Chapter 11 Flashcards
(119 cards)
0
Q
Sterilization
A
The destruction of all microbial life
1
Q
What are the four methods of microbial control outside of the body?
A
Sterilization
Disinfection
Antisepsis
Decontamination
2
Q
Disinfection
A
Destroys most microbial life, reducing contamination on inanimate surfaces
Does not destroy becterial endospores
3
Q
Antisepsis
A
Aka degermation
Same as disinfection except a living surface is involved
4
Q
Decontamination
A
Aka sanitization
The mechanical removal of most microbes from an animate or inanimate surface
5
Q
What are the primary targets of microbial control?
A
Microorganisms that are capable of causing infection or spoilage
6
Q
Are the microbial populations simple or mixture?
A
Mixture due the extreme differences in resistance and harmfulness
7
Q
What type of harmful microbes are primary targets that are hard to control?
A
Bacterial vegetative cells andendospores, fungal hyphae and spores, yeasts, protozoans trophozoites and cysts, worms, viruses, and prions.
8
Q
Which microbe is considered the most resistant?
A
Bacterial endospores
Goal is to sterilize bc any process that kills endospores will also kill all less resistant microbial forms
Disinfection and antisepsis is used upon microbes that are less hardy than endospores
9
Q
Sterile
A
When all microbial life has been destroyed
10
Q
What objects can be sterilized
A
Inanimate bc this damages living tissue
11
Q
Type of sterilizing agents are….
A
Heat and chemicals that destroy endospores
12
Q
Sepsis
A
The growth of microorganisms in the blood and other tissues
13
Q
Asepsis
A
Any practice that prevents the entry of infectious agents into sterile tissues and thus prevents infection
14
Q
Antiseptics
A
Chemical agents in antisepsis
Can be applied directly to exposed body surfaces
15
Q
-cide
A
To kill
16
Q
Bactericide
A
Chemical that destroys bacteria except for those in endospore stage
17
Q
Fungicide
A
Chemical that kill fungal spores, hyphae and yeasts
18
Q
Virucide
A
Chemical known to inactivate viruses, especially on living tissue
19
Q
Sporicide
A
Agent capable of destroying bacterial endospores
Sporocidal agent can also be a sterilant bc it can destroy the most resistant of all microbes
20
Q
Other names for chemical agents that kill microorganisms
A
Germicide and microbicide
21
Q
-stasis -static
A
To stand still
22
Q
Bacteristatic
A
Prevent the growth of bacteria on tissues or on objects in the environment
23
Q
Fungistatic
A
Chemicals that inhibit fungal growth
24
Microbistatic
Chemicals used to control microorganisms in the body
| Microbicidal is too toxic for human tissues
25
Sanitization
Any cleansing technique that mechanically removes microorganisms as well as other debris to reduce contamination to safe levels
Ex: soap or detergent
26
What is used for air sanitization to reduce airborne microbes
Uv lamps
27
What method is used to reduce the number of microbes on the skin by scrubbing or immersing in chemicals?
Antisepsis
28
Critical medical devices?
Those that are expected to come into contact with sterile tissues
Must be sterilized before use
29
Semicritical devices?
Those that come into contact with mucosal membranes
| Must receive high level disinfection and should be sterilized
30
Noncritical items
Those that dont touch the patient or are only expected touch intact skin
Ex: blood pressure cuffs, crutches
Require low level disinfection unless contaminated with body fluids
31
Death
The permanent termination of an organisms vital processes
32
Determining microorganisms death?
They show no vital signs
| Must see if the microbial cell can still reproduce when exposed to a suitable environment (ideal conditions)
33
Graphing of microorganism death?
Shown in logarithmic manner as time or concentration of the agent is increased
34
Are old or young microbial cells targeted by an agent?
