Micro Study Guide Questions - Part 3 - Controlling Microbes

Front 1

Approaches to control:

List 4 Physical Methods

Back 1

1. Heat

2. Irradiation

3. Filtration

4. Mechanical removal

Front 2

Approaches to Control:

List 1 Chemical Methods and what it depends on...

Back 2

- antimicrobial chemicals

Depends on:

-circumstances

-degree of control required

(may be a combination of both)

Front 3

List the 6 methods of controlling microbes:

Back 3

1. Sterilization

2. Disinfection

3. Decontamination

4. Sanitizing

5. Pasteurization

6. Preserving

Front 4

Which ones have to to with food?

Back 4

Pasteurization

Preserving

Front 5

Which ones have to do with cleaning (sort of)

Back 5

Disinfection

Decontamination

Sanitizing

Front 6

What is sterilization?

Back 6

removal of all microorganisms

Front 7

Sterilization is free of microbes including _____________ and ____________

(but does not consider _____________)

Back 7

viruses; endospores

prions

Front 8

Disinfection is:

Back 8

the elimination of all or most pathogens

(some viable pathogens may remain)

Front 9

Decontamination is:

Back 9

reducing pathogens to levels considered to be safe to handle

Front 10

Sanitizing is:

Back 10

substantially reduced microbial population that meets accepted health standards

(not a specific level of control)

Front 11

Pasteurization is:

Back 11

brief heating to:

-reduce number of spoilage organisms

-destroy pathogens

Front 12

Preserving is:

Back 12

Process of delaying spoilage of foods and other perishable products

Front 13

Situations where you might use:

Sterilization:

Back 13

-surgery

-some lab procedures

*autoclaving

Front 14

Situations where you might use:

Disinfection:

Back 14

Disinfectants:

-used on inanimate objects (ex. countertops)

-cide = to kill

-may be called biocides, germicides, bactericides

Antiseptics:

-used on living tissue

Front 15

Situations where you might use:

Decontamination:

Back 15

If you have hazardous waste / materials

-Example: Anthrax, Asbestos

Front 16

Situations where you might use:

Sanitizing:

Back 16

Examples -

-we sanitize dishes when we use a dishwasher

-baby bottles and accessories are sanitized in a machine

Front 17

Situations where you might use:

Pasteurization:

Back 17

-Food (milk, some eggs, some vinegar)

-inanimate objects

*often used for heat-sensitive materials that cannot withstand prolonged exposure to high temperatures

Front 18

Situations where you would use:

Preservation

Back 18

Food!

* conditions may require adjustment

* add bacteriostatic (growth-inhibiting) preservatives

*can, freeze, salt-cure, dry/dehydrate

Front 19

Microbial control methods are highly variable.

Effectiveness of treatment depends on:

(list 4 things)

Back 19

1. # of microbes

2. Environment (organic matter, temperature, biofilm?

3. Time of exposure

4. Microbial characteristics

Front 20

Actions of Microbial Control Agents:

Three ways to harm them:

Back 20

1. alteration of membrane permeability

2. damage to proteins (enzymes)

3. damage to nucleic acids

Front 21

What is the most important step in stopping the spread of many infections diseases

Back 21

washing hands with soap

Front 22

What type of removal action is washing your hands with soap?

Back 22

mechanical removal

Front 23

What is the more effective hand-drying method:

Paper towels or hot-air dryer?

Back 23

paper towels

Front 24

What is a nosocomial infection?

Back 24

hospital-related...

usually picked up in the hospital

Front 25

What are three reasons why nosocomial infections are common in hospitals?

Back 25

1. Patients are more susceptible to infection

(compromised immune systems, invasive procedures, etc.)

2. Pathogens are more likely found in hospital settings

-(feces, urine, respiratory droplets, bodily secretions)

3. hospitals have high concentrations of antibiotics ----> resistant pathogens

Front 26

In the Microbiology Lab:

Name 2 areas in which microbial contamination needs to be eliminated:

Back 26

1. experimental samples

2. environment

Front 27

What two things / methods are necessary for growth and to prevent contamination of samples, self, and lab?

Back 27

1. aseptic technique

2. sterile media

Front 28

Contaminated materials are decontaminated by putting them in an __________.

Back 28

Autoclave

Front 29

An autoclave uses high pressure saturated STEAM.

Temp =

Time =

Back 29

121 d. Celsius

15 - 20 min.

