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sterilization
kill all vegetative cells and spores
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disinfection
reduces number of pathogens on an inanimate surface (sanitation)
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Decontamination
makes contaminated surfaces safe to handle by reducing the number of microbes present
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Antispesis
killing microbes on living tissue
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antibiotic
antimicrobial compound made by one living organism that affects other organisms
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bacteriostatic
inhibits growth
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bacteriolytic
kills and lyses cells
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what is difference between disinfection and antispetic
- disinfection is for INANIMATE objects
- antiseptci is use don living tissue
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who was first person to come up with antibiotic
- Flemming - pennicilium
- but didn't know method to extract chemical from from fungus
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what was first organism to be treated by antibiotic
- S. aureus
- now it is first to mutate and become resistent to antibiotics
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D-value =
time it takes to kill 90% of cells in broth tube
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what affects D- value
- temp
- type of organism
- physiclogical state
- other
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thermal death point =
the lowest possible temp that will achieve complete killing with ten minutes
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thermal death time
the min time to achieve complete killing in a liquid solution at a given temperature
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inceneration =
flaming loop
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baking
- requires long period
- 160C for 2 hr
- 171 C for 1 hr
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physical ist heat include
- boiling
- tyndallization = discontinuous boiling
- pasteurization
- autoclaving
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boilng wll not kill
endospores
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tyndallization =
discontinuous boiling
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autoclaving
- moist very heigh heat
- steam pressure
- temps higher than boiling
- kills spores
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pastuerization commonly used for
- juice, beer , milk and other dairy products
- kills spores
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physical cold =
- freezing
- refrigeration
- Advantages = many products tolerate cold better
- Disadvantages = very little killing and is expensive
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disadvantage of heat =
materials must withstand high temps
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filtration is a .... way of removing microbes
physical
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disadvanage of filtration
viruses not eliminated and must be either liquid or gas
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types of radiation used to kill microbes
- ultrviolet
- gamma rays
- x ray
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ultraviolet does what
damages DNA and poor penetration
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gamma ray advantage =
very good penetration
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disadvantage of xray
poor penetration power
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radiation damages microbes by ....
- prymidine dimer
- adenine and thymine link is disrupted
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purines include
guanine and adenine
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the prymidines
cytosine, thymine, uracil
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choice of disinfectant is based on
- nature of object
- kinds of micorbes targeted
- desired effect
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Phenolics are an do what
- denature proteines
- disrupt membranes
- effective on surfaces
- too toxic to apply to tissue
-
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alcohols are what and do what
- denature protein
- disrupt membranes
- most effective at 50-70%
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examples of alcohols
ethanol and isopropanol
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range of use for alcohol
50 - 70 %
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alcohol is preferred for
tissue
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two groups of oxidizers =
metallic and non-metallic
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halogens include
chlorine and iodine
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what do oxidizers do
damage proteins and lipids
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hydrogen peroxide =
an oxidizer weak antiseptic
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how do metallic oxidizers inhibit microbial growth
oligodynamic effect
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oligodynamic effect
- clear zone of inhibition
- affect associated with heavy metals
- bacterialcidal effect
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surfactants are and do
- disrupt membranes
- example = quats (quaternary ammonium compounds) soaps, detergents
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surfactants are what type of compunds
amphiphilic
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amphiphillic =
hydrophillic and hydrophobic
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alkylators are and do
- damage proteins or DNA by carbon adducts
- used to sterilize via gas
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and adduct is
a product of a direct addition of two or more distinct molecules, resulting in a single reaction product containing all atoms of all components.
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