chapter 5 (control of microbial growth) Flashcards
sterilization
absolute removal or destruction of all microorganisms and viruses (kills all spores)
what kills all spores?
sterilization
what kills all spores?
sterilization
disinfection, name an example
destruction of most bacteria including pathogens but does not kill all microbes
example would be chemical disinfectants
antisepsis , what is another way of saying it
(antiseptic), disinfection of skin or living tissue (less harmful compound) , normally using less harsh treatments (chemicals)
degerming, and name an example
removal of most microbes from a limited area, such as washing hands with soap and water
sanitization
lowering microbial counts to a safe level to meet public health standards
a little debrief
name all the terms and define what they mean
cidal vs. static/statis what does it mean
cidal means killing, and static means stop
a bacteriodical agent ___ the bacteria
kills
a bacteriostatic agent ___ bacteria from reproducing
stops
what does asepsis (aseptic) mean?
an area is a free significant contamination
modern surgical techniques are aseptic to minimize infection
asepsis/septic
kills microbes by destroying enzymes
bacteriocidal (germicidal)
boiling is an example of what?
this is an example of disinfection, not sterilization why? because most pathogenic bacteria are killed but not all endospores and most viruses are killed again but not all
explain pasteurization
sufficient to eliminate pathogens and to lower microbial numbers to slow spoilage.
what is a classic treatment for pausterization
mild treatment which is 63 for 30 minutes
what is the HST for pausterization (high temperature short time)
72 for 15 seconds
what is the UHT (ultra high temperature) for pasteurization, and what does it do?
140 for 3 seconds, it destroys all microorganisms that can grow under normal storage conditions
employs pressure (15 psi) and steam (121)
this isautocalve it kills all endospores in about 15 min. , best mothod for sterilization
what is the best method for sterilization
autoclave
autoclave and name what it is used for, or what it contributes
used for :
culture media
hospital instruments
hospital materials that can withstand heat and moisture
requires that all solid surfaces are exposed to steam
all liquids must reach a temperature of 121.
dry heat sterilization- several methods:
what are they?
direct flaming
incineration
hot air sterilization
used in microbiology laboratory to sterilize innocuation needles and loops
direct flaming
direct flaming, define it
used in microbiology laboratory to sterilize inoculation needles and loops, metallic must be red hot
effective way to dispose contaminated materials
incineration
define incineration
effective way to dispose of contaminated materials
drying oven
hot air sterilization
materials should stay at 170 for 2 hours in hot air sterilization. True or false
true
this is used for dry materials that are not temperature sensitive, name examples
hot air sterilization glassware, and some dry chemicals
define filtration
vacuum used to force liquid through filter with very small pores- 0.1 um ,0.22 um, or 0.45 um
this is used to sterilize temperature sensitive liquids such as antibiotics enzymes some vaccines
filtration
high efficiency particulate air (HEPA) filters
air filtration
this is used in operating room, air come inside the room
air filtration
this is used in some operating rooms to remove all microbes larger than 0.3 um.
air filtration
this has the ability to slows or slow growth microbial growth, is it bacteriostatic, germistatic, bacteriocidal, germicdial
refrigeration, and bacteriostatic & germistatic
stops microbial growth, is it bacteriostatic, germistatic, bacteriocidal, germicidial
freezing, bacteriostatic
name some characteristics of high pressure, in terms of liquid suspensions, bacterial cells, is it sterilization?
liquid suspensions treated with high pressure
may kill many bacterial cells- bacteriocidal, and this is not sterilization
define dessication
removal of water (drying)
- slows or stop growth-usually does not kill microbes-bacteriostatic
high concentration of salts and sugars
hypertonic environment
Answer the following question:
can osmotic kill all bacteria or just some bacteria, and name what it is in terms of static or cidal
it can only can kill some bacteria,and it is called bacteriostatic or bacteriocidal
what destroys the dna ?
radiation destroys the dna
x rays and gama rays _____ materials
penetrate
uv and high energy electron beams are not used on surfaces
false, they are use on surfaces
describe the characteristics of a microwave
do not kill microorganisms directly, they heat water, and if high temperature is used it can disinfect materials.
