Mod 6 Flashcards
What are the four principle methods for inhibiting growth and destroying microbes?
- Sterilization
- Disinfection
- Sanitation
- Cleaning
What is sterilization?
It destroys all forms of microbial life
Something can be “sort of” sterile. (T/F)
False! It’s either sterile or not! Absolute terms
What does disinfection mean?
When referring to the elimination of all pathogens but not all microbial forms on INANIMATE objects
What does terminal disinfection mean?
It describes a procedure that is carried out after the patient has left the procedure area
What does antisepsis mean?
Disinfection of tissue (usually skin or mucous membrane)
What does sanitation mean?
Removal of pathogenic microorganisms from inanimate objects by mechanical or chemical means
What’s a main object that the term sanitation is describing?
Process eating utensils and dishes
What’s the difference between sanitation and disinfection?
Disinfection = usually chemical Sanitation = mechanical OR chemical
What are the three methods of sterilization?
- incineration
- autoclave
- ethylene oxide
What are some examples of used materials that require sterilization before disposal?
wound dressings and discarded lab cultures
What do dry heat (hot air ovens) do?
It penetrates substances slowly compared to moist heat
What are hot air ovens used to sterilize?
metal objects, glassware, and sterilizing oils and powders
How long do you keep the items in a hot air oven if the temperature is 171c?
1 hour
How long do you keep the items in a hot air oven if the temperature is 160c?
2 hours
How long do you keep the items in a hot air oven if the temperature is 121c?
16 hours or longer depending on the volume
What does incineration mean?
To burn or reduce to ashes
What are some examples of material that is suitable for incineration?
- used needles and syringes
- IV sets
- used gloves
- discarded bandages
- discarded lab cultures
- blood samples
what is an autoclave?
a well-controlled pressure cooker that uses steam under pressure to kill microorganisms
In an autoclave, the pure steam yields what temperature?
121c
Since autoclaves use moist heat, how long will it take to kill microbes?
15 minutes
What is the purpose of a safety valve on an autoclave?
to allow steam to escape if the pressure exceeds safety limits
What are the three strips on a spore control?
1) positive growth control (not autoclaved)
2/3) into the autoclave, then incubated in a broth medium to see if the autoclave actually works
What does a fluoresce reading indicate?
autoclave isn’t working properly
what does no fluoresce indicate?
autoclave is working properly
How long does a sterilization cycle with the use of ETO sterilizers?
up to 8 hours followed by a minimum of 24 hours at room temp
What are some desirable properties of disinfectants?
- broad spectrum
- rapid action
- resistance to inactivation by other material
- non-toxic
- odorless
- non-destructive
- residual action
- user friendly
- economical
What are the three categories of Spaulding’s classification for inanimate materials?
- critical items
- Semi-critical items
- non-critical items
What are critical items?
Items that come into contact with normally sterile human tissue; these are items that need to be sterile
What are semi-critical items?
Items that come into contact with non-sterile mucous membranes/body surfaces; need to be free of pathogens, but don’t need to be sterile
What are non-critical items?
Items that come into contact with skin but not mucous membranes; surfaces need to be free of pathogens that can cause infections when inhaled
How are disinfectants usually classed?
In accordance to their level of germicidal action
What are some examples of least resistant microbes?
vegetative bacteria, lipid viruses, fungi, non-lipid viruses and tubercle bacilli
What are the most resistant types of microbes?
bacterial spores
What do low level disinfectants kill?
Vegetative bacteria and lipid viruses
- not expected to kill fungi
What do intermediate level disinfectants kill?
vegetative bacteria, lipid viruses, fungi, and tubercle bacilli
- not expected to kill non-lipid viruses or spores
What do high level disinfectants kill?
vegetative bacteria, lipid viruses, fungi, non-lipid viruses, tubercle bacilli and bacterial spores AT AN EXTENDED PERIOD OF TIME
What does pasteurization kill?
vegetatitve bacteria, viruses and fungi
What is the temperature at which pasteurization is done at?
75c-77c
what level of disinfection does pasteurization do?
intermediate level disinfection
What shouldn’t women consume while pregnant to prevent possible ingestion of ___?
unpasteurized cheese, Listeria
What are the two main types of filtration?
Membrane and HEPA
What are membrane filters?
very thin filters with small pores that cause microbes to get stuck on the surface of the filter
What are HEPA filters?
they’re thick filters that have convoluted passages for air to flow through
Items that are sterilized with liquid chemicals are ____.
Critical items
When residues aren’t removed with sterile water, the item will be called _____.
semi-critical
Soaps and detergents act as _____ agents and they ____ surface tension.
Wetting agents and reduce surface tension
What are some examples of low level disinfectants?
soap and detergents, quatenary ammonium
What are some examples of intermediate level disinfectants?
alcohols (~70%), chlorine-containing, iodophores, complex phenolic compounds
What are some examples of high level disinfectants?
glutaraldehyde, peroxygens
What is the wavelength range of UV radiation?
40-390 nm
What is the most effective UV wavelength to kill microorganisms?
200 nm
How does UV radiation kill microorganisms?
It damages their DNA and proteins
What do radiation, microwave radiation and strong visible light do?
They are used to control microbial growth
What does boiling water do?
It destroys vegetative cells of most bacteria, fungi and protozoal parasites
How long does it take for boiling water to kill certain microbes?
10 minutes
Can boiling water kill viruses?
No–it only inactivates it
What does aseptic mean?
without sepsis = without infection
What is another term for aseptic technique?
sterile technique
What’s the ranking for places you are likely to find the highest number of bacteria to least?
in or on a person > moist areas, dry areas > air
- Destroys pathogens, but not spores
- May be used for some tubing
- Used for milk
pasteurization
Used to remove microorganisms from liquids such as pharmaceuticals
membrane filters
used to remove microorganisms from air by trapping them on fibres
HEPA filters
used to remove microorganisms from surfaces by trapping them in fibres
microfibre cloths
- The sun is a natural source
- used on surface such as those in operating rooms
- does not pass through glass or plastic
UV light
used to destroy pathogens in spices and on food (especially meats)
ionizing radiation
- uses water heated to 100c
- may not kill spores
boiling
- destroys pathogens, but not spores
- may be used for some tubing
- used for milk
autoclave
items are burned
incineration
good for heat sensitive plastics
ethylene oxide
intermediate
- often used in disinfectant soaps
- may be used in low concentrations as an oral rinse
phenolics
intermediate
- must be diluted fresh daily (1/10)
- may corrode metals
- good surface disinfectant
chlorine
intermediate
- often used for pre-operative skin disinfection, may be allergenic
iodine
high level
- liquid that may be used to sterilize heat-sensitive items
- toxic fumes
- must be rinsed off
glutaraldehydes
high level
- may be used to sterilize complex items such as endospores
- active ingredients are hydrogen peroxide and peracetic acid
peroxygens
low level
- good wetting agents
soaps/detergents
low level
- often used in combo with other products
- might allow growth of gram negative organisms
quats
intermediate level
- often used as a 70% concentration for skin antisepsis
alcohols
What does incineration do?
burning the materials at a high temperature
What does an autoclave do?
steam under pressure; moist heat
What is ethlyene oxide?
a gas sterilization method; no heat
What are the cons of ETO?
it’s toxic to human tissue
it’s also time consuming and expensive