Front 30

CDC guidelines:

Biosafety Levels range for:

Back 30

BSL 1- microbes not known to cause disease

to

BSL 4 - lethal pathogens for which no vaccine or treatment exists

Front 31

Perishables -

retain quality longer when contaminating microbes are either (3 things)

Back 31

1. destroyed

2. inhibited

3. removed

Front 32

Perishables:

What is the most common and reliable mechanism?

Back 32

Heat

*can alter flavor and appearance of products

Front 33

Irradiation has been approved to treat certain ___________.

Back 33

foods

Front 34

Chemical additives can prevent

Back 34

spoilage

Front 35

Water Treatment Facilities use _________________ to disinfect water.

Back 35

chlorine

Front 36

Selection of antimicrobial procedure:

-Complicated...

-Ideal method does not exist

-Each has drawbacks and procedural parameters

Choice depends on: (4 things)

Back 36

1. type and # of microbes

2. Environmental conditions

3. Risk of infection

4. Composition of infected item

Front 37

What is the most critical consideration when choosing an antimicrobial procedure?

Back 37

Is it resistant?

Front 38

Why is this microorganism difficult to get rid of?

What are the means you could use to do so?

Bacterial endospores

Back 38

-highly resistant

-only destroyed by extreme heat or extreme chemicals

Front 39

Why is this microorganism difficult to get rid of?What are the means you could use to do so?

Protozoan cysts & oocysts

Back 39

-resistant to disinfectants

-excreted in feces

-cause diarrheal disease if ingested

Front 40

Why is this microorganism difficult to get rid of?What are the means you could use to do so?

Mycobacterium species

Back 40

-waxy cell wall makes it resistant to many chemical treatments

Ex. - leprosy (Hansen's disease)

Front 41

Why is this microorganism difficult to get rid of?What are the means you could use to do so?

Pseudomonas species

Back 41

-resistant to (and can actually grow in) some disinfectants

(smells like Juicy Fruit gum)

Front 42

Why is this microorganism difficult to get rid of?What are the means you could use to do so?

Naked Viruses

Back 42

-no lipid envelope

-more resistant to disinfectants

Front 43

What affects the TIME it takes for heat and chemicals to kill microorganisms?

Back 43

population size

Front 44

Larger populations of microbes require ____________ time to destroy

Back 44

more

Front 45

Removing organisms by _______ reduces time it takes to kill them.

Back 45

washing

Front 46

What is the Decimal reduction time

(aka. D value)

And what does it do?

Back 46

-Time it takes to kill 90% of population under specific conditions

-gauges commercial effectiveness

Front 47

Environmental Conditions:

What things can interfere with heat penetration and action of chemicals?

three things

Back 47

1. pH

2. temperature

3. organic materials

Front 48

Most chemicals are more effective at a ____________ temp and ________ pH.

Back 48

higher temp

lower pH

Front 49

Risk for Infection:

Medical instruments are categorized according to risk for transmitting infectious agents.

Define critical items:

Define Semi-critical instruments:

Back 49

Critical: come in contact with body tissue

-must be sterile

-needles and scalpels, etc.

Semi-Critical: contact mucous membranes but do not penetrate body tissue

-must be free of viruses and vegetative bacteria

-few endospores blocked by mucous membranes

-includes endoscopes and trach tubes

Front 50

Non-Critical instruments include:

Back 50

stethoscope

BP cuff, etc.

Front 51

Composition of the item:

Some sterilization and disinfection methods are inappropriate for certain items:

1. Heat is inappropriate for:

2. Irradiation provides alternative, but damages some types of:

3. Moist heat, liquid chemical disinfectants cannot be used to treat:

Back 51

1. plastics

2. plastic

3. moisture-sensitive material

Front 52

What type of test method tests disinfectants and antiseptics?

Back 52

Use-Dilution test

(metal cylinders dipped in test bacteria, dried, placed in disinfectant.)

Front 53

What test method evaluates the efficacy of chemical agents (antibiotics)

Back 53

Disk-Diffusion

Front 54

What type of organisms would you use filtration on?

Back 54

Guardia

(filtration retains bacteria)

Front 55

Heat as a control:

Benefits of heat treatment:

Back 55

-reliable

-safe

-relatively fast

-inexpensive

-non-toxic

Front 56

Heat can be use to _____________ or to ____________.

Back 56

sterilize

disinfect

Front 57

Heat methods include (2)

Back 57

1. moist heat

2. dry heat

Front 58

Moist heat irreversibly _____________ __________.

Back 58

denatures proteins

Front 59

Moist Heat:

Boiling destroys most microorganisms and viruses.

What does boiling NOT sterilize?

Back 59

endospores

Front 60

Moist Heat:

Pasteurization reduces ___________ and increases ______________.

Back 60

microorganisms

shelf-life

Front 61

Moist Heat:

Pasteurization:

HTST =

UHT =

Back 61

HTST = High-Temp/Short-Time

UHT = Ultra High Temp (Ultra pasteurization)

Front 62

Moist Heat:

An autoclave uses __________ ____________ to sterilize

Back 62

pressurized steam

Front 63

Does autoclaving kill endospores?

Back 63

YES, it does!

Front 64

Can autoclaving destroy prions?

Back 64

They believe so at 132 d. Celsius for 1 hour

Front 65

Dry Heat:

Is it more or less effective than moist heat?

Back 65

LESS effetive

Front 66

Dry heat requires ____________ time and _________ temperatures.

Back 66

more time

higher temps

Front 67

Dry Heat:

Incinerator is a method of dry heat _____________.

Back 67

sterilization

Front 68

Dry Heat:

Incinerators:

1. How do they work?

2. What are they used for?

Back 68

1. oxidizes cell to ashes

2. to destroy:

-medical waste

-animal carcasses

-sterilize lab inoculation loop

Front 69

Irradiation works by destroying:

(Ionizing)

Back 69

DNA

(removes electrons from atoms)

Front 70

Irradiation is used to sterilize heat-sensitive materials including:

Irradiation is IONIZING radiation (like X-rays)

Back 70

-medical equipment

-surgical supplies

-medications

-some food

Front 71

High Pressure Pasteurization is used in the production of commercial _____________.

It destroys microbes by ___________ ___________.

Back 71

foods

denaturing proteins

Front 72

Ultra-Violet Radiation is ______________ radiation

Back 72

non-ionizing

Front 73

How does UV radiation affect microorganisms?

Back 73

-destroys microbes directly

-damages DNA

Front 74

Where is UV Radiation used?

Back 74

to destroy microbes in:

-air

-water

-on surfaces

Front 75

What limits the effect of UV radiation?

Back 75

-thin films or coverings

(because UV radiation has poor penetrating power)

Front 76

How do alcohols affect microbes?

Back 76

-kill enzymes by desiccation (coagulate essential proteins)

-kill vegetative bacteria and fungi

*NOT reliable against endospores & some naked viruses

Front 77

Alcohols are commonly used as: (2)

Back 77

1. antiseptics

2. disinfectants

Front 78

Limitations of alcohol: (2)

Back 78

1. evaporates quickly (limits contact time)

2. can damage rubber, plastics, etc.

Front 79

What are the classes of chemical agents used in controlling microbes?

Back 79

1. alcohol

2. aldehydes

3. biguanides

4. ethylene oxide

5. halogens

6. metal compounds

7. ozone

8. peroxygens

9. phenolic compounds

10. quaternary ammonium compounds

Front 80

Which gaseous sterilant is used on surgical equipment?

Back 80

Ethylene oxide

Front 81

What are the dangers of working with this reagent?

Back 81

Ethylene oxide is mutagenic and potentially carcinogenic

Front 82

What is a common halogen often used in the home, food industry, hospital, and lab environment?

Back 82

Chlorine

(other one is iodine)

Front 83

What class is Chlorohexidine ad most antiseptics (including mouthwash) in?

Back 83

Biguanides

Front 84

What metal compound is still sometimes used as an antiseptic?

Back 84

silver (silver nitrate eyedrops, silver sulfadiazine)

Front 85

Miscellaneous:

Food preservation:

Refrigeration inhibits growth of pathogens and spoilage organisms by:

Back 85

slowing or stopping enzyme reactions

(psychrophilic and psychrotrophic organisms can still grow)

Front 86

Freezing preserves by:

Back 86

stopping all microbial growth

*many can still survive and can grow once thawed

Front 87

Is Staph aureus effected by a salty environment?

Back 87

Staph aureus loves a high salt environment and is happy there...

Therefore it can still grow in foods that have been preserved by salting

Front 88

How does salting of food preserve it?

Back 88

increases environmental solutes...

-causes cellular plasmolysis (shrinkage of bacterial cell as water leaves)