Brainscape's Knowledge GenomeTM

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


See full index

MCIM 224 > 14 Control of Microbes in the Environment (Midterm 2 up to here) > Flashcards

14 Control of Microbes in the Environment (Midterm 2 up to here) Flashcards

1
Q

Controlling microbes in the envir means…

a. ctrling microbes on surfaces
b. ctrling microbes inside an infected host
c. All of the above

A

a. ctrling microbes on surfaces

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

When talking about ctrling microbes, what can “control” mean? (3)

A
  1. KILLING of microbes on a surface
  2. Physical REMOVAL of microbes from a surface
  3. PREVENTING AN INCREASE in microbial numbers on a surface
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

T or F: Ctrling microbes means creating a sterile envir.

A

F

Not necessarily. It CAN also mean just reducing their numbers

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

What two types of methods are used for ctrling environmental microorganisms?

A
  1. Physical methods

2. Chemical methods

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

List three physical methods by which microbes can be ctrled.

A
  1. Heat
  2. Radiation
  3. Filtration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

List three chemical methods by which microbes can be ctrled

A
  1. Antiseptics
  2. Disinfectants
  3. Preservatives
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does heat do to microbes? (3)

A
  1. Denatures proteins
  2. Denatures DNA
  3. Melts lipids

–>Cell death

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

What kind of heat is best to use? Why?

A

Moist heat (not dry heat)

a. faster heat penetration
b. better protein denaturation (H2O helps disrupt chemical bonds)

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

What’re two advantages of using heat to ctrl microbes?

A
  1. Economical

2. Easy to ctrl and monitor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Give 4 examples of how heat can be used to ctrl microbe populations. Also, indicate what gets killed via each method.

A
  1. Boiling water (bacteria and viruses get killed; spores DO NOT get killed)
  2. Pressurized steam (via the autoclave) (sterility - everything gets killed)
  3. Pasteurization (does not kill all bacteria, does not kill spores)
  4. Commercial canning (everything but a few spores remain)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What’re two ways you can tell something has been autoclaved?

A
  1. Heat-sensitive autoclave TAPE changes colour

2. INDICATOR strips on autoclave pouches

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

What’re 4 good habits to have when handling autoclaved materials?

A
  1. Check package integrity
  2. Check expiry date
  3. Check indicator strip
  4. Treat inside of package as sterile; the outside as not
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How can you ensure that your autoclave is working properly (i.e. killing everything)?

A

Use a “Spore Strip” test to test whether the autoclave is killing spores or not. If so, then it’s working (since spores are hardest to kill). If not, the the autoclave isn’t working properly.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is pasteurization?

A

When MILD heat is used to REDUCE the number of bacteria

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

T or F: Pasteurization kills all bacteria, but not spores.

A

F

It doesn’t kill all the bacteria present, nor does it kill spores.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What temperature and time was utilized in Pasteur’s original method of pasteurization?

A

63ºC, 30 mins

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

What method of pasteurization is used today? Describe it.

A

HTST (High Temp, Short Time)

72ºC, 15 sec, followed by rapid cool down > less adverse effect on taste vs. Pasteur’s original method

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

What’s a less frequently-used method of pasteurization (in Can/USA, at least)? Describe it. What’s a disadvantage of it?

A

UHT (Ultra-High Temperature) treatment

140ºC for 2 seconds > get 6-9 mths of room temperature shelf life,

Disadvantage: Milk has a “cooked” flavour

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

What is commercial canning?

A

A form of heating that uses special conditions of time and temp so that both spoilage organisms AND spores are killed

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

How many spores is commercial canning expected to kill?

A

10^12 spores = high safety margin

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

What types of foods require less heating time and lower heating temps wrt commercial canning?

A
  1. Acidic foods
  2. High salt foods
    - ->Bacteria are more sensitive in these envirs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What types of foods require more heating time and high heating temps wrt commercial canning?

A
  1. High protein foods
  2. High fat foods
    - -> Bacteria are more protected in these envirs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

UHT treatment and commercial canning methods produce foods that’re commercially sterile. Differentiate b/w commercially sterile and true sterility.

