Brainscape's Knowledge GenomeTM

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


See full index

Clinical Bacteriology (Laboratory) > Control of Microbial Growth: Explore decontamination and selective toxicity (Labster Lab Manual | M) > Flashcards

Control of Microbial Growth: Explore decontamination and selective toxicity (Labster Lab Manual | M) Flashcards

1
Q

What is microbial load?

A

The # or infection pathogens on an item

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

For objects or items having microbial load, what should be done?

A

In these situations, these needs to be carefully managed

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

In pt care scenarios, what should be done to control the spread of infection?

A

Careful cleaning procedures

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

In cases where potentially contaminated items are invasively introduced to soft tissue or the vascular system, what should be done?

A

Sterilization techniques are used to prevent infection transmission

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

When is less stringent decontamination techniques used?

A

These are used to keep living organisms safe from pathogenic harm

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

What is Spaulding classification scheme?

A

It was devised as a logical way to determine the disinfection schemes required for items used during pt care

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

True or False.

The Spaulding classification scheme still remains the clearest and most concise way of assessing an object’s infection risk despite being over half a century old

A

True

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

What is the importance of Spaulding classification scheme?

A

It is important as it ensures all items receive an appropriate lvl of decontamination w/out overburdening an infection control system

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

Objects (via the application of Spaulding classification scheme) are split into how many categories?

A

3

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

Objects (via the application of Spaulding classification scheme) are split into 3 categories depending on what?

A

Depending on their normal use

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the 3 categories (via the application of Spaulding classification scheme)?

A

1) Critical
2) Semi critical
3) Noncritical

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

What are critical items (as per Spaulding classification scheme | in terms of infection transmission)?

A

These items pose the highest threat of infection transmission

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

What are noncritical items (as per Spaulding classification scheme | in terms of infection transmission)?

A

These items pose the lowest threat of infection transmission

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

Items from different categories / classes (as per Spaulding classification scheme) go through different what?

A

Different decontamination processes

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

What are critical items?

A

These are objects that are designed to contact normally sterile tissue (like blood) or enter the vascular system

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

True or False.

Any microbial load on such an object could introduce an infection to an otherwise healthy pt

A

True

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

What should be done to critical items?

A

These items must be sterilized (if heat resistant)

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

What is the preferred method of sterilizing critical items (if heat resistant)?

A

Steam methods

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

What is the preferred method of sterilizing critical items (if heat sensitive)?

A

Alternate method

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

What are the examples of critical items?

A

1) Forceps
2) Scalpels
3) Bone saws

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

What normally sterile tissue are normally contacted w/ critical items?

A

Blood

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

What are semicritical items?

A

1) These items ordinarily make contact only w/ mucous membranes or the skin
2) They don’t enter open wounds or penetrate soft tissues

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

Does semicritical items enter open wounds or penetrate soft tissues?

A

No, they do not

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

What should be done to reusable semicritical items?

A

These items should be steam-sterilized (if the item can withstand such treatment)

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

What is the min acceptable process for reusable semicritical items?

A

High-level disinfection

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

What should be done to semicritical items prior to further decontamination processing?

A

These items should be thoroughly cleaned to remove debris and soil

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

What are the examples of semicritical items?

A

1) Endospores and speculums
2) Dental mirrors and other simple hand tools
3) Reusable trays for making tooth impressions

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

What are noncritical items?

A

These items only ever contact intact skin and do not touch mucous membranes

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

Does noncritical items pose moderate infection transmission risk?

A

No, it poses low infection transmission risk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What level of disinfection is routinely required for noncritical items?

A

Low-level disinfection

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

What are the examples of noncritical items?

A

1) Stethoscope
2) Bedpan
3) Walking crutches

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

What is selective toxicity (in microbiology)?

A

It is the idea that a chemical agent or drug can exert a toxic effect on a pathogen and leave the infected host organism unharmed

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

What is the action of antimicrobial drugs such as penicillin, metronidazole, and chloramphenicol?

A

These antimicrobial drugs interact w/ cellular components that are only found in their target organism w/c allows the agent to exert its effect only on the cells that carry the target component

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

What is an example of a target component being acted upon by certain antimicrobial drugs?

A

An enzyme involved in building a cell wall or a sp metabolic ribozyme

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

When and what is the cause of microorganisms becoming resistant?

