Ch 7 Controlling the Growth of Microbes Flashcards
(32 cards)
1
Q
sterilization
A
- remove or destroy all forms of microbial life
2
Q
disinfection
A
reduce number of vegetative pathogens to level that is safe
3
Q
antisepsis
A
disinfection of the skin or other tissues
4
Q
degerming
A
physical removal of harmful microbes
5
Q
sanitization
A
lowering microbial levels to “safe” levels
6
Q
sepsis
A
bacterial contamination
7
Q
asepsis
A
absence of contamination
8
Q
the control of microbes is
A
- not used to treat disease but reduces transmission and limits exposure
- may involve physically removing microbes from surfaces
- may be microbicidal (killing) or microbistatic (inhibits)
9
Q
Physical means of control of bacteria
A
- heat
- cold
- desiccation
- radiation
- filtration
10
Q
chemical means of control of bacteria
A
- targets: cell wall, cell membrane, proteins, cellular processess
11
Q
heat
A
- dry heat
- weat heat: boiling water, steam
- pasteurization: batch, flash, UHT, UHS
12
Q
autoclave
A
15 psi, 121 C, 15 min
13
Q
dry heat sterilization
A
- flaming and incineration
- hot air baking (171 c/1hr or 160 c /2 hrs)
14
Q
cold and desiccation
A
- cold temperatures (below 20 C) retards growth
- freezing causes cell damage by ice crystal formation
- removal of water retards growth: drying or salt preservation
15
Q
radation
A
- ionizing radiation
- non-ionizing radiation
16
Q
ionizing radiation
A
- forms ions on variety of cellular chemicals
- x-rays, gamma rays
17
Q
non-ionizing radiation
A
- uv radiation: damages DNA
18
Q
filtration
A
- exclusion filtation (filtering out microbes through holes of a particular size): membrane filters
- HEPA (air pushes outmicrobes and air is recirculted)
19
Q
Chemicals
A
- halogens
- Phenol
- alcohols
- peroxides
- heavy metals
- aldehydes
- quaternary ammonium
- detergents
20
Q
henols
A
denature proteins and disrupt membranes
21
Q
alcohols
A
- denature proteins and disrupt membranes
22
Q
halogens
A
- oxidize enzymes and disrupt membranes
- iodine: iodophors: iodine-containing organics
- cholrine: hyprochlorite
23
Q
peroxides
A
- oxidizing agents
24
Q
heavy metals
A
- Hg, Ag, Cu, Ar
- interfere with protein function
25
Aldehydees
- H-C=O
- denature proteins
- effective at low concetration
26
detergents (surfactants)
- reduce surface tension of water
- dissolve lipids
- quaternary ammonia compounds
27
quaternary ammonia compounds
- zepheron
| - allows remove of non-polar and organic material
28
Gases
- ethylene oxide, propylene oxide
- denature proteins and DNA
- highly toxic, flammable
29
variables of application
- concetration
- timing
- temperature
- pH
- Nature of material
30
disinfection
- removal of harmful microbes usually from inanimate surface
31
antisepsis
- removal of potential pathogens from living tissue
32
most resistant to least resistant
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Prions
endospore
mycobactera
cysts of protozoa
vegetative protozoa
gram negative
fungi (fungal spore)
viruses withouth envelopes
gram-positive
viruses with lipid envelopes
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