Young active cells are targeted due to the high metabolic activity rate
35
Factors that influence the action of antimicrobial agents
Number if microorganisms
Number if species in a population
The environment in which the population is cultured in
Temp and ph
Concentration of agent
Mode of action of agent
Prescence of solvents, interfering organic matter, and inhibitors
36
Mode of action
An antimicrobial agent's adverse effect on cells
37
How do antimicrobial agents work?
They have more than one cellular target , inflicting damage progressively until the cell is no longer able to survive
Agents that are least selective in their targeting are more effective against a wide range of microbes
38
Four categories of cellular targets of physical and chemical agents
Cell wall
Cell membrane
Cellular synthetic process (dna, rna)
Proteins
39
Cell wall maintains....
Structural integrity of bacterial and fungal cells
40
How do chemical agents damage a cell wall?
Blocking its synthesis, digesting it, or breaking down its surface
This allows for the cell to lyse
41
In gram negative bacteria, what can disurpt cell walls?
Alcohol and detergent
42
If a cells membrane becomes disrupted by a chemical agent, what happens?
Cells loses its selective permeability and cant prevent the loss of vital molecules or keep damaging chemicals from entering
43
Sufactants
Detergents that work as microbial agents
Polar molecules with hydrophobic and hydrophillic regions that can bind with lipid layer and penetrate the internal hydrophobic region of membrane
This creates leaky spots
44
What antibiotic binds to ribosomes of bacteria in a way that stops peptide bonds from forming?
Chloramphenicol
45
If an agent can disturb the process of dna replication and transcription or changes the genetic code is known as a
Antimicrobial
| Some bind irreversibly to dna and some are mutagenic antimicrobial
46
Native state
Proteins in a three deminsional state
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Denature
Disrupt proteins through bonds breaking the secondary and tertiary structure of proteins
Causes protein to unfold or create irregular loops
Caused by coagulation by moist heat
Strong organic solvents can also denature proteins
48
What attaches to the active site of the protein and prevent it from interacting with its correct substrate?
Metallic ions
| Nonselective to microbes
49
Most prominent physical antimicrobial agent is
Heat
50
Which one is microbicidal and which is microbistatic, high temp and low temp
```
High= cidal
Low= static
```
51
Moist heat
Occurs in the form of hot water, boiling water or steam
60 celsius to 135 celsius
Steam regulated by adjusting pressure
Coagulates and denatures proteins
52
Dry heat
Air with low moisture content that has been heated by flame or electric heating coil
160 celsius to a couple thousand celsius
Dehydrates the cell and denatures proteins
53
Which heat is at lower temps and shorter exposure times?
Moist heat
| Same effects as dry heat
54
At high temps, dry heat does what to cells?
Oxidizes cells which burns them to ashes
55
What microbes has the greatest resistance and the least resistance to moist and dry heat?
Greatest is bacterial endospores, requires temps above boiling for destruction
Least is vegetative states of bacteria and fungi
56
For bacteria, what are the death times with moist heat?
50 celsius for 3 minutes to 60 celsius for 60 min
57
For viruses, what is the death times for moist heat?
55 celsius 2 to 5 min to 60 celsius for 600 min
58
For all non heat resistant forms of bacteria, yeasts, molds, protozoa, worms and viruses are destroyed by exposure of
80 celsius for 20 min
59
High temperatures require
| Lower temperatures require
High requirs shorter exposure time
| Low requires longer exposure time
60
Thermal death time
Combination of temperature an exposure time
| The shortest length of time required to kill all test microbes at a specified temp
61
Thermal death point
The lowest temp required to kill all microbes in a sample in 10 min
62
Four methods moist heat is employed to control microbes is
Boiling water
Pasteurization
Nonpressurized steam
Steam under pressure
63
What is the benefit of cold treatment?
Slow growth of cultures and microbes in food during processing and storage.
Retards activities of microbes
64
Desiccated
Vegetative cells directly exposed to normal room air gradually become dehydrated
Reduces water that is needed for microbial growth
65
What microbes can withstand long periods of desiccation?
Viruses and fungal spores
66
Lyophilization
Combo of drying and freezing
| Method used to preserve microorganisms and other cells in a viable state for many years
67
Radiation
Energy emitted from atomic activities and dispersed at high velocity through matter or space
Gamma rays, x rays, uv radiation
68
Irradiation
Bombardment with radiation
Cell bombarded by waves or particles, molecules absorb some of the energy leading to ionizing radiation or nonionizing radiation
69
Ionizing radiation
Radiation ejects orbital electrons from an atom, it causes ions to form
Damages proteins which in turns damages dna
Chemical changes in organelles and production of toxic substances
Ex:gamma rays, x rays, high speed electrons
70
Nonionizing radiation
Uv excites atoms by raising them to a higher energy state but does not ionize them
Creates abnormal bonds in dna
71
Cold sterilization is also known as
Irradiation
Sterilizes without heating
Other source for sterilizing without using heat
72
Which rays are the most penetrating, intermediate and least?
Most is gamma rays
Intemediate is x rays
Least is cathode rays
73
Uv radiation ranges from....
100 nm to 400 nm
| Most lethal at 240 nm to 280 nm
74
What is the source of uv radiation?
Germicidal lamp
| 254 nm
75
Why does an object have to be directly exposed to UV for the full effect?
Uv radiation passes readily through air, slightly through liquids, and poorly through solids
76
How does uv radiation damage dna?
Damages the pyrimidine bases which form abnormal bonds called pyrimidine dimers. Bond with adjacent bases on same dna strand
Creates free radicals which bind to dna, rna and proteins
77
Uv radiation destroys....
Fungal cells and spores, bacterial vegetative cells, protozoa, and viruses
78
Filtration
Effective method to remove microbes from air and liquids
Filter has openings that allow fluid to pass through but too small for microorganisms
Filters are usually thin membranes of cellulose acetate, polycarbonate, and variety of plastic materials
79
Filtration is used for?
Liquids that cannot withstand heat such as blood and serum, vaccines, drugs, iv fluids, enzymes and media
Air filters also remove airborne microorganisms
80
What can be added in large amounts to foods to create a hypertonic environment for bacteria in foods?
Salt or sugar
81
Aqueous
Solutions containing pure water as the solvent
82
Tinctures
Those dissolved in oure alcoholor water alcohol mixtures
83
Qualities wanted in a germicide
Rapid action in low concentrations
Solubility in water or alcohol and long term stability
Broad spectrum microbicidal action without toxicit to human tissue
Penetration of inanimate surfaces to sustain a cumulative or persistant action
Resistance to becoming inactivated by organic matter
Noncorrosive or nonstaining properties
Sanitizing and deoderizing properties
Affordability and availability
84
High level germicides
Kill endospores and are sterilants
85
Intermediate level germicides
Kill fungal spores, reistant pathogens, and viruses
86
Low level germicides
Eliminate vegetative bacteria, vegetative fungal cells, some viruses
87
Factors that control the effects of a germicide
```
Nature of microorganisms being treated
Nature of material being treated
Degree of contamination
Time of exposure
Strength and chemical action of germicide
```
88
What is the action of most germicides?
Attack cellular targets
89
Solutions of low dilution or high percentage contains?
More of the active chemical and are more germicidal
90
What can hinder the penetration of disinfectant and possible form bonds that reduce its activity?