A

As microorganisms mutate, changes to the target component may occur meaning the drug may no longer exert its toxic effect

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

If the antimicrobial agent is present and actively killing off unwanted competing sister cells at the time, can the mutated cell may have a survival advantage?

A

Yes

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

What is the cause of antimicrobial resistance?

A

The proliferation of mutant cells

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

When can the action of antimicrobial resistance be worst?

A

If the resistant gene is transferred to other microorganisms

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

Answer the ff questions:

a) Is disinfectant selectively toxic?
b) What are the targets of disinfectant?

A

a) No

b) All proteins, lipids, organic compounds, etc., no sp target

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Answer the ff questions:

a) Is antiseptic selectively toxic?
b) What are the targets of antiseptic?

A

a) No

b) All proteins, lipids, organic compounds, etc., however safe for external use on skin

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

Answer the ff questions:

a) Is antimicrobial selectively toxic?
b) What are the targets of antimicrobial?

A

a) Yes

b) Binds or is activated by a sp target found only in target organism. Safe for internal administration

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

Is antiseptic not safe for external use on skin?

A

No, because it is safe for external use on skin

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

Is antimicrobial safe for internal administration?

A

Yes

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

What are the principles of sterilization?

A

1) It is a type of decontamination where no microbial load remains on an item
2) There are 0 bacteria, fungi, spores, or even proteins present to transmit infection

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

What is the highest lvl of decontamination an object can receive?

A

Sterilization

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

In healthcare settings, what is recommended to be done to critical and semicritical items?

A

These items should be sterilized

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What are the most common sterilization techniques in the lab?

A

1) Wet Heat (steam)
2) Dry Heat
3) Chemical
4) Irradiation

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

What is the other term for wet heat (steam)?

A

Steam sterilization

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

What is steam sterilization considered and what is its principle?

A

It is the gold std method of inactivating all organic pathogens including spores and prion proteins

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

What are the components (or organisms that are included) that are inactivated by steam sterilization?

A

Including spores and prion proteins

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

What should be done to some items that are heat or pressure-sensitive (in terms of sterilization)?

A

These items should be sterilized using an alternative appropriate methodology

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

What sterilization technique is commonly used for metal tools and heat resistant plastics?

A

Steam sterilization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What machine is used in steam sterilization?

A

Autoclave

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

What principle is an alternative to wet heat sterilization?

A

Baking objects in an oven where an object may be intolerant of moist conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

True or false.

The temp and cycle time of dry heat sterilization is higher than an autoclave

A

True

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

What is the temp and cycle time in dry heat sterilization?

A

Temp: 160 - 190 DC

Cycle time: up to 2 hrs

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

In dry heat sterilization, give an example of how an object may be intolerant of moist conditions?

A

Due to corrosion

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

What is the principle of action of chemical sterilants?

A

These react w/ proteins and membranes to destroy organic pathogens

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

What type of sterilants can also be used to achieve high-lvl disinfection?

A

Liquid sterilants

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

What are the methods that eliminate the need for a high temp?

A

The use of chemical sterilants and liquid sterilants

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

Chemical and liquid sterilants can be a useful alternative to what techniques?

A

To wet and dry heat techniques

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What is the principle of ethylene oxide chambers (for chemical sterilization)?

A

It applies the use of toxic ethylene gas to kill organic pathogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

At what objects can the principle of action of ethylene oxide chambers useful?

A

Useful for:

1) moisture and
2) heat-sensitive objects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What are the effects of the byproducts of the principle of action of ethylene oxide chambers?

A

The byproducts of the process of ethylene oxide chambers are very environmentally damaging, carcinogenic, and explosive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What is the length of time of long degassing times (for chemical sterilization)?

A

< 24 hrs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

The principle of long degassing times (for ethylene oxide chambers) is reserved for what?

A

Long degassing times alongside toxicity issues is reserved for objects where no other techniques can be used

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What are the examples of liquid sterilants?

A

1) Paracetic acid

2) Glutaraldehyde

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

What is the requirement for objects to be acted upon by liquid sterilants?

A

The objects are required to be completely immersed for a verified period of time to achieve sterilization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

What are the results if metals are in acid for a prolonged period of time?

A

1) It can cause corrosion

2) Glutaraldehyde will bind blood and proteins irreversibly to the surface of a processed obj

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

What are the 2 types of irradiation (sterilization technique)?

A

1) Non-ionizing radiation

2) High energy ionizing radiation techniques

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

What is the principle of the 2 types of sterilization via irradiation?

