microbiology ch 7 Flashcards
1
Q
What is sepsis?
A
Bacterial contamination
2
Q
What is asepsis?
A
Absence of significant contamination
3
Q
What do aseptic surgery techniques do?
A
Prevent the microbial contamination of wounds
4
Q
This is a term for bacterial contamination
A
Sepsis
5
Q
This is the absence of significant contamination
A
Asepsis
6
Q
These prevent the microbial contamination of wounds
A
Aseptic surgery techniques
7
Q
What is sterilization?
A
Removing and destroying all microbial life
8
Q
What is an example of commercial sterilization?
A
Killing Clostridium botulinum endospores from canned goods
9
Q
What is disinfection?
A
Destroying harmful microorganisms
10
Q
What is antisepsis?
A
Destroying harmful microorganisms from living tissue
11
Q
What is degerming?
A
The mechanical removal of microbes from a limited area
12
Q
What is sanitization?
A
Lowering microbial counts to safe levels
13
Q
What is biocide (germicide)?
A
Treatment that kills microbes
14
Q
What is bacteriostasis?
A
Inhibiting microbe growth
15
Q
Does bacteriostasis kill microbes?
A
No
16
Q
This is removing and destroying all microbial life
A
Sterilization
17
Q
An example of this is the killing of Clostridium botulinum endospores from canned goods
A
Commercial sterilization
18
Q
This is destroying harmful microorganisms
A
Disinfection
19
Q
This is destroying harmful microorganisms from living tissue
A
Antisepsis
20
Q
This is the mechanical removal of microbes from a limited area
A
Degerming
21
Q
This is lowering microbial counts to safe levels on eating utensils
A
Sanitization
22
Q
These are treatments that kill microbes
A
Germicides (biocides)
23
Q
This is the inhibition, but not killing, of microbes
A
Bacteriostasis
24
Q
What are four factors in the effectiveness of microbe control?
A
Number of microbes; environment; exposure time; microbial characteristics
25
Do most microbial controls work better in cold conditions?
No
26
Do resistant microbes/endospores require more time to kill?
Yes
27
The number of microbes, environmental conditions, time of exposure, and microbial characteristics all influence this
Effectiveness of microbial control efforts
28
What are the 3 main ways of killing/inhibiting microbes?
Altering membrane permeability; damaging proteins (enzymes); damaging nucleic acids
29
How does altering membrane permeability kill/inhibit microbes?
Damage to lipids/proteins of plasma membrane causes cellular contents to leak and interferes with cell growth
30
How does damaging a microbes' proteins/enzymes kill/inhibit it?
Chemicals disrupt the bonds that maintain the three-dimensional shape of proteins/enzymes
31
How does damaging nucleic acids kill/inhibit microbes?
Damage from heat, radiation, or chemicals can affect cell's ability to replicate and carry out normal metabolic functions
32
What does heat do to enzymes?
Denatures them
33
What is the thermal death point (TDP)?
The lowest temperature at which all cells in a liquid culture are killed in 10 minutes
34
What is the thermal death time (TDT)?
The minimum time for all bacteria in a liquid culture to be killed at a particular temperature
35
This denatures enzymes
Heat
36
This is the lowest temperature at which all cells in a liquid culture are killed in 10 minutes
Thermal death point (TDP)
37
This is the minimum time for all bacteria in a liquid culture to be killed at a particular temperature
Thermal death time (TDT)
38
What is decimal reduction time (DRT)?
Time to kill 90% of a specific population of bacteria at a given temperature
39
This is the time it takes to kill 90% of a specific population of bacteria at a given temperature
Decimal reduction time (DRT)
40
What does moist heat sterilization do to proteins?
Denatures and coagulates
41
What are two types of moist heat sterilization?
Boiling and free-flowing steam
42
This type of sterilization denatures and coagulates proteins
Moist heat sterilization
43
Boiling and free-flowing steam are two methods of this type of sterilization
Moist heat sterilization
44
What does an autoclave use to sterilize equipment?
Steam under pressure
45
What are typical autoclave conditions?
121 degrees at 15 psi for 15 minutes
46
Does an autoclave kill endospores?
Yes
47
What must steam do in an autoclave to be effective?
Contact the item's surface
48
What are used to indicate sterility when using an autoclave?
Test strips
49
Do large containers require shorter sterilization times in an autoclave?
No
50
What sterilization method uses steam under pressure?
Autoclave
51
In this sterilization method, pressurized steam kills all organisms and endospores
Autoclave
52
This sterilization method uses test strips to indicate sterility
Autoclave
53
In this sterilization method, smaller containers require shorter sterilization times
Autoclave
54
What does pasteurization involve?