chemicals most can only be used for ______ and not ____
disinfection but not sterilization
define the disk diffusion method
disk of filter paper soaked in chemical disinfectant
placed on agar plate that has already been inoculated with bacteria
the plate is incubated until bacteria grow
zone of clearing determined effectiveness
Phenolic compounds (Phenols)
disrupt plasma membranes, denature protiens-bacteriocidal
very effective, remain active long after application
suitable for disinfection of soiled surfaces (ex.saliva, pus,and feces)
often mixed with other compounds to reduce toxicity
name some examples of phenols
original formulations of lysol
hexachlorophene - useful against bacteria that cause skin infections in new borns
useful against bacteria that cause skin infections in new borns , can be sued to disinfect surfaces in nursaries and caution must be used-causes neurologicla disorders
hexachlorophene
triclosan
used in some personal hygiene products -cosmetics and deodorant soaps
biguanides:
define what chlorhexidine
attacks plasma membrane- bacteriocidal
-to control microbes on skin and mucous membranes
used in surgical hand scrubs, can persist for up to 6 hours
only kills some viruses, does not destroy endospores.
define halogens
destroy proteins and membranes and used as disinfectants and antiseptics.
define what chlorine means and its contributions to the bacterial growth
forms hypochlorous acid in water-strong oxidizing agent- denatures enzymes
examples : household bleach- excellent disinfectant
chlorine dioxide -sterilizing gas
frequently used as an antiseptic, and include some examples:
tinture of iodine - in an alcohol solution
iodophore-linked to carrier molecule so that is released slowly over time
ex: betadine- used as antiseptic on skin
define 5 characteristics of alcohol
denatures proteins, disrupt membranes
kills bacteria and fungi
does not kill endospores and some viruses
acts quickly and evaporates
often used to disinfect surfaces in a lab, or degerm skin.
true or false. does alcohol usually suffice as an adequate antiseptic, and if compound to other chemicals it does not enhance effectiveness ?
false, it does not suffice an adequate antiseptic, however if mixed with other compound it enhance effectiveness.
what are the two types of alcohol used ?
ethanol and isopropanol
ethanol is how many percent effective?
70 percent effective
isopropanol is used as a
rubbing alcohol
what types of metals can inhibit the process of microbes?
copper, zinc, silver, and mercury
describe silver nitrate and what’s it contribution
used as eye drops for new born infants to protect against gonorrhoeal ophthalmia
define silver sulfadiazine
topical cream for burns
____ incorporated into bandages and catheters to ______ of microbes
silver ions , slow growth
define copper sulfate
used to inhibit algae in resorvoirs
define mercuric chloride
used to paint to control mildew (toxic)
define zinc chloride
used an antiseptic in mouthwash
regular soaps and detergent
does not work as disinfectants or antiseptics
important in mechanical removal of microbes
what does soap and water do in terms of washing your hands
soap breaks up the oily deposits and film on skin. Water can then wash these deposits away along with microbes
regular soaps and detergents works as
degerming the skin
Quaternary ammonium compounds (Quats):
Cationic detergents-
kill most bacteria, fungi, and some viruses
do not kill endospores
do not kill some gram negative bacteria
quaternary ammonium compounds (Quats): define a characteristic.
strongly antimicrobial, odorless, tasteless, colorless, and no toxic at low concentrations
ex: cepacol used as mouthwash
define if the statement is true:
some gram negative bacteria not only survive- but grow well in Quats
pseudomonas aeruginosa- causes what?
True, this statement is correct
pseudomonas aeruginosa cause of burn infections
what does gaseous chemosterilizers mean?
chemical gasses used for sterilization
what is ethylene oxide ?
ethylene oxide is a type of sterilization for chemical gases, it denatures proteins = germicidal
it also kills all microbes such as endospores and viruses
does ethylene oxide require 4-18 hours of exposure, and is it a fact that it is not highly penetrating-cannot pass through plastics?
false. although it requires 4-18 of exposure, it does allow passing through plastics
can ethylene oxide be used to sterilize disposable hospital equipment and lab supplies?
yes it can be used
name some examples of ethylene oxide
plastic tubing
disposable swabs
oxidizing agents are:
hydrogen peroxide
ozone
benzoyl peroxide, name what they all do and their function
oxidize and denature proteins
useful against anaerobic organims
hydrogen peroxide- common antiseptic for wounds
ozone-used with chlorine to disinfect water
benzoyl peroxide- used an antiseptic on skin
- kills anaerobic bacteria living in tissues
ex: bacteria that cause acne