A

These inactivates microorganisms by damaging their DNA either directly or indirectly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

How are the 2 types of sterilization via irradiation employed?

A

Microorganisms are inactivated by damaging their DNA either directly or indirectly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What is used in non-ionizing radiation?

A

Ultraviolet (UV) light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

Compare non-ionizing radiation and high energy ionizing radiation techniques

A

Non-ionizing radiation is a lower energy process than high energy ionization radiation techniques

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

What is used in high energy ionizing radiation techniques?

A

Gamma rays or X-rays

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

Can non-ionizing UV radiation penetrate objects and can be used to sterilize surfaces?

A

No, non-ionizing UV radiation can’t penetrate objs but it can only be used to sterilize surfaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

How are microbes inactivated via the use of UV bulb (or UV light)?

A

Any microbes in the direct sightline of the UV bulb will be inactivated due to DNA damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

Is UV light considered carcinogen to humans and other animals? If yes, why? If no, why not?

A

UV light is considered a carcinogen to humans and other animals because its action is inactivation of microbes due to DNA damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

What is the result if skin cell (of humans) are damaged (or exposed) by solar UV irradiation?

A

The skin cell DNA damaged by solar UV irradiation is linked to development of skin cancers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

Irradiation techniques are operated at what temps?

A

At low temps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

Are irradiation techniques useful for heat-sensitive items? Why or why not?

A

Yes, because irradiation techniques operate at low temps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

What are the 2 types of indicators to determine if the sterilization run was successful?

A

1) Biological indicators

2) Chemical indicators

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

What are biological indicators and what is its principle (in terms of indication of a successful sterilization run)?

A

These are often small sxs of microorganism spores that should be inactivated if the sterilization method is successful

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

What component of a microorganism is used as a biological indicator (for a sterilization run)?

A

Spores of microorganisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

What should be done to the spores (used as biological indicators) after a sterilization run?

A

The spores are plated onto the growth medium and checked to see if they produce new cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

Provide a result (after a sterilization run) for the use of biological indicator and provide its interpretation

A

If spores that are putted onto the growth medium does not grow new cells or fails to grow, it is an indication that the sterilization run done is good and successful

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

What are the principles of use of chemical indicators (for determining if a sterilization run was successful)?

A

1) These indicators take the form of color-changing compounds that react if the sterilization conditions are met for the right length of time
2) These can include ink patches on sterilization pouches that change from pink / yellow to brown / black
3) adhesive tape that does the same and can be applied to bottles and paper-wrapped parcels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

When does color-changing compounds formed (for chemical indicators | for a sterilization run)?

A

If the sterilization conditions are met for the right length of time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

What is the principle of color change of ink patches (present on sterilization pouches)?

A

The ink patches present change from pink / yellow to brown / black

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

Where can adhesive tape be used?

A

It can be applied to bottles and paper-wrapped parcels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

What is the aim of all disinfection processes?

A

To reduce the microbial load of a processed item

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

What are the 3 lvls (to see how effective is the disinfection method done) pf disinfection?

A

1) High-level disinfection (HLD)
2) Intermediate-level disinfection (ILD)
3) Low-level disinfection (LLD)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

What is the goal of HLD?

A

To kill all but the most resistant of spores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

What is not killed via HLD?

A

The most resistant of spores

95
Q

What are the techniques that can be used in HLD?

A

Either heat or liquid immersion techniques (depending on the item to be processed)

96
Q

What should be done for liquid immersion technique (for HLD) to be successful?

A

Objs must be completely immersed in a verified high-lvl disinfectant solution for a predetermined period of time

97
Q

Provide examples of application of liquid immersion technique (for HLD)

A

1) 0.2 % glutaraldehyde solution can be used for up to 45 mins
2) 0.2 % peracetic acid solution can be used for 12 mins

98
Q

What is the result if there is a long contact time bet metal objs and acidic solutions?

A

It can cause corrosion

99
Q

What is pasteurization?

A

The process of heat processing for HLD

100
Q

What is the principle of action of ILD?

A

Most bacteria and fungi are inactivated including slow-growing Mycobacterium tuberculosis, however, some infectious spores may remain after processing

101
Q

Can infectious spores still remain after ILD?

A

Yes

102
Q

What are the examples of intermediate (occasionally low) lvl disinfectants?

A

1) Bleach

2) Alcohols

103
Q

What are the 2 main types of bleach?