A

True sterility involves the complete destruction of ALL microbes.

Commercial sterility is when food microbes/spores that can grow at storage temps are killed > prevents them from growing during storage and distribution

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

List three physical methods by which microbes can be ctrled.

A
  1. Heat
  2. Radiation
  3. Filtration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

List two types of radiation that can be used to ctrl microbial growth:

A
  1. Ultraviolet Light

2. Ionizing radiation

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

Germicidal lamps are a type of…

A

ultraviolet light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How does UV light (“germicidal lamps”) stop replication in microbes and cause mutations?

A

By causing DNA bases to “cross-link”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

About how long do microbes need to be exposed to UV light before they can be killed?

A

5-45 seconds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What’re 3 disadvantages of using UV light to ctrl microbial growth?

A
  1. Not ALL microbes are equally sensitive to UV light
  2. UV light damages the body (skin, eyes, etc.)
  3. UV light does not penetrate through liquids, plastics, glass, etc.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

UV light is useful for ____ and ____ sterilization only.

A

surface, air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What does ionizing radiation do?

A

It dislodges electrons from atoms, disrupts chemical bonds, and breaks DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

B/w UV radiation and ionizing radiation, which one has higher penetrative power?

A

Ionizing radiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Another term for “ionizing radiation” when applied to commercial uses is…

A

“cold sterilization”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

If a food is heat-sensitive, what can be used to sterilize it?

A

Ionizing radiation (“cold sterilization”)

[Can’t use any heating methods due to being heat sensitive]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

T or F: Putting a dry object into a microwave will sterilize it.

A

F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

How do microwaves heat up objects?

A

They excite WATER molecules, which then release energy as heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Can microwaves be used to kill microbes?

A

Yes, but only via heat, not the waves themselves (and the presence of water is req’d)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

T or F: The longer wavelengths of microwaves are better suited to kill microbes compared to UV rays.

A

F

Long wavelengths radiation cannot kill microbes since they’re low energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

List three physical methods by which microbes can be ctrled.

A
  1. Heat
  2. Radiation
  3. Filtration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

This method of microbial ctrl is used to physically remove microbes w/o killing them.

A

Filtration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What’re membrane filters?

A

Cellulose fiber w/ pores that range in size from 0.2 μm to 0.5 μm.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Can membrane filters trap bacteria?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Can membrane filters trap fungi?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Can membrane filters trap viruses?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

When are filters usually used to ctrl microbes?

A

When we’re dealing w/ heat sensitive-liquids or gases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

List three chemical methods by which microbes can be ctrled

A
  1. Antiseptics
  2. Disinfectants
    [Note: 1. and 2. are collectively known as “Germicides”]
  3. Preservatives
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Out of the three chemical methods by which microbes can be ctrled, which ones are used to KILL microbes on surfaces?

A
  1. Antiseptics

2. Disinfectants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Out of the three chemical methods by which microbes can be ctrled, which ones are used to inhibit the growth of microbes?

A
  1. Preservatives
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Why or why aren’t germicides and preservatives equivalent to antibiotics?

A

Germicides and preservatives are not SELECTIVELY TOXIC to specific types of microbes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What type of germicide is used on biological surfaces?

A

Antiseptics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What type of germicide is used on inanimate surfaces?

A

Disinfectants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

3 possible germicidal mechanisms of action:

A
  1. Denaturing and coagulating cellular proteins
  2. Dissolving lipids (e.g. in cell membranes)
  3. Oxidizing cellular macromolecules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q
  1. What are germicides always going to do for sure?

2. What CAN germicides do, but not always?

A
  1. Greatly reduce # of microbes on a surface (always)

2. Create a truly sterile surface (s. times; depends on agent)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What factors affect how well germicides will work? (5)

A
  1. Length of exposure
  2. Temp of envir
  3. Conc of germicide
  4. Presence of organic matter
  5. Number/type/special characteristics of microbes present
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What kind of temperatures are germicides more effective in?

A

Higher temps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

T or F: All microbes are killed at the same rate when germicides are used.

