Physical and Chemical Methods of Microbial Growth Control (Chapter 9)

Question 1

Sterilization is… ;

used on inanimate objects or live tissues?

Answer 1

The process that destroys or removes all viable microbes including endoscopes and viruses ;

inanimate objects

Question 2

What does disinfection mean?; used on inanimate objects or live tissues?

Answer 2

Physical process or chemical agent to destroy vegetative pathogens ;

inanimate

Question 3

Decontamination/ Sanitization is… ; used on inanimate objects or live tissues?

Answer 3

Cleansing technique that mechanically removes microbes and debris ;

inanimate

Question 4

Antisepsis/Degermation does what? ; used on inanimate objects or live tissues?

Answer 4

Reduces the number of microbes on the human skin ;

living tissue

Question 5

What is the most resistant type of microbe?

Answer 5

Cysts, theyre like the eukaryotic version of endospores

Question 6

Whats the standard in terms of cleansing?

Answer 6

If you take out bacterial endospores, you can pretty much take out anything else

Question 7

Whats the least resistant microbes?

Answer 7

enveloped viruses

Question 8

Sterilization and disinfection are _______

Answer 8

processes

Question 9

What are the 5 agents used in process?

Answer 9

1. Bactericide
2. Fungicide
3. Virucide
4. Sporicide, 5.Germicide/microbiocide

-ide (killing)

Question 10

What is sepsis? asepsis?

Answer 10

the growth of microorganisms in the blood and other tissues (infection)

Asepsis- (without infection)
any practice that prevents the entry of infectious agents into sterile tissues

Question 11

What is an antiseptic?

Answer 11

antiseptics are applied to wounds to destroy or inhibit the growth of pathogens in wounds

Question 12

What does stasis and static mean?

Answer 12

“to stand still” prevent the growth of

Question 13

What are the 3 “-statics?”

Answer 13

1. Bacteristatic
2. Fungistatic
3. Microbistatic

Question 14

What are the 3 devices that need to be cleaned? describe them and give an example

Answer 14

Critical medical devices - expected to come in contact with sterile tissues

• Must be sterilized
  ex: syringe needle or artificial hip.

Semicritical devices - come into contact with mucosal membranes (open mouth, eyes)

• high level disinfection/ preferably sterilized
  ex: endoscope

Noncritical devices - do not touch the patient or only touch intact skin

• low level disinfection unless contaminated
  ex: blood pressure cuffs or crutches

Question 15

What are the 4 methods of microbial control?

Answer 15

1. sterilization
2. disinfection
3. antisepsis (degermation)
4. decontamination (sanitization)

Question 16

What is microbial death?

Answer 16

The permanent termination of organisms vital processes

• permanent loss of reproductive capabilities

Question 17

What 5 factors affect the action of antimicrobial agents?

Answer 17

1. The number of microbes
   - higher load of contaminants takes longer to destroy.
2. The nature of the microorganisms in the population.
   - target population is a mixture of bacteria, fungi, spores and viruses
3. Temperature and pH of the environment.
   - can affect the mechanism of action of the agent used
4. The concentration (dose, intensity) of the agent
   - most disinfectants are more active at higher concentrations
5. The mode of action of the agent
   - How does it kill or inhibit the microbes>
6. The presence of solvents, interfering organic matter and inhibitors
   - saliva, blood and feces inhibit actions of disinfectants

Question 18

What are the 4 cellular targets of physical and chemical agents?

Answer 18

1. Cell wall
2. Cytoplasmic membrane
3. Cellular synthetic processes (DNA, RNA)
4. Proteins

Question 19

What agents are used for the cell wall?

Answer 19

Chemicals, detergents, alcohols

Question 20

What agents are used for the cytoplasmic membrane?

Answer 20

Detergents and alcohol

Question 21

What agents are used for cellular synthesis?

Answer 21

Formaldehyde, radiation and ethylene oxide

Question 22

What agents are used for proteins?

Answer 22

Moist heat, alcohol, phenolics

Question 23

What are examples of moist heat and the common temperature?

a method of physical control

Answer 23

Moist heat - hot water, boiling water or steam between 60C - 135 C

Question 24

What is dry heat?

a method of physical control

Answer 24

Dry heat- hot hair or an open flame which ranges from 160C - several thousand degrees C

Question 25

What is the difference between moist and dry heat in terms of methods

Answer 25

Moist- Operates at lower temperatures and shorter exposure times to achieve the same effectiveness as dry heat Dry heat - dehydrates the cell, denatures the protein , can oxidate a cell causes it to burn to ashes

Question 26

What are examples of moist heat?