A

1) Oxygen-based bleaches

2) Chlorine-based bleaches

104
Q

What is the main active ingredient used by oxygen-based bleaches?

A

Hydrogen peroxide

105
Q

What are used by chlorine-based bleaches?

A

Chlorine liberating compounds like sodium hypochlorite to do the cleaning

106
Q

What is the result if oxygen-based and chlorine-based bleaches are combined?

A

It can result in large volumes of chlorine gas being quickly released

107
Q

What is the result if oxygen-based and chlorine-based bleaches are mixed in a small enclosed space (like bathroom)?

A

It can kill a person

108
Q

Are people (probably the maintenance) advised to mix cleaning mats?

A

No, because adverse effects may happen if done

109
Q

What is LLD?

A

It is the most basic form of disinfection

110
Q

What is the other terms (sometimes) for LLD?

A

Sanitization

111
Q

What is the principle of action of LLD?

A

Many bacteria are inactivated but M. tuberculosis may survive as may some fungi and spores

112
Q

What bacteria may survive from LLD?

A

M. tuberculosis

113
Q

What other microorganisms aside from bacteria may survive from LLD?

A

Fungi

114
Q

What component of bacteria or fungi may survive from LLD?

A

Spores

115
Q

What is the principle of cleaning?

A

It is the simple removal of surface soil and debris from an object (like doing the washing up)

116
Q

What is the action of surface soil?

A

It can impede the ingress of steam or chemical sterilants, making sterilization process ineffective

117
Q

Simple cleaning serves as what?

A

It serves as the foundation for all other decontamination processes

118
Q

True or False.

Washing items in water and detergent can not be a simple and effective technique

A

False, because washing items in H2O and detergent can be a simple and effective technique

119
Q

If enzymes are used during disinfection, what temp is used?

A

Lower temp

120
Q

Why washing up gloves are important?

A

Because of the presence of enzymes in biological detergents

121
Q

Can biological dish soap wreak havoc on the skin? Why or why not?

A

Yes, because of the presence of enzymes

122
Q

Answer the ff questions:

Given agent (disinfectant): Glutaraldehyde

a) What is the disinfection lvl?
b) What are the comments?

A

a) High
b) 0.2 % concentration required for HLD. Can irreversibly bind proteins to the surface of processed objs, thorough washing required before sterilant treatment

123
Q

Answer the ff questions:

Given agent (disinfectant): Peracetic acid

a) What is the disinfection lvl?
b) What are the comments?

A

a) High to intermediate
b) 0.2 % concentration required for HLD. Corrosion of metal objs can occur w/ long contact time. Environmentally safe waste produced after processing

124
Q

Answer the ff questions:

Given agent (disinfectant): Bleach

a) What is the disinfection lvl?
b) What are the comments?

A

a) Intermediate to low
b) 10 % concentration required. 2 types of bleach: chlorine (hypochlorite containing) and peroxide. Both peroxide and chlorine bleaches can corrode metal objs if left in contact for too long. Can irritate skin and mucous membranes

125
Q

Answer the ff questions:

Given agent (disinfectant): Alcohol (e.g. isopropanol)

a) What is the disinfection lvl?
b) What are the comments?

A

a) Intermediate
b) Used on hard surfaces as a disinfectant or on the skin as an antiseptic. Greater than 70 % v/v solution required. Denatures cell membranes and dehydrates cells

126
Q

Answer the ff questions:

Given agent (disinfectant): Iodophor

a) What is the disinfection lvl?
b) What are the comments?

A

a) Low
b) Iodine containing. Used at 0.1 - 0.2 % concentration. Some iodine-containing disinfectants can also be used as antiseptic agents

127
Q

Answer the ff questions:

Given agent (disinfectant): Detergent (bio or non-bio)

a) What is the disinfection lvl?
b) What are the comments?

A

a) Basic cleaning

b) Biological detergent contains enzymes, non-biological does not. Used to remove soil and surface debris from items

128
Q

What is the required concentration of glutaraldehyde for HLD?

A

0.2 % concentration

129
Q

What disinfecting agent can irritate skin and mucous membranes?

A

Glutaraldehyde

130
Q

What is the required concentration of peracetic acid for HLD?

A

0.2 % concentration

131
Q

What is the required concentration of bleach?

A

10 % concentration

132
Q

What are the 2 types of bleach?

A

1) Chlorine

2) Peroxide

133
Q

What is the component of chlorine bleach?