A

F (hence, time of exposure to germicides differ depending on the microbes being killed)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Higher concs of germicide is more effective at killing microbes. But what’s the downside?

A

Higher concs = More toxic effects (potentially)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

T or F: Bacteria that grow as biofilms are more resistant to germicides compared to the same bacteria as free cells.

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Because the presence of organic matter reduce germicide effectiveness, what “Golden Rule” should be followed?

A

“Clean before disinfecting”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Germicides are rated according to ______.

A

potency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

List the levels of germicides.

A
  1. High-level (“sterilants)
  2. Intermediate-level
  3. Low-level
62
Q

What do high-level germicides kill?

A

All microbes + spores

63
Q

What do intermediate-level germicides kill?

A

All microbes (not spores)

64
Q

What do low-level germicides kill?

A

Most vegetative bacteria (NOT Mycobacteria, spores, or some viruses)

65
Q

Why are the most potent germicides only used as disinfectants?

A

Bc they’re usually the most toxic to biological surfaces

66
Q

List the 3 risk categories of some medical devices (The Spaulding Classification System)

A
  1. Critical
  2. Semi-critical
  3. Non-critical
67
Q

What kind of medical items are considered “critical” when it comes to microbial ctrl?

A

Items that contact blood stream or sterile body tissues

68
Q

What kind of medical items are considered “semi-critical” when it comes to microbial ctrl?

A

Items that contact mucous membranes

69
Q

What kind of medical items are considered “non-critical” when it comes to microbial ctrl?

A

Items that only contact intact skin

70
Q

Needles would fall under which risk category?

A

Critical

71
Q

Stethoscopes would fall under which risk category?

A

Non-critical

72
Q

Mouthpieces would fall under which risk category?

A

Semi-critical

73
Q

Out of the three risk categories of some medical devices, which one would req higher potency germicidal agents?

A

Critical

74
Q

T or F: Skin can be sterilized after using soap for 5 minutes.

A

F

Skin cannot be truly sterilized.

75
Q

What’s the best way to prevent harmful microbes from getting on a physician’s hands?

A

Use a physical barrier (a rubber glove)

76
Q

List 8 categories of germicidal agents.

A
  1. Phenols
  2. Alcohols
  3. Peroxides
  4. Heavy metals
  5. Halogens
  6. Chlorhexidine
  7. Quaternary ammonium
    compounds (“Quats”)
  8. Alkylating agents
77
Q

Lister used WHAT as a germicide on the skin?

A

Carbolic acid (basically a phenol molecule)

78
Q

At higher concs, what side effects do phenols cause? (2)

A
  1. Skin irritation

2. Neurotoxicity

79
Q

What’re phenols used as today?

a. antiseptics
b. disinfectants

A

b. disinfectants (germicides for inanimate surfaces)

80
Q

Triclosan is an example of…

A

a chlorinated phenol

81
Q

What is triclosan’s MOA?

A

inhibits an enzyme needed for bacterial fatty acid synthesis

82
Q

The use of triclosan in WHAT was banned by the FDA?

A

antibacterial soaps

83
Q

What is the MOA of alcohols (in germicides)?

A
  1. Dissolves lipids

2. Denatures proteins

84
Q

What’re alcohol germicides effective against?

A

Bacteria, viruses, fungi

85
Q

What AREN’T alcohol germicides effective against?

A

Spores

86
Q

What’re alcohols used as?

a. antiseptics
b. disinfectants

A

a. antiseptics (alcohols are non-toxic and non-irritating)

87
Q

Why are alcohol germicides usually used as 70% solns in water? (2)

A
  1. Water aids in protein denaturing effect

2. Water slows the rate of alcohol evaporation

88
Q

What’s the most commonly used germicide for hand sanitation in healthcare?

A

Alcohols

89
Q

Bacteria located in ____ may survive after alcohol evaporates from the skin.

A

pores

90
Q

What kind of microbes are killed by peroxide germicides (such as H2O2)?

A

Anaerobic bacteria

91
Q

PerCept (R) is an example of…?

A

“Accelerated hydrogen peroxide”

92
Q

List 8 categories of germicidal agents.

