Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology > Sterilization And Disinfection > Flashcards

Sterilization And Disinfection Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

– the process by which most bacterial forms in non-living objects are destroyed, without necessarily destroying saprophytes and bacterial spores

A

DISINFECTION

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

refers to the use of chemical agents on skin or living tissues to inhibit or eliminate disease producing microorganism

A

Antisepsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

a gradual process and the kinetics of death are exponential

A

Heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

the relationship between sterilization and the temperature of exposure is expressed in terms of

A

Thermal death time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

the time required to kill a suspension of microorganism at a predetermined temperature in a specified environment

A

Thermal death time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

MECHANISMS OF THERMAL INJURY

A
  1. strand breaks in the bacterial DNA
  2. Loss of integrity of the membrane
  3. Denaturation of proteins
  4. Oxidative damage
  5. elevated levels of electrolytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Preferred over dry heat because of its more rapid killing action

A

Moist heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In moist heat

destroyed at 120 0C for 4 mins or 5.5 hrs at 100 0C

A

Endospores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Kills all vegetative forms of microorganisms at 80 – 100 C but not bacterial spores

A

Boiling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q
  • Used to sterilize materials that would be damaged by autoclaving
  • The material to be sterilized is exposed to live steam for 30 mins for 3 consecutive days
A

FRACTIONAL STERILIZATION (TYNDALLIZATION)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q
  • used in the processing of milk, foods and other beverages

- only inactivate disease producing microorganisms

A

Pasteurization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Expose milk at high temperature of _________followed by rapid cooling

A

60-65c

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

-Used in the sterilization of surgical instruments and bandages, culture media and other contaminated
materials

A

Steam under pressure (auto calving)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q
  1. STEAM UNDER PRESSURE (AUTOCLAVING)

- the steam is confined in a closed vessel pressure

A

reaches 15 psi  121 0C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How many minutes to sterilize the material in autoclave

A

15-20 minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q
  • requires higher temperature and longer period of exposure

- effectiveness depends on the ability of heat to penetrate the material to be sterilized

A

Dry heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Most widely used type of dry heat

A

hot air oven

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Dry heat use to sterilize

A

powders,
oils,
jellies and
glassware

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Other useful forms of dry heat

A

a. incineration

b. open flame

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

oDeprive the organism of moisture
oBacterial spores are not destroyed
oUsed in the preservation of foods

A

Desiccation or drying

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

oNot reliable because spores are not destroyed

oMany microorganisms can survive low temperatures

A

Freezing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

– a technique of preserving microorganisms by rapid freezing and dehydrating it in high vacuum and stored under vacuum in sealed ampule in cold storage

A

LYOPHILIZATION

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

A.ULTRAVIOLET LIGHT (UVL)

oMost effective wavelength =

A

240-280 nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Ultra violet oOptimum wavelength

A

260nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Radiation mechanism of actions

A

disrupts H bonds in microbial cell
 formation of thymine dimers
lethal frameshift mutations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

oUsed in sterilization of enclosed areas

A

Ultra violet light

27
Q

oHas greater penetrating ability than UVL

oPotentially hazardous to human cells

A

Ionizing radiation

28
Q

Ionizing radiation mechanism of actions

A

formation of free radicals
 chemically interact with proteins & nucleic acids
 cell death

29
Q

oForm of mechanical sieving  physical separation of microorganisms from the fluid

A

Filtration

30
Q

oUtilizes cellulose ester filters

A

Filtration

31
Q

Filtration

o0.22 um pore size – can filter almost all microorganisms EXCEPT

A

viruses,
Mycoplasma,
Chlamydia &
Rickettsia

32
Q

oBased on the principle of osmosis

A

Osmotic pressure

33
Q

Mechanism of action of osmotic pressure

A

When the concentration of the solution surrounding the bacterial cell is altered  collapse of the bacterial cell or may become
turgid