A

Hypochlorite

134
Q

What types of bleach can corrode metal objs (if left in contact for too long)?

A

Both peroxide and chlorine bleaches

135
Q

What disinfecting agent can irritate skin and mucous membranes?

A

Bleach

136
Q

What disinfecting agent can be used as a disinfectant or antiseptic on the skin?

A

Alcohol (e.g. isopropanol)

137
Q

What is the required % in v/v of alcohol?

A

Greater than 70 % v/v solution

138
Q

What disinfecting agent can denature cell membrane and dehydrates cells?

A

Alcohol (e.g. isopropanol)

139
Q

What disinfecting agent contains iodine?

A

Iodophor

140
Q

Iodophor is used at what concentration?

A

At 0.1 % - 0.2 % concentration

141
Q

Can some iodine-containing disinfectants also be used as antiseptic agents?

A

Yes

142
Q

What are the 2 types of detergent?

A

1) Biological

2) Non-biological

143
Q

What type of detergent contains enzymes?

A

Biological detergent

144
Q

What type of detergent does not contain enzymes?

A

Non-biological

145
Q

What disinfecting agent is used to remove soil and surface debris from items?

A

Detergent

146
Q

What is the principle of antisepsis?

A

It is the process of reducing the antimicrobial load on skin to prevent the spread of infection

147
Q

When are antiseptics used?

A

Cleansing of the skin’s microbial flora prior to an operation

148
Q

What antiseptic agent can be used prior to an operation?

A

Iodine solution

149
Q

What is the action of antimicrobial mouthwash (as an antiseptic agent)?

A

To prevent infection following a tooth extraction

150
Q

What are the examples of antiseptic agents?

A

1) Clorhexidine
2) Iodophor
3) Alcohol (e.g. isopropanol)

151
Q

Can some disinfecting agents be also used as an antiseptic? How are these disinfecting agents used as antiseptics?

A

Yes, at lower concentration

152
Q

Answer the ff questions:

Given antiseptic agent: Clorhexidine

a) What is the preparation?
b) What are the examples of use?

A

a) 2 % or 4 % solution

b) Prophylactic mouthwash against oral infection or helping to control existing infection

153
Q

Answer the ff questions:

Given antiseptic agent: Iodophor

a) What is the preparation?
b) What are the examples of use?

A

a) 10 % active iodine

b) Pre-operative treatment for skin prior to surgery

154
Q

Answer the ff questions:

Given antiseptic agent: Alcohol (e.g. isopropanol)

a) What is the preparation?
b) What are the examples of use?

A

a) ~ 70 %

b) Cleansing of wounds and grazes prior to dressing, cleansing of skin prior to injection

155
Q

What are the uses of prophylactic mouthwash (as an antiseptic agent)?

A

1) Against oral infection or 2) helping to control existing infection

156
Q

What is the use of iodophor (as an antiseptic agent)?

A

Pre-operative treatment for skin prior to surgery

157
Q

What are the uses of alcohol (e.g. isopropanol) (as an antiseptic agent)?

A

1) Cleansing of wounds and grazes prior to dressing

2) Cleaning of skin prior to injection

158
Q

What is the principle of action of antibiotics?

A

These are type of antimicrobial that are effective in treating bacterial infections

159
Q

What is the principle of the term ‘antimicrobial’?

A

It is a term used to cover many different compounds that can halt the growth of microbial cells

160
Q

Can antimicrobial compounds be non-selective?

A

Yes

161
Q

What are the antimicrobial compounds that can be non-selective?

A

1) Disinfectants

2) Sterilants

162
Q

Can antimicrobial compounds be selectively toxic?

A

Yes

163
Q

What is the principle of action of antimicrobial compounds being selectively toxic?

A

They target a sp type of microorganism

164
Q

What are the terms used for non-selective antimicrobials?

A

They’re loosely termed as:

1) Sterilants
2) Disinfectants
3) Antiseptics

165
Q

What are the 3 types of antimicrobial?

A

1) Sterilant
2) Disinfectant
3) Antiseptic

166
Q

Answer the ff questions:

Given type of antimicrobial: Sterilant

a) What or how is the efficacy employed?
b) What its intended uses?

A

a) Inactivates all living organisms

b) To eliminate all potential pathogenic spp. Used on inanimate objs only

167
Q

Answer the ff questions:

Given type of antimicrobial: Disinfectant

a) What or how is the efficacy employed?
b) What its intended uses?

