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Microbiological control & Virology > Ch 11 > Flashcards

Ch 11 Flashcards

1
Q

Sterilization -

Sterile-

A
  • process that destroys or removes ALL viable organisms
  • critical objects and noncritical items require sterilization

-the absence of absolutely ALL viable microbial life
reserved for inanimate objects because it would be dangerous if preformed on living tissues

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2
Q

Disinfection-

Disinectant-

A
  • a process that destroys all viable microbes including viruses and endosores
  • semi-critical objects and noncritical items require disinfection

-destroys vegetative pathogens but not bacterial endospores

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3
Q

sanitization

A

any cleansing technique that meachanically removed microbes

ex)
soaps, detergents

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4
Q

degaermation

A

reduces the number of microbes through mechanical means

ex)
surgical handscrub, alcohol whipes, germical soaps

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5
Q

microbial agents

A

agents that cause microbistasis

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6
Q

microbistasis

A

microbes are temporarily prevented from multiplying but are not killed

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7
Q

microbicide (germicide)

A

any chemical agents that kill pathogenic microorganisms

end in (-cide)

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8
Q

modes of action

A
  1. the cell wall
  2. the cell membrane
  3. protein and nucleic acid synthesis
  4. proteins
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9
Q

effects of agents on cell wall

A

a cell derived of a functioning cell wall becomes fragile ans lysed

ex) ~agents~
detergents, alcohol

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10
Q

effects of agents on cell membrane

A

cell loses selective permeability and cannor prevent loss of vital moleculed> death

ex) ~agents~
detergent surfactants

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11
Q

effects of agents of protein and nucleic acid synthesis

A

blocked process of replication, transcription, translation result in some mutations

ex)
uv radiation

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12
Q

effects of agents on protein function

A

denatured proteins. misfolding
loss of normal protein function can arrest metabolism and exert broad effects on microbes

ex)
alcohols, phenols, acids, heat

denaturization can occur via coagulation by moist heat

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13
Q

effects of agents on protein function

A

denatured proteins. misfolding
loss of normal protein function can arrest metabolism and exert broad effects on microbes

ex)
alcohols, phenols, acids, heat

denaturization can occur via coagulation by moist heat

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14
Q

microbial death (detemination)

A

Nonviable if microbial cell sustains metabolic/structural damage to an extent that it can no longer reproduce

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15
Q

factors that affect death rate

A
  1. legnth of exposure
  2. effects of microbial load(quantity)
  3. resistance of endospores
  4. action of agent (microbicidal or microstatic)

note:
agents target a cell’s metabolic process *active cells die more rapidly

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16
Q

highest resistance:

moderate resistance:

least resistance:

A 
(highest)
        prions:
             -protenaceous infectious particles
             -bacterial endosores
bacillus and clostridium
(moderate)
        -protozoan cysts:
                 -some fungal spores
                 -some viruses
                 -naked virusrs
mycobacterium,  pseudomonas,  staphylococcus
(low)
     bacterial vegetative cells
     fungal spores
     hyphae
     enveloped viruses
     yeast
     protozoan trophozoites
17
Q

methods of physical control

A
  1. heat (moist and dry)
  2. cold temperatures
  3. Disiccation
  4. Radiation
  5. Filtration
18
Q

moist heat

  • moist heat
  • boiling water
  • pastirization
A

(moist heat)

  • lower temperatures and shorter exposure time
  • coagulation and denaturation of proteins
   (pressurized steam)
       -Sterilant
       -AUTO-CLAVE
   (nonpressurized steam)
       -TYNDALYZATION- intermediate sterilant

(boiling water)
-disinfection

(pastirization)

   - Disinfection
   - kills nonendosporeforming pathogens
   - doesn't kill endospores or nonpathogenic microbes
   - uses FLASH METHOD
   - targets salmonella, brucella, lysteria monocytogenes
19
Q

Dry Heat

- incineration
- desication
- cold
A

(dry heat)

  • moderate to high temps
  • dehydration, alters protein structures, incineration
  • lack of water increases stability of some protein conformations
    (incineration)
         -ignites and reduces microbes and other substances
    (desication)
          -dehydrated
    (cold)
          -MICROSTATIC
          -slows microbe growth
    ex)
       s. aureus, clostridium, listeria
20
Q

Radiation

A

(Radiation)
-energy emmited from atomic activities and dispersed at high velocity through matter and space

(modes of action)
>ionizing
-energy rejects electron from an atom
-gamma rays, x-rays, cathode rays
>nonionizing
-excited atom by raising to higher energy state
-formation of double bonds
-mutations
-UV rays

21
Q

Ionizing Radiation
(cold radiation & irradiation)

ex)
-gamma rays, x-rays, cathode rays

A
  • sterilant
  • preserving food

> benefits

  • 50%fewer infections and deaths
  • can sterilize sensitive materials
  • more penetrating than nonionizing radiation

> disadvantages
-factory exposure to radiation

22
Q

Non-ionizing Radiation

ex)
-UV rays

A
  • disinfection
  • sterilizing air, water, or surfaces
  • as UV passes through a cell it is readily absorbed by pyrimidine bases&raquo_space;forming pyrimidine dimers
    - pyrimidine dimers interferes with normal DNA Replication, and transcription&raquo_space;> lead to inhibition of growth and cellular death
  • produces free radicals(toxic photochemicals)
    - free radicals bind to DNA, RNA, or proteins»interfere with essential cell processes

> disadvantages

  • UV has poor powers of penetrating solids
  • UV has damaging effects on human tissues
23
Q

Filtration

A
  • physical removal of microbes passing through a gas or liquid through a filter
  • sterilize heat sensitive liquids and air

ex)
blood products, vaccines, drugs, enzymes

24
Q

Levels of decontamination

A

(High-level germicide)

  • Sterilants
  • not heat sterilizable and intend to be used in sterile environments (body tissues)

(Intermediate-level germicide)

  • disinfectants
  • kill fungal spores, tubercle bacillus, viruses
  • disinfect contact with mucous membranes, but not invasive

(Low-level germicide)

  • eliminate only vegetative bacteria
  • clean surfaces that touch skin but not mucous membranes
25
Q

Factors that affect germicidal activity

A
  • time of exposure
  • strength and mode of action
  • nature of material being treated
  • degree of contamination
26
Q

Categories of germicides (11)

A

1) Halogens
2) Phenol
3) Chlorhexidine
4) Alcohols
5) Hydrogen Peroxide
6) Aldehyde
7) Gaseous sterilants
8) Detergents and Soaps
9) Heavy metals
10) Dyes
11) Acids and Alkalines

27
Q

Sterilants List

A
  • Pressurized steam
  • Nonpressurized steam (intermediate/tyndalyzation)
  • Ionizing radiation
  • Filtration (?)
  • Glutaraldehyde (aldehyde)
  • Ethylene oxide (gas)
  • Chlorine dioxide (gas)
28
Q

Disinfectants List

A

-nonionizing radiation
-pasteurization
-boiling water
-Detergents (low-level)
-Hydrogen Peroxide
-dyes(low-level)
(gases-all)
-Formaldehyde (intermed-high level, aldehyde)
-ortho-pthaldehyde (high-level)
-ethylene oxide(also sterilant)
-propylene oxide
-betaproplolactone

Microbiological control & Virology (4 decks)

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