sterilization, disinfection, and antisepsis- Exam IV Flashcards
(125 cards)
1
Q
transmission of infectious agents among patients and staff in a clinical environment:
A
cross-infection
2
Q
management strategies for risk control:
A
cross-infection control
3
Q
Possible sources of infection in the dental care setting includes:
A
- patients with infectious disease
- patients in the prodromal or convalescent stage of infection
- healthy (or asymptomatic) carriers of disease-causing organisms
- Environmental sources
4
Q
Environmental sources of infection in the dental care setting include:
A
airborne organisms or biofilms in waterlines or on equipment or instruments
5
Q
All patients are treated as though they are a potential source of infectious pathogens:
A
universal precautions
6
Q
Routes of spread of cross infection includes:
A
- airborne routes
- contact routes
- parental spread of cross-infection
7
Q
Airborne routes of spread of cross infection include:
A
dust-borne routes and aerosol routes
8
Q
Examples of dust-borne routes include:
____ from skin scales
___ from environmental dust
A
staph aureus; clostridium tetani
9
Q
sources of dust-borne routes include:
A
skin scales, wound dressings, & solid surfaces
10
Q
Examples of aerosol routes include:
A
large droplets and droplet nuclei
11
Q
large droplets are classified as:
A
contact
12
Q
Sources of aerosol routes include:
A
speaking, sneezing, and all intraoral procedures
13
Q
In what situations is there a massive increase of aerosol routes of cross-infection?
A
when using ultrasonic scaling, air-rotor, and air/water syringe
14
Q
aerosols can occur with or without:
A
aspiration
15
Q
Prevention of aerosol transmission includes:
A
- elimination or limitation of organisms at source
- interruption of transmission
16
Q
Contact routes of spread of cross-infection include:
A
- person-to-person
- equipment
- fluids
17
Q
Direct spread by hands and clothes or fomites; large droplets
A
person-to-person
18
Q
Person-to-person transmission is a ___ route of transmission
A
contact
19
Q
Person-to-person contact route of transmission is:
A
direct
20
Q
prevention of person to person contact spread =
A
hand washing, gloves, and protective clothing
21
Q
the contact route “equipment” route of spread of cross infection includes:
A
chairs, instruments, impression materials
22
Q
Prevention of equipment route of spread of cross infection includes:
A
- sterilization of instruments
- use of disposals
- disinfection of dental instruments
- environmental hygiene
- defining zones in the dental operatory
- disposal of infected waste
23
Q
the contact route “fluids” route of spread of cross infection includes:
A
dental water supplies
24
Q
Prevention of fluid route of spread of cross infection includes:
A
flushing water supply lines, using sterile water and using biocide in water
25
Sources of parenteral spread of cross-infection include:
blood, saliva, secretions
26
Inoculation of parenteral spread of cross infection is via:
eye, skin breach, mucous membrane, & sharps injury
27
A sharps injury would be what form of spread of cross infection?
parenteral
28
Prevention of parenteral spread of cross infection includes:
training in use and disposal of sharps, Hep B vaccine, wearing gloves, dressing wounds
29
The risk of infection following a needlestick from a seropositive HIV patient:
0.3%
30
The risk of infection following a needlestick from a seropositive HBV patient:
7-30%
31
Destruction of all microbial forms (including bacterial spores):
sterilization
32
Destruction of most microbial forms:
disinfection
33
What agents are typically used as disinfections:
usually chemical agents
34
Disinfectants are typically used on:
inanimate objects
35
List the categories of disinfectants:
1. high-level
2. intermediate level
3. low-level
36
Inhibition or elimination of microbes on living tissue:
antisepsis
37
Chemical agents that kill or inhibit growth of microorganisms when applied to tissue:
antiseptics
38
Reduction of microbial population to levels deemed safe (based on public health standards):
sanitization
39
Agents that kill microorganisms or inhibit their growth:
antimicrobial agents
40
"-cidal" refers to agents that:
kill
41
"-static" refers to agents that:
inhibit growth
42
Microorganisms are not killed:
instantly
43
The population of microbial death usually occurs:
exponentially
44
Microorganisms are considered to be dead when:
they are unable to reproduce in conditions that normally support their reproduction
45
When looking at an exponential plot of microbial survivors versus the minutes of exposure to heating t 121 degrees Celsius, once the population has been greatly reduced, the rate of killing may:
slow due to resistant individuals
46
Conditions influencing the effectiveness of antimicrobial agent activity include: (6)
1. population size
2. population composition
3. concentration or intensity of an antimicrobial agent
4. duration of exposure
5. temperature
6. local environment (pH, viscosity, etc.)