34
Q

Mechanism of ultrasonic vibration

A 
passage of sound through the liquid 
    produce alternating pressures 
    cavities form in the liquid 
 cavities    grow in size 
 burst 
 cells    disintegrate
35
Q

FACTORS AFFECTING DISINFECTION

A
  1. Concentration of chemical agent
  2. Time
  3. Temperature
  4. pH
  5. Nature of the medium
  6. Nature of the organism
36
Q

used as the standard in the evaluation of new chemical agents

A

Phenol

37
Q

designed to determine the ratio of the highest dilution that will kill the organism within a specified time to the greatest dilution of phenol showing the same result

A

Dilution test

38
Q

MECHANISMS OF ACTION OF CHEMICAL AGENTS

Interfere with normal membrane function  release of small metabolites and interfere with active transport and energy metabolism

A

Damage of the cell membrane

39
Q

– quarternary ammonium compounds

  • cause disruption of membrane & loss of membrane permeability
  • denatures proteins
  • most effective at alkaline pH
A

Cationic agents

40
Q
  • cause disruption of lipoprotein framework of the membrane
    - most effective at acid ph
    - e.g. soaps & detergents
A

Anioinic agents

41
Q
  • cause leakage of cell contents

- includes phenol and cresol

A

Phenolic compounds

42
Q

highly toxic to human cell

A

Phenol

43
Q

– phenol derivative

   - less toxic & more potent than phenol
   - e.g. lysol & creolin
A

Cresol

44
Q

disorganize lipid structure by penetrating into the hydrocarbon region

A

Alcohol

45
Q

AGENTS THAT DENATURE PROTEINS

A

a. acids & alkalis – alters the pH of the organism’s environment
b. alcohol & acetone
c. phenol & its derivatives

46
Q

poison the enzyme activity by forming mercaptides with the SH groups of cysteine residues

A

Heavy metals

47
Q

useful as antiseptics but not as disinfectants

A

Mercurials

48
Q

bactericidal

A

Silver compounds

49
Q

used in Crede’s prophylaxis

A

Silver nitrate

50
Q

used in burn patients

A

Silver sulfadiazine

51
Q

inactivates enzymes by converting functional SH groups to oxidized S-S form

A

Oxidizing agents

52
Q

Oxidizing agents includes

A
  1. Halogens

2. Hydrogen peroxide

53
Q

Halogens

A

Iodine

Chlorine

54
Q

– considered the best antiseptic

- bactericidal, sporicidal, fungicidal, virucidal & amoebicidal

A

Iodine

55
Q

– used as water disinfectant

- used in sanitizing food & dairy processing equipments

A

Chlorine

56
Q

– weak antiseptic

- used in cleansing of wounds, surgical devices & contact lenses

A

Hydrogen peroxide

57
Q
  • used in the treatment of dermatologic lesions

- used in staining bacteria

A

Dyes

58
Q

a. – highly selective for gram (+) bacteria

e. g. crystal violet, malachite green

A

triphenymethane dyes

59
Q

A kind of dye used as wound antiseptics

A

acridines

60
Q

Alkylating agents

A

Formaldehyde
Glutareldehyd
Ethelyne oxide

61
Q
  • sporicidal
    -used in preserving specimens &in the preparation of vaccines
    • used to destroy M. tuberculosis in sputum & fungus in athlete’s foot
    • used in the treatment of
      textiles
A

Formaldehyde

62
Q
  • sporicidal
    - 10 times more effective than formaldehyde
    - used as cold sterilant for surgical instruments especially respiratory therapy instruments
A

Glutaraldehyde

63
Q
  • sporicidal
    - used in gaseous sterilization of materials that would be damaged by heat like polyethylene tubes, electronic & medical equipments, biologicals & drugs
    - slow acting
A

Ethylene oxide

64
Q

– the process of completely destroying all microbial forms, including bacterial spores

A

STERILIZATION

Microbiology (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions