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Microbiology Exam 2 (Modules 3-5) > Chapter 9 > Flashcards

Chapter 9 Flashcards

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1
Q

Process that destroys or removes all viable microorganisms (including viruses)

A

Sterilization

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2
Q

Examples of sterilizing agents

A

Heat (autoclave)

Sterilants (chemical agents capable of destroying endospores)

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3
Q

Physical process or a chemical agent that destroys vegetative pathogens but not bacterial endospores; removes harmful products of microorganisms (toxins) from material

A

Disinfection

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4
Q

Examples of disinfection agents

A

Bleach
Iodine
Heat (boiling)

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5
Q

Cleansing technique that mechanically removes microorganisms as well as other debris to reduce contamination to safe levels

*important to restaurants, dairies, breweries, and other commercial entities

A

Contamination/Sanitization

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6
Q

Examples of contamination/sanitization agents

A

soaps
detergents
commercial dishwashers

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7
Q

Reduces the number of microbes on the human skin; a form of decontamination but on LIVING tissues

A

Antisepsis/Degermation

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8
Q

Examples of antisepsis/degermation agents

A

alcohol

surgical hand scrub

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9
Q

Microbe that is extraordinarily resistant to heat and chemicals

A

prions

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10
Q

toughest form of microbial life

A

bacterial endospores

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11
Q

chemical that destroys bacteria except those in the endospore stag

A

Bactericide

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12
Q

having the capacity to kill bacteria is __________

having the capacity to interfere with bacteria reproduction is _______

A
  1. bactericidal

2. bacteristatic

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13
Q

a chemical that can kill fungal spores, hyphae, and yeasts

A

fungicide

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14
Q

any chemical known to inactivate viruses, especially on living tissue

A

virucide

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15
Q

an agent capable of destroying bacterial endospores

A

sporicide

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16
Q

an agent lethal to non-endospore-forming pathogens

A

germicide

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17
Q

chemicals that kill microorganisms

A

microbicides

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18
Q

defined as the growth of microorganisms in the blood and other tissues

A

sepsis

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19
Q

refers to any practice that prevents the entry of infectious agents into sterile tissues and therefore prevents infection

A

asepsis

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20
Q

a growth-inhibiting agent used on tissues to prevent infection

A

antiseptic

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21
Q

agents that prevent the growth of bacteria on tissues or on objects in the environment.

A

bacterisatic

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22
Q

medical devices that are expected to come into contact with sterile tissue, ie. syringe needle or artificial hip

; must be sterilized

A

Critical medical devices

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23
Q

medical devices that come into contact with mucosal membranes, ie. endoscopy tube

; must receive high-level disinfection and preferably sterilization

A

semicritical medical devices

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24
Q

medical devices that do not touch the patient or are only expected to touch intact skin, ie. blood pressure cuffs or crutches

; require low level disinfection (unless they become contaminated with blood or body fluids)

A

noncritical medical devices

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25
Q

autoclaving

A

steam sterilization

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26
Q

phenomenon that involves the permanent termination of an organism’s vital processes

A

death

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27
Q

Why is microbial death of an organism composed of just one or a few cells hard to detect?

A

b/c they reveal no conspicuous vital signs to begin with

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28
Q

Why is microbial death of an organism composed of just one or a few cells hard to detect?

A

b/c they reveal no conspicuous vital signs to begin with

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29
Q

What is the accepted microbiological definition of death?

A

permanent loss of reproductive capability even under optimum conditions

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30
Q

What factors influence the effectiveness of antimicrobial agents?