A
  1. Phenols
  2. Alcohols
  3. Peroxides
  4. Heavy metals
  5. Halogens
  6. Chlorhexidine
  7. Quaternary ammonium
    compounds (“Quats”)
  8. Alkylating agents
93
Q

What’s the MOA of heavy metals when used as germicides?

A

They bind strongly to cellular proteins > inactivates cellular enzymes and inhibits membrane fns

94
Q

At low concs, heavy metals are used as…

a. antiseptics
b. disinfectants

A

a. antiseptics

95
Q

Fungal infections are usually treated w/ this heavy metal.

A

Selenium

96
Q

Mouthwashes usually contain this heavy metal for antiseptic purposes.

A

Zinc

97
Q

Burn wound ointments often contain this heavy metal.

A

Silver

98
Q

Heavy metals can be used on these types of surfaces to control microbial growth.

A

“Touch surfaces” (surfaces, such as light switches or grab bars, that’re constantly touched)

99
Q

MOA of halogens when used as germicides?

A

Denatures proteins

100
Q

Two most popular halogens used as germicides?

A
  1. Chlorine

2. Iodine

101
Q

Chlorine is mostly used in…

a. antiseptics
b. disinfectants

A

b. disinfectants

102
Q

What product includes chlorine in the form of sodium hypochlorite?

A

Household bleach (Javex)

103
Q

What concentration of chlorine is often used to treat drinking water?

A

0.5-1.0 ppm

104
Q

Disadvantages of using chlorine as a germicide? (2)

A
  1. Inactivated by organic matter

2. Poor long term stability

105
Q

Iodine is often useful as…

a. an antiseptic
b. a disinfectant

A

a. an antiseptic

106
Q

Name two types of germicidal preparations that iodine is often part of? What is each composed of?

A
  1. Tincture (2% iodine + 70% alcohol)

2. Iodophore (iodine + a hydrocarbon carrier)

107
Q

What’s the advantage of tinctures (2% iodine + 70% alcohol)?

A

Combined effect of TWO antiseptics

108
Q

What’s the point of the hydrocarbon carrier in iodophores (iodine + a hydrocarbon carrier)?

A

The carrier slows and prolongs the release of iodine

109
Q

Betadine (TM) is an example of what?

A

An iodophore (iodine + polyvinylpyrrolidone, a hydrocarbon carrier)

110
Q

MOA of chlorhexidine (germicide)?

A
  1. Disrupts membranes

2. Denatures proteins

111
Q

Chlorhexidine is used as…

a. an antiseptic
b. a disinfectant

A

a. an antiseptic

112
Q

This germicide is one of three antiseptics on the “WHO Essential Medicines List”

A

Chlorhexidine

113
Q

What is chlorhexidine usually used for? (2)

A
  1. Coating catheters and implanted devices, etc.

2. Antiseptic skin creams and wipes

114
Q

MOA of quaternary ammonium cmpnds (“Quats”)?

A

Dissolves lipids in cell membranes

115
Q

What are quaternary ammonium cmpnds?

A

Detergents made of 4 organic gps attached to a nitrogen atom

116
Q

Quaternary ammonium cmpnds have good activity against everything except these.

A
  1. Mycobacteria

2. Spores

117
Q

Name one product in which Quats are used.

A

Antiseptic mouthwashes

118
Q

MOA of alkylating agent germicides?

A

Cross-links and denatures cellular macromolecules

119
Q

Alkylating agents are used as…

a. antiseptics
b. disinfectants

A

b. disinfectants

120
Q

If given long exposure times (5-10 hours), alkylating agents can act as what?

A

High-level germicides (sterilants)

121
Q

Name a liquid type of alkylating agent.

A

Glutaraldehyde

122
Q

Name two gaseous types of alkylating agents.

A
  1. Ethylene oxide

2. Propylene oxide

123
Q

Advantage of glutaraldehyde?

A

It has good action in the presence of organic material

124
Q

How long does it take for glutaraldehyde to kill vegetative bacteria?

A

10 mins

125
Q

How long does it take for glutaraldehyde to kill spores?