High heat for a short time
55
What is a typical set of conditions for pasteurization?
72 degrees for 15 seconds
56
What organisms can survive high heat?
Thermoduric
57
This sterilization method uses high heat for short intervals to reduce spoilage organisms and pathogens
High-temperature short time (HTST) pasteurization
58
Thermoduric organisms can survive this
High heat
59
What are three methods of dry heat sterilization?
Flaming, incineration, and hot-air sterilization
60
What kills microbes in dry heat sterilization?
Oxidation
61
Flaming, incineration, and hot-air sterilization are three forms of this type of sterilization
Dry heat sterilization
62
This type of sterilization kills microbes by oxidation
Dry heat sterilization
63
This type of sterilization passes substances through a screenlike material
Filtration
64
What type of materials is the filtration method of sterilization used for?
Heat-sensitive materials
65
What size of microbes do high-efficiency particular air (HEPA) filters remove?
> 0.3 um in diameter
66
What size of microbes do membrane filters remove?
> 0.22 um
67
What are the smallest pore sizes available of microbe filtration?
0.01 um
68
What can 0.01 um filtration remove?
Viruses and large proteins
69
This sterilization method is used for heat-sensitive materials
Filtration
70
These can remove microbes >0.3 um in diameter
High-efficiency particular air (HEPA) filters
71
These can remove microbes >0.22 um in diameter
Membrane filters
72
Viruses and large proteins can be filtered through this pore size
0.01 um
73
What are three methods of low temperature microbial control?
Refrigeration, deep-freezing, and lyophilization (freeze-drying)
74
How does high pressure control microbes?
By denaturing proteins
75
How does desiccation control microbes?
The absence of water prevents metabolism
76
How does osmotic pressure control microbes?
Creates a hypertonic environment and plasmolysis
77
What effect does low temperature have on microbes?
Bacteriostatic effect
78
Which physical method of microbial control denatures proteins?
High pressure
79
Which physical method of microbial control prevents metabolism?
Desiccation
80
Which physical method of microbial control uses high concentrations of salts/sugars?
Osmotic pressure
81
Which physical method of microbial control creates a hypertonic environment and causes plasmolysis?
Osmotic pressure
82
What are three forms of radiation as microbial control?
Ionizing radiation, nonionizing radiation, and microwaves
83
How does ionizing radiation kill microbes?
Creates reactive hydroxyl radicals and causes lethal mutations in DNA
84
How does nonionizing radiation kill microbes?
By creating thymine dimers in DNA
85
How do microwaves kill microbes?
By heat
86
This method of radiation microbe control damages DNA by causing lethal mutations
Ionizing radiation
87
What are three types of ionizing radiation used to kill microbes?
X-rays, gamma rays, electron beams
88
This method of radiation microbe control damages DNA by creating thymine dimers
Nonionizing radiation
89
What type of nonionizing radiation is used to kill microbes?
Ultraviolet (260nm)
90
This type of radiation microbe control kills by heat and is not especially antimicrobial
Microwave
91
What are four factors in effective disinfection?
Concentration of disinfectant, presence of organic matter, pH, and time
92
How does organic matter affect disinfection?
By interfering with the mechanism of action
93
Does pH have a great effect on disinfectant's activity?
Yes
94
Is effectiveness of a disinfectant unrelated to its concentration?
No
95
Can organic material interfere with a disinfectant?
Yes
96
Is time a factor in disinfection?
Yes
97
What are two methods to evaluate a disinfectant?
Use-dilution test and disk-diffusion method
98
What does the use-dilution test for evaluating disinfectant involve?
Dipping metal cylinders in test bacteria and drying, then placing in disinfectant and transferring to culture media
99
In this disinfectant evaluation method, metal cylinders are dipped in bacteria then disinfected then transferred to culture media to determine whether bacteria survived treatment
Use-dilution test
100
What does the disk-diffusion method of evaluating disinfectant involve?
Soaking filter paper disks in a chemical and placing on a culture
101
In the disk-diffusion of evaluating disinfectant, what indicates an effective disinfectant?
Zone of inhibition around filter paper disk
102
What does the disk-diffusion method evaluate?
The efficacy of chemical disinfecting agents
103
In this method of disinfectant evaluation, filter paper disk are soaked in a chemical and placed on a culture medium
Disk-diffusion method
104
In the disk-diffusion method of disinfectant evaluation, does a smaller zone of inhibition indicate a more effective disinfectant?
