all types of microorganisms
- degrades nucleic acids, denatures proteins and disrupts membranes
what is dry heat sterilization
- less effective, requiring higher temperatures and longer exposure times
-oxidized cell constituents and denatures proteins
what is thermal death time
shortest time needed to kill all microorganims in a suspension at a specific temperature and under defined conditions
what is decimal reduction time
time required to kill 90% of microorganisms or spores in a sample at a specific temperature
what is the Z value
increase in temperature required to reduce D to 10% of original value
what do autoclaves do
- used to kill endospores efficiently
- used saturated steam under pressure to reach temperature above boiling
what is pasteurization
controlled heating temperature well below boiling
- reduced total microbial population and thereby increases shelf life of treated material
what is flash pasteurization
-high temperature short term
- 72 degrees C for 15 seconds
what is ultrahigh temperature sterilization
140- 150 degrees C for 1 to 3 seconds
what does freezing do
-stops microbial reproduction due to lack of liquid water
- some microorganisms killed by ice crystal disruption of cell membranes
what does refrigeration do
slows microbial growth and reproduction
what does filtration do
reduced microbial population or sterilized solutions of heat sensitive materials by removing microorganisms
what are depth filters
thick fibrous or granular filters that remove microorganisms by physical screening, entrapment and or adsorption
what are membrane filters
porous membranes with defined pore sizes that remove microroganisms primarily by physical screening
what are ways to filter air in the office
-surgical maska
- high efficiency particular air filters
what does UV radiation do
limited to surface sterilization because UV radiation does not penetrate glass, dirt films, water and other substances
what does ionizing radiation do
- penetrates deep into objects
- destroys bacterial endospores; not always effective against viruses
- used for sterilization and pasteurization of antibiotics, hormones, sutures, plastic disposable supplies and food
what do phenolics do
- used as laboratory and hospital disinfectants
- denature proteins and disrupt cell membranes
- tuberculocidal, effective in presence of organic material and long lasting
- disagreeable odor and can cause skin irritation
what do alcohols do
- bactericidal, fungicidal but not sporicidal
- inactivate some viruses
- denature proteins and possibly dissolve membrane lipids
- 60-90% in water
what does iodine do
- skin antiseptic
- oxidizes cell constituents and iodinates proteins
- at high concentrations may kill spores
- skin damage, staining, and allergies can be a problem
what does chlorine do
- oxidizes cell constituents
- important in disinfection of water supplies and swimming pools, used in dairy and food industries, effective household disinfectant
- destroys vegetative bacteria and fungi but not spores
- can react with organic matter to form carcinogenic compounds
what do heavy metals do
-effective but usually toxic
- combine with and inactivate proteins; may also precipitate proteins
what do quaternary ammonium compounds do
- detergents: organic molecules with hydrophilic and hydrophobic ends. act as wetting agents and emulsifiers
- cationic detergents are effective disinfectants: kill most bacteria but not M tuberculosis or endospores
what do aldehydes do
- highly reactive molecules
- sporicidal and can be used as chemical sterilants
- combine with and inactivate nucleic acids and proteins
what do sterilizing gases do
- used to sterilize heat sensitive materials
- microbicidal and sporicidal
- combine with and inactivate proteins