A

of micros
nature of micros (all different kinds?)
temperature/pH of environment
concentration (dosage/density) of the agent
mode of action of the agent (how does it kill or inhibit?)
presence of solvents, interfering organic matter, and inhibitors

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31
Q

an antimicrobial agent’s adverse effect on cells is called its

A

mode or mechanism of action

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32
Q

what are the four general categories of cellular targets of physical and chemical agents

A
  1. cell wall
  2. cytoplasmic membrane
  3. cellular synthetic processes (DNA, RNA)
  4. proteins
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33
Q

effects of agents on CELL WALL

A

blocking its synthesis or digesting it

ie. alcohol, detergents, chemicals

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34
Q

effects of agents on CYTOPLASMIC MEMBRANE

A

agents disrupt the lipid layer which opens up the membrane and allows damaging chemicals to enter the cell and important ions to exit the cell

ie. alcohol and detergents

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35
Q

effects of agents on CELLULAR SYNTHESIS

A

disrupt synthesis via the ribosomes which inhibits proteins needed for growth and metabolism and prevents multiplication

agents can also change genetic codes (mutation)

ie. formaldehyde, radiation, ethylene oxide

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36
Q

effects of agents on PROTEINS

A

denaturing of proteins

prevents some proteins from interacting with their chemical substrates

ie. moist heat, alcohol, phenolics

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37
Q

SARS-CoV-2 is an _________ virus, and its ______ is susceptible to both detergents and alcohol.

A
  1. enveloped

2. envelope

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38
Q

least resistant microbial entities

A

vegetative forms of cells

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39
Q

The vast majority of microbes in the same environment that humans live in can be controlled by

A

abrupt changes in their environment, such as heat

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40
Q

elevated temperatures that exceed the maximum growth temp are

A

microbicidial

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41
Q

lower temperatures below the minimum growth temp are

A

microbistatic

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42
Q

what is the temp range for moist heat?

A

60-135 dgerees Celsius

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43
Q

dry heat refers to hot air such as in an oven, and its temp range is

A

160 degrees to several thousand degrees Celsius

44
Q

_____ heat can achieve the same effectiveness as ___ heat but with lower temperatures and and SHORTER exposure time

A
  1. Moist

2. Dry

45
Q

Effect of moist heat

A

damages many cellular structures
but its most lethal effect is the denaturation and coagulation of proteins which QUICKLY/PERMANENTLY halts cellular metabolism

46
Q

with MOIST heat, how long does it take to sterilize at 134 degrees C?

A

3 minutes

47
Q

With DRY heat, how long does it take to sterilize at 140 degrees C?

A

180 minutes

48
Q

How does dry heat effect cells?

A

dehydrates the cell, removing necessary water for metabolic reactions
also denatures proteins

*However, lack of water can actually increase the stability of some protein conformations

49
Q

At very high heat what does DRY heat do to cells?

A

It oxidizes them and burns them to ashes, which is used in incineration in the medical industry or when a loop is flamed

50
Q

which two microbes in their vegetative form are the least resistant to most and dry heat?
Which microbe exhibits the greatest resistance to moist and dry heat?

A

bacteria and fungi

bacterial endospores

51
Q

destruction of endospores requires temps above ________

A

boiling

52
Q

viruses are surprisingly resistant to ______.

Hepatitis A virus can tolerate _____ at 60 degrees C for 600 minutes.

A

heat

53
Q

defined as the shortest length of time required to kill all test microbes at a specified temperature; is a combination of two variables- heat and time.

A

Thermal death time (TDT)

54
Q

defined as the lowest temperature required to kill all microbes in a sample in 10 minutes

A

Thermal death point (TDP)

55
Q

commercial canneries heat low-acid foods at 121 degrees C for 30 minutes, because this _______ food

A

sterilizes

56
Q

boiling water is a mode of _________

A

disinfection

57
Q

Pasteurization is a mode that ________

A

disinfects

58
Q

steam under pressure (autoclaving) is a form of _______

A

sterilization

59
Q

Incineration and hot air oven heat are forms of

A

sterilization

60
Q

principal benefit of cold treatment

A

slow down the growth of cultures and microbes during food processing and storage

*is microbistatic

61
Q

to dry thoroughly; to preserve by drying

A

desiccation

62
Q

some pathogens die after hours of air drying such as streptococcus pneumoniae, but many are not killed and some are ________

A

preserved

63
Q

_______ can be a valuable way to preserve foods because it greatly reduces the amount of water available for microbial growth

A

Desiccation

64
Q

combination of freezing and drying that is a common method of preserving microorganisms and other cells in a viable state for many years

A

lyophilization

65
Q

As a general rule _________, ____________, and ______________ should not be construed methods of disinfection and sterilization because there antimicrobial effects are erratic and uncertain.