No
105
How do phenols and phenolics control microbes?
By injuring lipids of plasma membranes, causing leakage
106
These chemicals kill microbes by injuring the plasma membrane and causing leakage
Phenols and phenolics
107
How are bisphenols structured?
Two phenol groups connected by a bridge
108
What are two examples of bisphenols?
Hexachlorophene and triclosan
109
How do bisphenols work?
By disrupting plasma membranes
110
These chemical disinfectants contain two phenol groups connected by a bridge
Bisphenols
111
Hexachlorophene and triclosan are two examples of this group of chemical disinfectants
Bisphenols
112
How do biguanides work?
By disrupting plasma membranes, especially in gram-positive bacteria
113
What are biguanides used in?
Surgical hand scrubs
114
What is an example of a biguanide?
Chlorhexidine
115
These chemical disinfectants include chlorhexidine and are used in surgical hand scrubs
Biguanides
116
This group of chemical disinfectants disrupts plasma membranes, and is especially effective against gram-positive bacteria
Biguanides
117
What are essential oils?
Mixtures of hydrocarbons extracted from plants
118
What have essential oils been used for historically?
Traditional medicine and food preservation
119
What is the microbial action of essential oils due to?
Phenolic and terpenes
120
Are essential oils stronger against gram-positive or negative bacteria?
Gram-positive bacteria
121
Have essential oils been studied for effectiveness against viruses?
No
122
These are mixtures of hydrocarbons extracted from plants
Essential oils
123
These have been used for centuries in traditional medicine and for preserving food
Essential oils
124
The microbial action of these is primarily due to phenolics and terpenes
Essential oils
125
These are stronger against gram-positive bacteria and have not yet been studied for their effectiveness against viruses
Essential oils
126
What are two halogens used in disinfectants?
Iodine and chlorine
127
What is an iodine tincture?
Solution in aqueous alcohol
128
What is iodophor?
Iodine combined with organic molecules for slow release
129
How do iodine disinfectants work?
By impairing protein synthesis and altering membranes
130
How do chlorine disinfectants work?
They are oxidizing agents that shut down cellular enzyme systems
131
What is chloramine?
Chlorine and ammonia
132
This is a solution of iodine in aqueous alcohol
Tincture
133
This is iodine combined with organic molecules for the slow release of iodine
Iodophor
134
This halogen impairs protein synthesis and alters membranes
Iodine
135
This halogen is an oxidizing agent
Chlorine
136
This halogen shuts down cellular enzyme systems
Chlorine
137
What is bleach?
Hypochlorous acid (HOCl)
138
What is chlorine + ammonia?
Chloramine
139
What is hypochlorous acid (HOCl) also known as?
Bleach
140
How do alcohols work as disinfectants?
Denature proteins and dissolve lipids
141
Can alcohols kill endospores?
No
142
Can alcohols kill enveloped viruses?
Yes
143
Can alcohols kill nonenveloped viruses?
No
144
What are two examples alcohols used as disinfectants?
Ethanol and isopropanol
145
Do ethanol and isopropanol require water to be more effective?
Yes
146
These disinfectants denature proteins, dissolve lipids, and require water to be more effective
Alcohols
147
These disinfectants have no effect on endospores and nonenveloped viruses
Alcohols
148
What does having oligodynamic action mean?
Very small amounts exert antimicrobial activity
149
How do heavy metals and their compounds work as disinfectants?
Denature proteins
150
What are four examples of heavy metals used as disinfectants?
Ag, Hg, Cu, Zn
151
What is silver nitrate used for?
Preventing opthalmia neonatorum
152
What is mercuric chloride used for?
Preventing mildew in paint
153
What is copper sulfate used for?
Algicide
154
What is zinc chloride used in?
Mouthwash
155
These disinfectants have oligodynamic action and denature proteins
Heavy metals and their compounds
156
This heavy metal disinfectant is used to prevent opthalmia neonatorum
Silver nitrate
157
This heavy metal disinfectant is added to paint to prevent mildew
Mercuric chloride
158
This heavy metal disinfectant is an algicide
Copper sulfate
159
This heavy metal disinfectant is found in mouthwash
Zinc chloride
160
How do surface-active agents work?
Decrease surface tension among molecules of liquid
161
What are the most common surface-active agents?
Soaps and detergents
162
What two properties does soap have as a disinfectant?
Degerming and emulsification
163
How do acid-anionic sanitizers work?
Anions react with plasma membrane
164
How do quaternary ammonium compounds (quats) work?