Large amounts of organic material
91
Halogens are
Flourine, bromine, chlorine, iodine and a group of non metallic elements
Group VII
These elements or microbicidal and are sporicidal when they are exposed for longer periods of time
92
Chlorine
Used as liquid or gas
Combine with water and releases hypochlorus acid which oxidizes the sulfhydryl group on amino acid cysteine and interferes with disulfide bridges on numerous enzymes
Kills bacteria and endospores, fungi, viruses
Less effective when exposed to light, alkaline ph, excess organic matter
93
Hypochlorites
Most used of chlorine
| Sanitization and disinfection of swimming pools, water, fresh foods
94
Iodine
Penetrates cells of microorganisms, interferes with hydrigen and disulfide bonding of proteins
All microorganisms are killed
95
Iodophors
Complexies of iodine and alcohol
Allows slow release of free iodine and increase its degree of penetration
Less prone ro staining or irrittating tissues
96
Phenol
Derived from distillation of coal tar
| First used as major antimicrobial chemical
97
Phenol coefficient
Copmares a chemicals antimicrobial properties to those of phenol
98
Phenolics
Consist of one or more aromatic carbon rings with added functional groups
Destroy vegetative bacteria, fungi, and most viruses
Toxicity makes them too dangerous to use as antiseptics
99
High concentrations of phenolics
Disurpt cell walls and membranes and precipitating proteins
100
Low concentrations of phenolics
Inactivate certain critical enzyme systems
101
Chlorhexidine
Complex organic base containing chlorine and two phenolic rings
Targets cell membranes and protein structure
High conentrations: bactericidal for both gram positive and gram negative bacteria
102
Alcohols
Hydrocarbons with one or more OH functional groups
Concentration of 50% or more disolve membrane lipids, disrupt cell surface tension, compromise membrane integrity
In alcohol water solutions of 50 to 95%, the alcohol enters cytoplasm denatures proteins through coagulation
Destroy fungal spores, vegetative forms, deactivates enveloped viruses
103
What does high concentrations of alcohol do to the cell?
Dehydrates cell and inhibits growth but does not denature proteins
104
Hydrogen peroxide
Liquid that decomposes in the presence of light, metals, or catalase into water and oxygen gas
Oxygen forms hydroxyl free radicals which are toxic and reactive to cells
Bactericidal, virucidal,fungicidal, and high concentrations sporicidal
105
What are the most effective detergents?
Positively charged (cationic), particularly the quaternary ammonium compounds (quats)
106
Cationic detergents
Amphipathic (two headed), positively charged end binds well with the negatively charged end of bacterial surface proteins, while the long uncharged hydrocarbon chain allows detergent to disrupt cell membrane
Low level detergents and work best in alkaline solutions
107
Effects of detergents at high and low concentrations
```
High= quaternary ammonium compounds are effective against some gram positive bacteria, viruses, fungi, and algae
Low= microbistatic effects
```
108
What heavy metals have significance as germicides?
Mercury and silver
109
Oligodynamic action
Having antimicrobial effects in exceedingly small amounts
| Zinc and iron needed as cofactors on enzymes in small quantities
110
Heavy metal germicides contain either....
Inorganic or organic metallic salt, and they come in the form of aqueous solutions, tinctures, ointments or soaps
111
Most metals exert microbicidal effects by bonding to....
Functional groups of proteins and inactivating them.
| Destroy microbes, vegetative bacteria, fungal cells and spores, algae, protozoa, and viruses
112
Drawbacks to using heavy metals as microbial control
Metals are toxic to humans
Cause allergic reactions
Large quantities of biological fluids ans wastes neutralize their actions
Microbes can develop resistance to metals
113
Aldehydes
Have CHO functional group on the terminal carbon
114
Glutaraldehyde
Cross links protein molecules on the cell surface causing amino acids to become alkylated, hydrogent atom on amino acid gets replaced by glutaraldehyde molecule
115
Glutaraldehyde destroys...
Endospores in 3 hours and fungi and vegetative bacteria in a few minutes
Used as sterilant and high level disinfectant
Unstable in high temp and ph
116
Formalin
Aqueous solution that formaldehyde disolves in water
Microbicidal through its attachment to nucelic acids and functional groups of amino acids
Intermediate to high level disinfectant
117
Ethylene oxide
Exists as a gas in room temp
Stong alkylating agent and reacts with functional groups of dna and proteins
Block dna replication and enzymatic actions
118
Chlorine dioxide
Gas used as sterilant
| Alkylating agent which disrupts proteins and is effective against vegetative bacteria, fungi, viruses, and endospores