47
The use of physical methods in control of microbial agents include:
heat, low temps, filtration, and radiation
48
heat type that is effective against all types of microorganisms:
moist heat
49
Moist heat works by degrading ____, denaturing ____, and disrupting ___.
nucleic acids; proteins; membranes
50
an example of moist heat use in a dental practice:
autoclave
51
Heat type that is less effective, requiring higher temps and longer exposure times:
dry heat sterilization
52
How does dry heat sterilization work?
by oxidizing cell constituents and denaturing proteins
53
When measuring heat-killing efficiency what two values are we looking for?
1. Thermal death time (TDT)
2. Decimal reduction time (D or D-value)
54
TDT=
thermal death time
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D or D-value=
decimal reduction time
56
The shortest time needed to kill all microorganisms in suspension at a specific temp under defined conditions:
Thermal death time
57
The time required to kill 90% of microorganisms or spores in a sample at a specific temperature:
Decimal reduction time
58
Thermal death time is the shortest time needed to kill all microorganisms in a suspension at a ____ and under ____.
specific temperature; defined conditions
59
The decimal reduction time (D or D-value) is the time required to kill ____ or ___ in a sample at a specific temperature
90% of microorganisms or spores
60
The increase in temperature required to reduce D to 10% of original value:
Z value
61
Used to kill endospores efficiently:
autoclaves
62
Autoclaves use ____ to reach temps above boiling
saturated steam under pressure
63
A moist heat process that involves controlled heating at temperatures well below boiling:
pasteurization
64
What type of heat process is pasteurization?
moist heat
65
Reduces the total microbial population and thereby increases the shelf life of treated material:
pasteurization
66
Pasteurization of milk includes:
1. flash pasteurization (high temp short-term: HTST)
2. ultrahigh-temperature (UHT) sterilization
67
Describe flash pasteurization:
High temp short term (HTST)
72 degrees Celsius for 15 seconds and then rapid cooling
68
Describe ultra-high temperature (UHT) sterilization:
140-150 degrees Celsius for 1 to 3 seconds
69
Low temperature processes include:
freezing & refridgeration
70
stops microbial reproduction due to lack of liquid water:
freezing
71
In freezing, some microorganisms are killed by:
ice crystal disruption of cell membranes
72
How does freezing stop microbial reproduction?
due to lack of liquid water
73
A low temperature method that involves the slowing of microbial growth and reproduction:
refigeration
74
reduces microbial population or sterilizes solutions of heat-sensitive materials by removing microorganisms; also used to reduce microbial populations in air:
filtration
75
What types of filters are available for filtering liquids?
1. depth filters
2. membrane filters
76
thick fibrous or granular filters that remove microorganisms by physical screening, entrapment, and/or adsorption:
depth filters
77
pours membranes with defined pore size that remove microorganisms primary by physical screening:
membrane filters
78
What are two modes of filtering air?
1. surgical masks
2. high-efficiency particulate air (HEPA) filters
79
HEPA:
High-efficiency particulate air filters
80
What are two types of radiation?