Cations are bactericidal, denature proteins, and disrupt plasma membrane
165
This group of disinfectants decrease surface tension among liquid molecules; the most common are soaps and detergents
Surface-active agents
166
This type of surface-active agent degerms and emulsifies
Soap
167
This type of surface-active agent has anions that react with the plasma membrane
Acid-anionic sanitizer
168
These surface-active agents have bactericidal cations, denature proteins, and disrupt plasma membranes
Quaternary ammonium compounds (quats)
169
What is sulfur dioxide used for?
Preventing wine spoilage
170
What three chemical food preservatives prevent molds in acidic foods?
Sorbic acid, benzoic acid, calcium propionate
171
Can our bodies easily metabolize chemical food preservatives?
Yes
172
How do nitrites and nitrates work in food preservation?
Preventing endospore germination
173
This chemical prevents wine spoilage
Sulfur dioxide
174
These are used for preserving specimens and in medical equipment
Aldehydes
175
These inhibit microbe metabolism, but our bodies easily metabolize them
Chemical food preservatives
176
These prevent endospore germination in foods
Nitrites and nitrates
177
What are bacteriocins?
Proteins produced by one bacterium that inhibits another
178
What are two antibiotics used to prevent cheese spoilage?
Nisin and natamycin (pimaricin)
179
These are proteins produced by one bacterium that inhibits another
Bacteriocins
180
These are two antibiotics that prevent the spoilage of cheese
Nisin and natamycin (pimaricin)
181
How do aldehydes work?
Inactivate proteins by cross-linking with functional groups
182
What are aldehydes used for?
Preserving specimens and in medical equipment
183
What are two examples of aldehydes
Formaldehyde and ortho-phthalaldehyde
184
What is one of the few liquid chemical sterilizing agents?
Glutaraldehyde
185
These inactivate proteins by cross-linking with functional groups
Aldehydes
186
This is one of the few liquid chemical sterilizing agents
Glutaraldehyde
187
These include formaldehyde and ortho-phthalaldehyde
Aldehydes
188
How does chemical sterilization work?
Gaseous sterilant causes alkylation and cross-links nucleic acids and proteins
189
What is alkylation?
Replacing hydrogen atoms of a chemical group with a free radical
190
What is chemical sterilization used for?
Heat-sensitive material
191
This process involves a gaseous sterilant causing alkylation and cross-linking nucleic acids and proteins
Chemical sterilization
192
What is plasma?
The fourth state of matter consisting of electrically excited gas
193
How does plasma work as a disinfectant?
Free radicals destroy microbes
194
What is plasma sterilization used to disinfect?
Tubular instruments
195
This is the fourth state of matter and consists of electrically excited gas
Plasma
196
This involves free radicals destroying microbes and is used for tubular instruments
Plasma sterilization
197
What is the process of supercritical fluids sterilization?
Substances are passed through a screenlike material
198
What type of materials are supercritical fluids used to disinfect?
Heat-sensitive materials
199
Does supercritical fluid sterilization combine chemical and physical methods?
Yes
200
This sterilization method compressed CO2, resulting in gaseous and liquid properties
Supercritical fluid sterilization
201
This sterilization method is used for medical implants
Supercritical fluid sterilization
202
In this sterilization method, chemical and physical methods are combined and substances are passed through a screenlike material
Supercritical fluid sterilization
203
What are peroxygens and other forms of oxygen used to sterilized?
Contaminated surfaces and food packaging
204
How do peroxygens/other oxygen forms work?
By ionizing water to create reactive hydroxyl radicals
205
What are three types of reactive hydroxyl radicals?
O3, H2O2, and peracetic acids (PAA)
206
What is PAA effective at killing?
Endospores
207
These are oxidizing agents that are used to sterilize contaminated surfaces and food packaging
Peroxygens and other forms of oxygen
208
Are peroxygens and other forms of oxygen oxidizing agents?
Yes
209
These chemical disinfectants ionize water to create reactive hydroxyl radicals O3, H2O2 and peracetic acid (PAA)
Peroxygens and other forms of oxygen
210
This reactive hydroxyl radical is effective on endospores
Peracetic acid (PAA)
211
Do biocides tend to be more effective against gram-positive or gram-negative bacteria?
Gram-positive bacteria
212
Mycobacteria, endospores, and protozoans' cysts and oocytes are very resistant to these
Disinfectants and antiseptics
213
Are nonenveloped viruses generally more resistant than enveloped viruses?
Yes
214
Are prions resistant?
Yes
215
These four types of microbes are very resistant to disinfectants and antiseptics
Mycobacteria, endospores, protozoan cysts and oocytes