A

a) Inactivates most organisms, but spores can survive

b) To reduce infection risk, used on inanimate objs

168
Q

Answer the ff questions:

Given type of antimicrobial: Antiseptic

a) What or how is the efficacy employed?
b) What its intended uses?

A

a) Reduces microbial load, varied efficacy

b) To reduce microbial load on skin surface and around wounds. Used on living organisms

169
Q

What are the intended uses of sterilant?

A

1) To eliminate all potential pathogenic spp

2) Used on inanimate objs only

170
Q

What are the intended uses of disinfectant?

A

1) To reduce infection risk

2) Used on inanimate objs

171
Q

What are the intended uses of antiseptic?

A

1) To reduce the microbial load on skin surface and around wounds
2) Used on living organisms

172
Q

Among the 3 types of antimicrobial agents, what is the only agent that is used on living organisms?

A

Antiseptic

173
Q

What are the examples of selective agents (or antimicrobials)?

A

1) Antibiotic drugs

2) Antifungal drugs

174
Q

What is the intended use of antibiotic and antifungal drugs?

A

For systemic use

175
Q

Selective agents (or antimicrobials) only interact to what?

A

To components found only in the target microorganism

176
Q

What is the result if the target of a sp antimicrobial is not expressed in a particular microorganism or if the target has become altered?

A

The drug will not exert an effect on that organism

177
Q

What are the examples of antimicrobial agents?

A

1) Penicillin
2) Clindamycin
3) Metronidazole
4) Mebendazole
5) Acyclovir

178
Q

Answer the ff questions:

Given antimicrobial agent: Penicillin

a) What is the type of antimicrobial?
b) What are the target organisms?
c) What are the toxic mechanisms employed by the antimicrobial agent?

A

a) Antibiotic
b) Gram (+) bacteria
c) Inactivates key transpeptidase enzyme in cell wall manufacture

178
Q

Answer the ff questions:

Given antimicrobial agent: Penicillin

a) What is the type of antimicrobial?
b) What are the target organisms?
c) What are the toxic mechanisms employed by the antimicrobial agent?

A

a) Antibiotic
b) Gram (+) bacteria
c) Inactivates key transpeptidase enzyme in cell wall manufacture

179
Q

Answer the ff questions:

Given antimicrobial agent: Clindamycin

a) What is the type of antimicrobial?
b) What are the target organisms?
c) What are the toxic mechanisms employed by the antimicrobial agent?

A

a) Antibiotic
b) Most bacteria
c) Interferes w/ protein translation by binding to ribosome

180
Q

Answer the ff questions:

Given antimicrobial agent: Metronidazole

a) What is the type of antimicrobial?
b) What are the target organisms?
c) What are the toxic mechanisms employed by the antimicrobial agent?

A

a) Antibiotic / Antifungal
b) Many bacteria and fungi
c) Activated only in microbial cells then causes irreparable DNA damage

181
Q

Answer the ff questions:

Given antimicrobial agent: Mebendazole

a) What is the type of antimicrobial?
b) What are the target organisms?
c) What are the toxic mechanisms employed by the antimicrobial agent?

A

a) Antihelminthic
b) Parasitic pinworms
c) Binds key cytoskeletal enzyme preventing worm growth and replication

182
Q

Answer the ff questions:

Given antimicrobial agent: Acyclovir

a) What is the type of antimicrobial?
b) What are the target organisms?
c) What are the toxic mechanisms employed by the antimicrobial agent?

A

a) Antiviral
b) Herpes virus
c) Inhibits viral DNA synthesis, preventing replication

183
Q

How does clindamycin interfere w/ protein translation?

A

By binding to ribosome

184
Q

What is the principle (or how is the principle done) in disc diffusion assay?

A

In this assay, filter paper discs are treated w/ a test antibacterial cmpnd and then placed onto a bacteria inoculated agar plate

185
Q

What are the discs needed in disc diffusion assay?

A

1) Discs treated w/ (+) control

2) Untreated disc [(-) control]

186
Q

What is the component of (+) control disc?

A

Usually a high effective disinfectant

187
Q

What is the principle of zone of inhibition?

A

It is the size of the area around the disc where bacteria can’t grow w/c gives an indication of the cmpnd’s antimicrobial efficacy

188
Q

What are the purposes of (+) controls?

