U1 LAB: CONTROL OF MICROBIAL GROWTH Flashcards
1
Q
Factors affecting Microbial Growth
A
- Type of Organism
- Microbial load
- Concentration of agent
- Presence of organic material
- Nature of surface (to be disinfected)
- Contact time
- Temperature
- pH
- Compatibility of disinfectants
2
Q
This is the causative agent of Mad Cow Disease/CJD and is made up of proteins.
A
Prions (most resistant, need to burn for it to be killed)
3
Q
This refers to the absence of microbes in an area or object.
A
Asepsis
4
Q
This refers to the methods employed to prevent entry of organisms to body, or equipment used for microbial cultivation.
A
Aseptic Technique
5
Q
This involves chemical disinfection of living tissues, as well as in treatment of wounds.
A
Antisepsis
6
Q
Chemical agent used in antisepsis
A
Antiseptic
7
Q
This is a condition in which microbial growth and multiplication is halted or inhibited.
A
Bacteriostasis
8
Q
Bacteriostatic methods include?
A
refrigeration, dyes
9
Q
These are chemical sterilants used to destroy all forms of life.
A
Biocide
10
Q
Other term for biocide
A
Chemical sterilants
11
Q
These are inadvertently introduced to specimens or culture.
A
Contaminant
12
Q
This is the process of removal of pathogenic microorganisms so materials are safe to handle/dispose.
A
Decontamination
13
Q
This refers to the removal of transient microorganisms from the skin.
A
Degerming
14
Q
This is the process of destruction of pathogenic microorganisms except spores, prions, and others.
A
Disinfection
14
Q
Degerming methods include?
A
mechanical cleansing, use of antiseptics
15
Q
This refers to the reduction of pathogens on eating utensils to safe public health levels.
A
Sanitization
16
Q
Sanitization methods include?
A
mechanical cleansing, use of chemicals
17
Q
This is the destruction of all forms of life including bacterial spores.
A
Sterilization
18
Q
This is the lowest temperature in which all bacteria in culture will be killed in 10 minutes.
A
Thermal Death Point
19
Q
This is the minimal length of time in which all bacteria in liquid suspension will be killed at a given temperature.
A
Thermal Death Time
20
Q
Methods of control
A
Physical Means and Chemical Means
21
Q
Physical Means require the use of?
A
heat
22
Q
Chemical Means require the use of?
A
alcohol
23
Q
This is the most commonly used physical method.
A
Heat
24
2 types of heat
Moist Heat, Dry Heat
25
Principle of Dry Heat
Oxidation
26
Examples of Dry Heat
Oven (for glasswares, 3 hours)
27
Dry Heat
longer exposure time, ___ temperatures
higher
28
This is used to sterilize glasswares.
Hot Air Oven
29
Temp requirements for dry heat
160-180C for 1.5-3 hours
30
Examples for open flame
Bunsen burner, Alcohol lamp
31
This is used for the sterilization of inoculating loops, needles, mouth of tubes.
Open Flame/Flame sterilization
32
This is the only way to destroy prions, and is used for disposal of hospital infectious waste.
Incineration (Incinerator)
33
Incineration is outlawed by?
RA 8749 (Clean Air Act of 1999)
34
Other term for Moist Heat
Heat under Steam Pressure
35
Principle of moist heat
Coagulation of Proteins
36
T/F: Dry heat is more effective than moist heat
False
37
Moist Heat
_____ time of exposure
shorter
38
Moist heat is the sterilization method choice for?
heat stable objects
39
Temp requirements for Autoclaving
121C, 15psi (1 atm) for 15 minutes
40
This kills all microorganisms except prions.
Autoclave
41
T/F: In opening the autoclave, you must let it cool down first to decrease pressure inside.
True
42
This is a form of disinfection under heat that doesn't kill spores.
Boiling
43
Temp requirements for boiling
100C for 10-15 minutes
44
This eliminates food borne pathogens responsible for food spoilage.
Pasteurization
45
Methods under Pasteurization
- Batch Method
- Flash Method
- High tempt short time
46
Batch Method
63C for 30 minutes
47
Flash Method
72C for 15 seconds
48
High Tempt Short Time
72C-140C then 72C for <5sec
49
This refers to a flowing steam, is fractional and intermittent.
Tyndallization
50
Tempt requirements for Tyndallization
100C for 30 mins for 30 days
51
1st day of Tyndallization
kills vegetative states of bacteria
52
2nd day of Tyndallization
endospores enter vegetative state
53
3rd day of Tyndallization
kills endospores in vegetative state
54
This is used for sterilization of high protein media.
Inspissation
55
Tempt requirements for inspissation
75-80C for 2 hours on 3 consecutive days
56
This physical method is used to seperate bacteria from liquids or air.
Filtration
57
Filtration of liquids is done through:
- Berkefield
- Morton
- Seitz
- Chamberland-pasteur
- Membrane filters
58
Berkefield uses?
diatomaceous earth
59
Morton uses?
sintered glass
60
Seitz uses?
asbestos pad
61
Chamberland-Pasteur uses?
unglazed porcelain
62
Membrane filters use?
Cellulose esters
63
Critical sterilization uses?
0.22um filter
64
The use of liquid filtration is?
Sterilization of heat sensitive solutions
65
Filtration of air is through?
HEPA filters
66
HEPA stands for?
High Efficiency Particulate Air
67
HEPA filters are able to remove what size of organisms?
>0.3um
68
Use of HEPA filters can be seen in?