A

10 hours

126
Q

What’s the advantage of using gaseous alkylating agents, such as ethylene oxide or propylene oxide?

A

They allow for penetration of alkylating agent into hard-to-reach areas

127
Q

What’re three disadvantages of using gaseous alkylating agents (e.g. ethylene or propylene oxide)?

A
  1. Very toxic
  2. Explosive
  3. Carcinogenic
128
Q

Germicide “failure” is often due to… (4)

A
  1. not following proper procedures and manufacturer instructions
  2. inadequate cleaning (i.e. failing to remove organic material first)
  3. Wrong agent for situation
  4. Germicidal product itself is contaminated
129
Q

T or F: Germicides can be used as a substitute for proper preventative procedures.

A

F

130
Q

Germicidal chemicals play an important role in maintaining a safe working environment when used _____ and _____.

A

regularly, properly

131
Q

The antibacterial products available to consumers usually have _____ antibacterial properties.

Why?

A

modest/low

To avoid toxicity

132
Q

What determines whether or not antimicrobial consumer products are beneficial?

A

If they are safer and more effective than regular soap and water

133
Q

T or F: If germicidal chemicals are shown to kill microbes in the lab, then this means that they can reduce the spread of infectious disease in real-life (compared to non-germicides)

A

F

134
Q

A product is considered to be microbiologically “spoiled” if…(3)

A
  1. Microbes w/ pathogenic potential are present
  2. Toxic microbial metabolites (e.g. LPS) are present
  3. Microbial growth has caused deterioration of the product
135
Q

What is the main requirement for chemicals that’re to be used as preservatives?

What’re 2 other requirements for preservatives?

A
  1. They must be completely NON-TOXIC after repeated contact and/or ingestion
  2. No interactions w/ other product ingredients
  3. Effective against wide range of microbes
136
Q

Preservatives can either…

A
  1. kill microbes directly

2. alter the envir so that microbes can’t grow (more common)

137
Q

What’re the most common preservatives used in pharmaceuticals?

A

Standard germicidal chemicals at LOW CONC

138
Q

Preservatives used in foods must be classified by the US FDA as…

A

GRAS

Generally Recognized As Safe (i.e. not toxic after ingestion)

139
Q

What is the MOA of organic acids when they’re used as preservatives in foods? (2)

A
  1. They interfere w/ proper fn’ing of cell membranes

2. They create an acidic envir which inhibits growth

140
Q

What is the MOA of sodium nitrite when used as preservatives in foods?

A

Inhibits growth of Clostridium > reduces risk of botulism due to C. botulinum

141
Q

What is the MOA of high sugar/salt when used as preservatives in foods?

A

Reduces water availability

142
Q

Name three spices/herbs that have a strong antimicrobial effect.

A
  1. Cinnamon
  2. Cloves
  3. Mustard
143
Q

Name three spices/herbs that have a medium antimicrobial effect.

A
  1. Coriander
  2. Cumin
  3. Thyme
144
Q

Name three spices that have a weak antimicrobial effect.

A
  1. Black pepper
  2. Red pepper
  3. Ginger
145
Q

What spice has been found to be effective in vitro against hospital-associated strains of Clostridium difficile?

A

Tumeric

146
Q

Name 2 types of “biological” control agents that are used as food preservatives.

A
  1. Bacteriophage

2. Bacteriocins

147
Q

What’re bacteriocins?

A

Small peptides made by some bacteria that KILL OTHER BACTERIA by forming holes in plasma membranes

148
Q

What’s the ONLY bacteriocin approved as a food preservative? What bacteria is it toxic to?

A

Nisin

It’s toxic to Clostridium botulinum and some other Gram positive bacteria

149
Q

In “Modified-Atmosphere Packaging” of foods, what is normal air replaced with to prevent aerobe growth?

A

Nitrogen/CO2 mixture

150
Q

In “Modified-Atmosphere Packaging” of foods, what is normal air replaced with to prevent anaerobe growth?

A

90% O2 + 10% nitrogen mixture

MCIM 224 (25 decks)

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