A

1) Used to demonstrate that an exp is capable of working
2) These would let you know that the bacteria have grown on an agar plate and what inhibition growth on that plate looks like

189
Q

What should be done if the (+) control doesn’t turn out as expected?

A

Repeat exp

190
Q

What is the purpose of (-) controls?

A

To check those things that shouldn’t affect an exp don’t produce an effect

191
Q

Provide an ex of application where (-) controls are used

A

If you dilute a rgnt w/ a buffer, you might test that the buffer doesn’t have an effect on the exp

192
Q

What is a another form of a disc diffusion assay?

A

Uses a commercially available item an antibiotic multi-susceptibility test ring (AMT ring)

193
Q

What is the purpose of AMT ring?

A

To compare many antibiotics simultaneously

194
Q

What are the components of AMT ring?

A

Many discs, each of w/c is treated w/ a different test cmpnd

195
Q

What is the result if there are presence of zones of inhibition?

A

These gives an indication for an effective candidate antimicrobial

196
Q

What is epsilometer test?

A

It is related to disc diffusion assay and it is commercially available

197
Q

What is the principle of epsilometer test and what is its process?

A

Each strip of paper is impregnated w/ an increasing concentration of a candidate antimicrobial from the bottom to the top. The assay is processed by adding a test strip to a freshly bacteria-inoculated agar plate. After an incubation period, the MIC of a drug required to prevent microbial growth is determined by reading the concentration on the strip where antimicrobial growth is first inhibited

198
Q

How is the MIC of a drug read?

A

By reading the concentration on the strip where antimicrobial growth is first inhibited (the point of the tear-shaped zone of inhibition)

199
Q

What is the meaning of E-Test?

A

Epsilometer test

200
Q

What are zones of inhibition?

A

These are areas where no bacteria can grow around an antibiotic cmpnd

201
Q

What is a bacterial ‘lawn’?

A

It most often appears as a light-colored and opaque layer over a darker field of supportive agar jelly

202
Q

What is the interpretation for gaps in the bacterial lawn?

A

Gaps represent areas where growth has failed

203
Q

What are zones?

A

1) These are most commonly associated w/ antibiotic susceptibility tests such as diffusion disc assays
2) A zone can appear around diff test components depending on whether a component (like a doped filter disc) contains a cmpnd that can prevent bacteria from growing, replicating or simply being alive

204
Q

What is the interpretation for image A (for exs of zone of inhibition)?

A

No antimicrobial effect

205
Q

What is the interpretation for image B (for exs of zone of inhibition)?

A

Potential resistance or regrowth

206
Q

What is the interpretation for image C (for exs of zone of inhibition)?

A

Ambiguous outcome

207
Q

What is the interpretation for image D (for exs of zone of inhibition)?

A

True zone of inhibition

208
Q

What is the principle for image A (for exs of zone of inhibition)?

A

In this image, we see that although the bg lawn of bacteria is slightly lightened, there are many bacteria growing right up to the disc. There is no recordable antimicrobial effect

209
Q

What is the principle for image B (for exs of zone of inhibition)?

A

We can see a radius that appears to have been cleared, however, there are several colonies growing within this radius. This could represent colonies of resistant bacteria, or regrowth of bacteria following the decomposition of the antimicrobial agent. Either way, this test would normally be repeated in the lab, as there is no recordable clear zone of inhibition

210
Q

What is the principle for image C (for exs of zone of inhibition)?

A

There does appear to be a zone here, however, the zone is very small and there does appear to be a few colonies growing next to the plate. This ambiguity would lead to a repeat test if certainty was required. There is no clear zone here.

211
Q

What is the principle for image D (for exs of zone of inhibition)?

A

There is a very clear zone here w/ only a couple of small irregularities around the very edge of the zone. The bacteria-free area would be measured across its diameter and the distance recorded as the size of the zone

212
Q

Provide an ex of beta-lactam antibiotics

A

Penicillin

213
Q

What is the component of all beta-lactam antibiotics?

A

They carry a square-shaped beta-lactam ring at the core of their chemical structure

214
Q

What is the purpose of the square-shaped beta-lactam ring at the core of the chemical structure of all beta-lactam antibiotics?

A

This highly reactive feature is responsible for the antimicrobial effects

215
Q

What is the action of transpeptidase enzyme?

A

It is responsible for linking muramic acid side chains of peptidoglycan

216
Q

What is the result of the action by transpeptidase enzyme?