Laboratory hoods, rooms of immunodeficient patients
69
This physical method can either be ionizing or non ionizing.
Radiation
70
MOA of Radiation
alkylation of nucleic acid
71
Ionizing uses what rays?
Gamma rays / Electron beams
72
Ionizing
Short wavelength, ______ energy
high
73
Use of Ionizing radiation
Sterilization of disposable materials
74
Non Ionizing uses what rays?
UV rays
75
T/F: UV rays have poor penetration
True
76
Use of Non ionizing radiation
Sterilization of surfaces
77
This is a physical method used to remove water to stop metabolic action of bacteria/
Dessication (dehydration)
78
This is a physical method that uses high concentrations of sugar/salts.
High osmotic pressure
79
High osmotic pressure can be done through?
Plasmolysis
80
This is a bacteriostatic physical method.
Exposure to low temperature
81
This chemical is used for cold sterilization.
Ethylene Oxide
82
Ethylene oxide utilizes a?
gas chamber with 450-700 mg/L volume
83
Minimum time for Ethylene oxide
2 hours
84
Principle of Ethylene oxide
Alkylation of nucleic acids
85
These gaseous chemicals have a shorter time of killing.
Hydrogen Peroxide and Periacetic Acid
86
MOA of Alcohol
Protein Denaturation and Lipid Dissolution
87
Alcohol can penetrate the?
plasma membrane
88
Examples of alcohol
70% Ethanol
89
MOA of Aldehydes
Alkylation of Nucleic Acids, Protein Denaturation
90
Examples of Aldehyde
- 2% Glutaraldehyde
- 40% Formalin
91
This is a disinfectant under Aldehydes.
2% Glutaraldehyde
92
This has a bactericidal property under Aldehydes.
40% Formalin
93
This can be used as an alternative for those who are allergic to Iodine.
Chlorhexidine
94
MOA of Chlorhexidine
Cytoplasmic Membrane Destruction
95
Uses of Chlorhexidine
Commonly used antiseptic in surgery
96
MOA of Halogens
Oxidation of cellular components, Protein denaturation
97
T/F: Iodine is under Halogens.
True
98
Forms of Iodine
Tincture or Iodophores
99
This is the form of iodine that is used for antiseptics, and is composed of alcohol and iodine solutions.
Tincture
100
This is a form of iodine with an added neutral polymer carrier.
Iodophors
101
This form of iodine is preferrable, and must be diluted.
Iodophors
102
This halogen is one of the oldest and common disnifectants.
Chlorine
103
Chlorine is in the form of what, and is not used as sterilants?
Hypochlorite
104
Dilution for Chlorine
1:10 dilution of 5.25%
105
Water Sterilization is done through?
- Addition of Bleach
- Addition of Chlorine
- Collection for Water Testing
106
Addition of Chlorine is done with what, and where?
Copper Sulfate Pentahydrate, swimming pools and in drinking water
107
Addition of Bleach
2-3 drops in 1 liter of water for 30 minutes
108
What is added in collection for water testing?
Sodium Thiosulfate
109
This chemical method is rarely used, and has a bacteriostatic property.
Heavy Metals
110
MOA of Heavy Metals
Protein and enzyme inactivation
111
Mercury
Merthiolate
112
Silver
1% Silver Nitrate (Crede's Prophylaxis)
113
Copper
Copper Sulfate (anti-algae)
114
Heavy metals
- Mercury
- Sulfur
- Copper
115
MOA of Oxidizing agents
Oxidation of cellular components
116
Example of oxidizing agents
Hydrogen peroxide, Ozone
117
These refer to chemically substituted phenol compounds, less toxic and more effective.
Phenolic Compounds
118
MOA of Phenolic Compounds
Protein denaturation, cell membrane and enzyme inactivation
119
Examples of phenolic compounds
Ortho-phenylphenol and ortho-benzyl-para-chlorophenol
120
Uses of phenolic compounds
Hospital and institutional disinfection
121
This chemical method is effective against Gr (+), has a residual effect and is toxic.
Hexachlorophene
122
MOA of Hexachlorophene
interruption of electron transport, enzyme inhibition, membrane destruction
123
This is effective against Gr (+), and is not affected by organic compounds.
Chloroxylenol
124
MOA of Chloroxylenol
Cell wall disruption, enzyme inactivation
125
QUATS stands for?
Quaternary Ammonium Compounds
126
These are surface active agents which reduce surface tension, and is inactivated by organic compounds and hard water.
QUATS
127
MOA of QUATS
Protein denaturation, cell membrane destruction
128
Examples of QUATS
- Benzalkonium Cl (Zephiran)
- Cetylperidium Chloride
129
QUATS are resistant to?
Mycobacterium tuberculosis
130
These are used for mechanical action by rubbing and scrubbing.
Soap and Detergents
131
Soap and detergents possess antibacterial ingredients such as?
Triclocarbon or Triclosan
132
What is used to check effectiveness of physical methods?
Spore strips (placed before autoclaving)
133
Spore strips contain the?
endospore
134
Complete sterilization of spore strips is characterized by?
blackened spore strip
135
Effectiveness of Physical Methods
Hot-air oven
Bacillus subtilis var. niger
136
Effectiveness of Physical Methods
Ethylene gas
Bacillus subtilis var. globigii
137
Effectiveness of Physical Methods
Ionization Radiation
Bacillus pumilus
138
Effectiveness of Physical Methods
Autoclave
- Geobacillus/Bacillus stearothermophilus
139
Effectiveness of Chemical Methods
Determination of Phenol Coefficient