A

freezing, chilling, and desiccation

66
Q

defined as energy emitted from atomic activities and dispersed at high velocity through matter or space

A

radiation

67
Q

order the different types of radiation from smallest energy to increasing energy

A

UV -> X rays -> Gamma rays

68
Q

list two types of ionizing radiation and what they do

A

gamma and x rays

->highly effective in sterilizing

69
Q

the application of radiant energy for diagnosis, therapy, disinfection, or sterilization

A

irradiation

70
Q

_____ radiation ranges in wavelength from approximately 100-400nm (most lethal from 240-280nm); works to disinfect and can cutdown airborne microbes as much as 99%

A

ultraviolet

71
Q

how does UV radiation damage cells?

A

causes inappropriate formation of bonds between two adjacent bases on a DNA strand

72
Q

______ in an effective physical method to remove microbes from the air and liquids; fluid or air is trained through a filter with openings large enough for fluid to pass through but too small for microorganisms to pass through

A

filtration

73
Q

most modern microbiological ________ are thin membranes of cellulose acetate, polycarbonate, and a variety of plastic material (Teflon, nylon) whose pore size can be carefully controlled and standardized.

A

filters

74
Q

filtration is used to prepare liquids that cannot withstand _______, including serum and other blood products, vaccines, drugs, IV fluids, enzymes, and media.

A

heat

75
Q

adding large amounts salt or sugar to foods creates a __________ environment for bacteria in the foods, causing plasmolysis and making it impossible for the bacteria to multiply

A

hypertonic

76
Q

solutions containing pure water as a solvent are termed

A

aqueous

77
Q

solutions containing pure alcohol or alcohol-water mixtures are termed

A

tinctures

78
Q

list desirable qualities in a germicide

A

rapid action in low concentrations
solubility in water or alcohol and long term stability
broad-spectrum microbicidal action without being toxic to human and animal tissues
penetration of inanimate surfaces without being toxic to human and animal tissues
resistance to becoming inactivated by organic matter
not corrosive and non-staining
sanitizing and deodorizing properties
affordable and available

79
Q

High-level germicides

A

kill endospores and are sterilants

80
Q

intermediate-level germicides

A

kill fungal spores and resistant pathogens such as the bacterium that causes tuberculosis, and viruses

81
Q

low level germicides

A

eliminate vegetative bacteria, vegetative fungal cells, and some viruses

-clean straps, electrodes, furniture that touches skin

82
Q

what are some organisms that CHLORINE destructs

A

mycobacterium tuberculosis
entamoeba cysts (protozoa)
Hep A virus

83
Q

what are some organisms that ETHYL ALCOHOL destructs

A

Staphylococcus aureus
Escherichia coli
Poliovirus

84
Q

what are some organisms that HYDROGEN PEROXIDE destructs

A

Staphylococcus aureus
Neisseria gonorrhoeae
Herpes simplex virus

85
Q

what are some organisms that QUATERNARY AMMONIUM COMPOUND destructs

A

Staphylococcus aureus

Salmonella typhi

86
Q

what are some organisms that ETHYLENE OXIDE GAS destructs

A 
Streptococcus faecalis
Influenza virus (10,000 mg/L concentration kills virus in 25 hours)
87
Q

Would an enveloped or non-enveloped virus be inactivated by a alcohol based hand wash?

