Bacte Lec - Quiz 1 Control of Microbial Growth Flashcards Preview

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Flashcards in Bacte Lec - Quiz 1 Control of Microbial Growth Deck (70):
1

process of destroying all forms of microbial life (vegetative cells and spores)


Sterilization –

2

special structures resistant to chemical and physical changes

• Spores

3

substance that prevents growth of bacteria by destroying cells or inhibiting growth; applied on skin

• Antiseptic

4

chemical agent that destroys only vegetative cells but not spores; applied on inanimate objects

• Disinfectant

5

process of killing or inhibiting the growth of pathogens

• Disinfection

6

kills bacteria, even without chemical agent it will not grow again

• Bactericidal

7

agent that kills microbes



• Microbicidal

8

inhibits growth of bacteria, but without chemical agent bacteria will grow again

• Bacteriostatic

9

chemical agent that inhibits and kills/destroys pathogens without damaging body tissues

Antimicrobial agent or antimicrobial drug

10

agent that kills fungi

• Fungicidal

11

agent that kills spores

• Sporicidal

12

agent that kills viruses

• Virocidal

13

MoA of 70% alcohol

1. Protein denaturation
2. Lipid dissolution

14

disinfectant, contains phenol, used in lab

Lysol

15

Mechanism of Action of Lysol

1. Inactivation of enzymes
2. Protein denaturation
3. Cytoplasmic membrane destruction

16

– disrupts cell membrane


Soap

17

agent that limits the growth of bacteria to a safe level

Sanitizer

18

Methods to Control Microbial Growth (11)

Heat
radiation
filtration
titration
agitation
osmotic pressure
sonic vibration
low temperature/ cold temperature
lyophilization
ethylene oxide
dessication

19

2 physical methods of sterilization under heat

moist heat
dry heat

20

why is moist heat better than dry heat

has faster coagulation of proteins

21

methods of sterilization under moist heat

autoclaving
boiling
Fractional/ Tyndallization/Intermittent
inspissation
pasteurization

22

pressure
temp
duration/time of autoclaving

121 C
15 pounds per square inch
15-20 min

23

methods of sterilization under moist heat
makes use of steam under pressure

autoclaving

24

methods of sterilization under moist heat
no incubation in between

autoclaving

25

advantages of autoclaving (3)

>Abundant moisture
>Penetrates rapidly
>Temperature above boiling

26

methods of sterilization under moist heat
not effective because it only kills vegetative cells

boiling

27

temp and time for boiling

100C
either within 10 min or 2-3 min

28

added when boiling to increase killing effect

2% sodium carbonate

29

methods of sterilization under moist heat
-uses Arnold’s sterilizer

Fractional/ Tyndallization/Intermittent

30

is Fractional/ Tyndallization/Intermittent effective

yes

31

time and temp for Fractional/ Tyndallization/Intermittent

-100C for 30 min for 3 consecutive days with incubation period in between (to allow spores to germinate and be killed the next day)

32

Fractional/ Tyndallization/Intermittent uses what type of sterilizer

Arnold’s sterilizer

33

methods of sterilization under moist heat
-uses an inspissator


Inspissation

34

methods of sterilization under moist heat
-used for high protein culture media that cannot withstand high temperature of autoclave

Inspissation

35

time temp days for inspissation

-75 – 80C for 2 hours for 3 consecutive days

36

Materials Inspissated:
(3)

 Dorset Egg Medium
 Lowenstein-Jensten
 Loeffler Serum

37

form of disinfection originally devised by Louis Pasteur to preserve wine
-but today it is more likely to associate with milk

Pasteurization

38

3 Ways by which Milk can be Pasteurized


a. High Temperature Short Time/ Flash Method

b. Low Temperature Cooling or Coding

c. Ultra-high Temperature (UHT)

39

3 Ways by which Milk can be Pasteurized
time and temp for High Temperature Short Time/ Flash Method

-milk heated at 72C for 15 sec

40

3 Ways by which Milk can be Pasteurized
time and temp for Low Temperature Cooling or Coding

-milk heated at 62C for 30 min

41

3 Ways by which Milk can be Pasteurized
time and temp for Ultra-high Temperature (UHT)

-dairy products stored without refrigeration
-milk heated at 72C to 140C and back to 72C for less than 5 sec

42

principle of dry heat

oxidation of cellular components

43

types of sterilization under dry heat

hot air
open flame
incinerator

44

time and temp for hot air

-160 – 180C for 1.5 hrs or 2 hrs

45

principle of open flame

burning to ashes

46

temp for incineration and for how long to incinerate

870 – 980C until burned into ashes

47

sterilizer of hot air

oven

48

equipment used in open flame

bunsen burner

49

equipment used in incineration

incinerator

50

method of dry heat sterilization
kills microbes rapidly

incineration

51

method to control microbial growth
-all types can be injurious, causing death or mutation

Radiation

52

2 types of radiation

ionizing and non-ionizing

53

MoA of dessication and lyophilization

removing water,

54

effect of dessication and lyophilization

dehydration

55

MoA of Low Temperature/Cold Temperature

changesin cellular proteins

56

MoA of osmotic pressure

plasmolysis

57

also called Sterilization/ Gas sterilization/ Gaseous-chemical sterilization

ethylene oxide

58

method of microbial growth control, uses a gas chamber

ethylene oxide

59

MoA of ethylene oxide

alkylation of nucleic acids of bacteria

60

how much chamber space
temp time
for ethylene oxide

450 – 750 mg/L of chamber space at 55 – 60C for 2 hours

61

– for inoculating microorganisms
-enclosed to protect from ____________ exposure
-with special filter paper: HEPA (High Efficiency Particulate Air) filter paper

Biological Safety Cabinet

62

special filter paper for biological safety cabinet

HEPA (High Efficiency Particulate Air) filter paper

63

MoA of titration and agitation

mechanical disruption of cell wall

64

MoA of sonic vibration

breaking of cell wall

65

removing microorganisms from solution or suspending fluid
-as fluid passes through filter, microbes are trapped in the pores of filtering material

Filtration –

66

effectivity of filtration depends on the ff

>Porosity
>Electric charge of filter
>Nature of fluid being filtered

67

Commonly Used Filters to Remove Microbes from a Suspending Fluid

1. Berkefeld filter – made of diatomaceous earth
2. Seitz – asbestos pad
3. Chamberland – unglazed porcelain
4. Membrane – cellulose ester/acetate
5. Morton – sintered glass

68

– used to determine effectivity of chemical agent

Phenol coefficient test

69

types of ionizing radiation

x-rays
cathode rays
gamma rays

70

non-ionizing radiation is also ___

ultraviolet radiation

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