A

This mesh-linking activity creates a strong cell wall

217
Q

What are the action of penicillin?

A

It can mimic a component of the side chain and as such can irreversibly bind into the enzyme’s active site, preventing it from carrying out this crosslinking work

218
Q

What is the result of the action by penicillin?

A

Leads to degradation of the bacterial cell wall

219
Q

Provide an ex of the mode of function of all beta-lactam antibiotics

A

Penicillin binds to the transpeptidase enzyme

220
Q

What are the ways of how the bacteria can become resistant to beta-lactam antibiotics?

A

1) Mutation of the transpeptidase active site
2) Expression of a lactamase enzyme
3) Altered membrane permeability
4) Active efflux of the drug

221
Q

What is the principle of mutation of the transpeptidase active site (way of bacteria to become resistant to beta-lactam antibiotics)?

A

If the antibiotic can no longer bind into the target enzyme due to a conformational change, the drug can’t exert its effect anymore

222
Q

What is the principle of expression of a lactamase enzyme (way of bacteria to become resistant to beta-lactam antibiotics)?

A

Lactamase enzymes cleave the all-important square-shaped beta-lactam ring that is the source of this class of antibiotic’s effect. By cutting open the ring before the drug has had a chance to interact w/ its target, the enzyme can prevent any drug-target binding from taking place

223
Q

What is the principle of altered membrane permeability (way of bacteria to become resistant to beta-lactam antibiotics)?

A

Changes to the cell wall that prevent or slow down a drug’s entry to the cell can confer a degree of resistance. If the drug can’t reach the target, it can’t have an effect

224
Q

What is the principle of active efflux of the drug (way of bacteria to become resistant to beta-lactam antibiotics)?

A

Efflux pumps are transmembrane proteins that pump cmpnds out of the cell. If a bacteria begins to express a pump that can remove a drug quickly, the effect of that drug will be hugely reduced

225
Q

What are antimicrobial targets?

A

These are components of microbial cells that are either not present or are present in a very different from compared to host cells (like human or animal cells)

226
Q

What are the commonly targeted microbial components?

A

1) Bacterial transpeptidase
2) DNA gyrase
3) Bacterial ribosome
4) DNA
5) RNA polymerase

227
Q

Answer the ff questions:

Given target microbial component: Bacterial transpeptidase

a) What are the drugs present?
b) What are the actions of the drugs present to the target microbial component?
c) What are the outcomes of the action brought by drug present in response to target microbial component?

A

a) Beta-lactams (like penicillin)
b) Prevents the production of the cell wall by inhibiting cross linking enzyme
c) Cell wall breakdown and eventual lysis

228
Q

How is the production of cell wall prevented by beta-lactams to bacterial transpeptidase?

A

By inhibiting cross linking enzyme

229
Q

Answer the ff questions:

Given target microbial component: DNA gyrase

a) What are the drugs present?
b) What are the actions of the drugs present to the target microbial component?
c) What are the outcomes of the action brought by drug present in response to target microbial component?

A

a) Quinolone drugs (like ofloxacin)
b) Hijack enzyme to create breaks in the DNA
c) Prevents DNA replication and growth

230
Q

Answer the ff questions:

Given target microbial component: Bacterial ribosome

a) What are the drugs present?
b) What are the actions of the drugs present to the target microbial component?
c) What are the outcomes of the action brought by drug present in response to target microbial component?

A

a) Lincosamides (like clindamycin)
b) Prevents ribosomal translocation and protein production
c) Arrests cell growth

231
Q

Answer the ff questions:

Given target microbial component: DNA

a) What are the drugs present?
b) What are the actions of the drugs present to the target microbial component?
c) What are the outcomes of the action brought by drug present in response to target microbial component?

A

a) Nitroimidazoles (like metronidazole)
b) Converted to reactive form only inside microorganism cells and damages DNA
c) Prevents NA formation, preventing growth and replication

232
Q

What is the result of prevention of NA formation by nitroimidazoles to DNA?

A

Results to preventing growth and replication

233
Q

Answer the ff questions:

Given target microbial component: RNA polymerase

a) What are the drugs present?
b) What are the actions of the drugs present to the target microbial component?
c) What are the outcomes of the action brought by drug present in response to target microbial component?

A

a) Rifamycins (like rifampin)
b) Preventing the production of RNA by inactivating polymerase enzyme
c) Arrests cell growth and replication

Clinical Bacteriology (Laboratory) (24 decks)

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