A

Enveloped because it is a membrane, and alcohol’s major action is to dissolve membrane lipids

88
Q

Germicidal Categories According to Chemical Group

Chlorine

A

Halogen

  • can slowly kill endospores; kills all other microbes
  • suspends metabolic reactions
  • less effective if exposed to light, excessive organic matter, and alkaline pH
  • capable of sterilization
89
Q

Germicidal Categories According to Chemical Group

Iodine

A

Halogen
-can kill endospores and all other microbes
-interferes with hydrogen and disulfide bonding of proteins
-can be extremely irritating to the skin
(many iodophors banned in 2017)
-sterilization

90
Q

Germicidal Categories According to Chemical Group

Oxidizing agents
HYDROGEN PEROXIDE

A
  • kill endospores and all other microbes
  • oxygen forms free radicals which are highly toxic/reactive to cells
  • sporicidal only in high concentrations
  • sterilization
91
Q

Germicidal Categories According to Chemical Group

Aldehydes

A
  • kill endospores and all other microbes
  • disrupts the activity of enzymes and other proteins within the cell
  • Glutaraldehyde is broad spectrum and kills rapidly
  • sterilization
92
Q

Germicidal Categories According to Chemical Group

Gaseous sterilant/disinfectants

A
  • ethylene oxide kills endospores; other gases are less effective
  • reacts with functional groups of DNA and proteins and blocks both DNA replication and enzymatic action
  • ethylene oxide is explosive
  • used on syringes, surgical supplies, etc.
  • sterilization
  • can damage lungs, eyes, mucous membrane if direct contact

*Ethylene oxide is rated as a carcinogen by the gov

93
Q

Germicidal Categories According to Chemical Group

Phenol (carbolic acid)

A
  • kills some bacteria, fungi, viruses
  • in high concentrations they are cellular poisons disrupting cell walls and membrane proteins
  • in low concentrations they inactivate certain critical enzyme systems
  • many phenols banned in consumer products in 2017
94
Q

Germicidal Categories According to Chemical Group

Chlorhexidine

A
  • kills most bacteria, viruses, fungi
  • targets bacterial membranes, where selective permeability is lost, bacterial cells walls, and proteins, resulting in denaturation
95
Q

Germicidal Categories According to Chemical Group

Alcohol

A
  • kills most bacteria, viruses, fungi

- dissolves membrane lipids/compromises membrane integrity

96
Q

Germicidal Categories According to Chemical Group

Detergents

A
  • kills some bacteria viruses and fungi

- disrupts cytoplasmic membrane through proteins

97
Q

Germicidal Categories According to Chemical Group

Heavy Metal Compounds

A
  • kills some bacteria, viruses, fungi
  • bind to functional groups of proteins and inactivate them
  • not effective against endospores
  • can be toxic to inhale, ingest, and absorb
98
Q

Germicidal Categories According to Chemical Group

Acids and Alkalis

A
  • kills some bacteria, fungi, and viruses
  • alters pH
  • large pH changes can be corrosive
99
Q

What method would you use following a surgical procedure to sterilize medical equipment?

a. Filtration
b. Autoclaving
c. Incineration
d. Radiation

A

b. Autoclaving

100
Q

give an example of when Chlorhexidine is used

A

to rinse the mouth during times when a tube is inserted into the mouth or nose for a ventilator, this way it can kill microbes and prevent them from migrating to the lungs

-chlorhexidine targets bacterial cell walls and membranes, as well as proteins

101
Q

DNA repair mechanisms can help alleviate the effects of

a. UV radiation
b. Alcohol disinfection
c. Autoclaving
d. Dry heat

A

a. UV radiation

102
Q

Cytoplasmic enzymes are most likely to be disrupted by

a. UV light
b. Low temps
c. High temps
d. Detergents

A

c. High temps

103
Q

Transcription is targeted most directly by

a. Quats
b. Detergents
c. UV radiation
d. Alcohol

A

c. UV radiation

104
Q

peracetic acid

A

hydrogen peroxide

105
Q

The most versatile method for sterilizing heat-sensitive liquids is

a. UV radiation
b. exposure to ozone
c. peracetic acid
d. filtration

A

d. filtration

Microbiology Exam 2 (Modules 3-5) (13 decks)

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