1. ultraviolet (UV) radiation
2. ionizing radiation
81
UV radiation is limited to ____ because it does not penetrate ____.
surfaces; glass, dirt films, water, and other substances
82
Radiation that penetrates deep into objects:
ionizing radiation
83
Type of radiation that destroys bacterial endospores, but is not always effective against viruses
ionizing radiation
84
Used for sterilization and pasteurization of antibiotics, hormones, sutures, plastic disposable supplies, and food:
ionizing radiation
85
Phenolics include:
phenol & hexachlorophene
86
Commonly used as laboratory and hospital disinfectants:
phenolics
87
____ is a mixture of phenolics
lysol
88
How do phenolics work?
by disrupting cell membranes
89
Tuberculocidal, effective presence of organic material, and long lasting:
phenolics
90
What are the downfalls of phenolics?
disagreeable odor and can cause skin irritation
91
What are two examples of alcohols used as chemical for microbial control?
ethanol & isopropanol
92
Alcohols can be describe as ___ & ____ but not ___
bactericidal & fungicidal; sporicidal
93
Do alcohols work against viruses?
may inactivate SOME viruses
94
What is the mechanism of action for alcohols?
denature proteins and possible dissolve membrane lipids
95
alcohols are ___ % in water (cidal activity drops sharply when diluted below ___ concentration)
60-90%; 50%
96
Contain fluorine, chlorine, bromine, and iodine :
halogens
97
skin antiseptic
iodine
98
How does iodine work:
oxidizes cell constituents and iodinates proteins
99
Can iodine kill spores?
yes at high concentrations
100
What are the downfalls with iodine?
1. skin damage
2. staining
3. allergies
101
Iodine complexed with organic carrier:
iodophore
102
How does chlorine work?
oxidizes cell constituents
103
Important in disinfection of water supplies and swimming pools, used in dairy and food industries, effective household disinfectant:
chlorine
104
What is chlorine able to destroy? What can it not destroy?
vegetative bacteria and fungi but NOT spores
105
What can form when chlorine reacts with organic matter?
carcinogenic compounds
106
Ions of mercury, silver, arsenic, zinc and copper are all examples of:
heavy metals
107
Heavy metals can be described as ___ but ___
effective but usually toxic
108
Heavy metals combine with and inactivate ___ but also may precipitate ___.
proteins; proteins
109
Cetylpyridinium chloride and benzalkonium chloride are examples of:
quaternary ammonium compounds
110
organic molecules with hydrophilic and hydrophobic ends:
quaternary ammonium detergents
111
Quaternary ammonium compound detergents can act as ___ & ___.
wetting agents & emulsifiers
112
What type of detergents are effective disinfectants?
cationic detergents
113
Cationic detergents kill most ____ but not ___ or ___
bacteria; mycobacterium tuberculosis or endospores
114
What is the advantage of cationic detergents? what is the disadvantage of cationic detergents?
advantage: safe & easy to use
disadvantage: inactivated by hard water & soap
115
- highly reactive molecules
- sporicidal and can be used as chemical sterilants
- combine with and inactivate nucleic acids and proteins
aldehydes
116
Ethylene oxide and betapropriolactone are both examples of:
sterilizing gases
117
Sterilizing gases are used to sterilize:
heat-sensitive materials
118
Sterilizing gases can be described as ___ & ___
microbicidal and sporicidal
119
How doe sterilizing gases work?
combine with and inactivate proteins
120
Spaulding inanimate objects classification is used for:
instruments or objects used in dentistry
121
Classify the following objects: category, level and risk:
-touch bone or penetrate tissue
-blood present (scalpels, forceps, scalers, probes, and implants)
category: critical
level: heat sterilization
risk: very high
122
Classify the following objects: category, level and risk:
-touch mucous membrane but not penetrate
-no blood (mirrors, burnishers, amalgam carriers, etc.)
category: semi-critical
level: sterilization, high-level disinfection
risk: moderate
123
Classify the following objects: category, level and risk:
- unbroken skin contact
-no blood (masks, clothing, BP cuffs)
category: non-critical
level: intermediate level
risk: low
124
Classify the following objects: category, level and risk:
-no direct patient contact
-no blood (door knobs, floors, walls, counters, mops, and other housekeeping equipment)
category: environmental surfaces
level: low level disinfection; sanitation
risk: minimal
125