Answer 26

boiling water , pasteurization, steam under pressure (autoclaving)

Question 27

What are examples of dry heat?

Answer 27

Incineration, hot air oven

Question 28

What are the affects of the cold?

Answer 28

To slow the growth of cultures, can preserve cultures (temp -70C to - 135C)

Question 29

Tell me about non-ionizing radiation.

Answer 29

Its most lethal from 240 to 280 nm. In order for it to DISINFECT properly, it must be directly exposed to it for full effect.

Question 30

Tell my about ionizing radiation

Answer 30

Highly effective way for STERILIZING materials that are sensitive to heat or chemicals Devices that use it are - gamma-ray machines containing radioactive cobalt - X ray machines similar to those used in medical diagnosis - cathoderay machines Items are placed in these machines for a short item with a carefully chosen dosage

Question 31

What is filtration?

Answer 31

Effective method to remove microbes from air and liquids. Fluid is strained through a filter with openings large enough for the fluid to pass through. Pores can prevent viruses or large proteins from passing

Question 32

Give examples of osmotic pressure.

Answer 32

Adding large amounts of salt or sugar to foods to create an hypertonic environment, drys out the bacteria (plasmolysis( and helps preserve food

Question 33

What are the three germicides and their meaning?

Answer 33

``` High-level germicide kill endospores (sterilization) ``` Intermediate - level (kill fungal but not bacterial, spores, resistant pathogens or viruses) Low-level- eliminate only vegetative bacteria, fungal cells and some viruses

Question 34

What is the difference between aqueous and tinctures?

Answer 34

Aqueous- chemicals dissolved in pure water as the solvent Tinctures- Chemicals dissolved in pure alcohol or alcohol - water mixtures

Question 35

Glutaraldehyde affects what type of macromolecules?

Answer 35

Proteins ; it disrupts the activity of enzymes and other proteins within the cell

Question 36

what four things are Soaps and quats commonly used for?

Answer 36

1. Sanitization of food preparation equipment 2. Disinfection of restrooms 3. Skin cleansing 4. Sanitization of the home

Question 37

Phenolics typically kill microbes by ______.

Answer 37

disrupting cell walls and membranes and in lower concentrations, they inactivate certain critical enzyme systems(denaturing metabolic enzymes)

Question 38

Which chemical is valuable for sterilization of heat-sensitive objects such as plastics, surgical and diagnostic appliances, and spices, but is more toxic than other available related gases? - propylene - ethylene oxide - chlorine - formaldehyde

Answer 38

ethylene oxide

Question 39

Which of the following heavy metals are still used in germicidal preparations? - copper - arsenic - gold - silver - zinc - mercury

Answer 39

silver & mercury

Question 40

Iodine compounds typically kill microbes by denaturing _____

Answer 40

enzymes

Question 41

Which two alcohols are effective in microbial control? - isopropyl - methyl - ethyl - butyl

Answer 41

isopropyl & ethyl

Question 42

True or false: Soaps and detergents are sufficient on their own for home cleaning, and additional antimicrobial agents are likely to lead to resistance in the microbes.

Answer 42

True

Question 43

What is a common use for chlorhexidine solutions? - sterilization - antisepsis - disinfection - filtration

Answer 43

antisepsis it is commonly used as an obstetrics antiseptic

Question 44

Chlorine compounds typically kill microbes by ______.

Answer 44

denaturing metabolic enzymes

Question 45

Temperature and radiation are two _______ methods used to control microbes.

Answer 45

physical

Question 46

An example of using dry heat to sterilize materials is the _____of loops and needles in the laboratory.

Answer 46

flaming

Question 47

Desiccation can preserve foods by reducing the availability of ____ to microbes for their metabolism.

Answer 47

water

Question 48

A technique in which heat is applied to liquids to kill potential agents of infection and spoilage is ___

Answer 48

pasteurization

Question 49

An effective method of controlling microbes in food products is ___

Answer 49

ionizing

Question 50

Ultraviolet radiation affects the _____ of cells.

Answer 50

DNA

Question 51

Which of the following are effects of ionizing radiation on food products?

Answer 51

Changes in texture of some foods Small decreases in thiamine Killing of bacterial pathogens

Question 52

Filtration has been used in what?

Answer 52

Decontamination of air Decontamination of milk products Water purification Sterilization of medical products