Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIO 246: Microbiology of Human Disease > Ch 9: Microbial Control > Flashcards

Ch 9: Microbial Control Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Why are Prions resistant to elimination?

A

Prions are simple; no genes; protein is already misfolded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why are Endospores resistant to elimination?

A

Endospores have an extremely tough spore coat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why are Mycobacterium resistant to elimination?

A

Mycobacterium has a waxy cell wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the levels of decontamination?

A
  1. Sterilization
    2a. Disinfection
    2b. Antisepsis
    3a. Sanitization
    3b. Degermation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is sterilization?

A

destruction or removal of ALL viable microbes including endospores and viruses from inanimate objects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Using an autoclave on Surgical/dental instruments is an example of what kind of decontamination?

A

sterilization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is disinfection?

A

destruction or removal of vegetative pathogens but not endospores (can also remove toxins) from inanimate objects/surfaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What kind of decontamination would wiping a countertop down w/ bleach be?

A

disinfection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is antisepsis?

A

destruction or inhibition of vegetative pathogens but not endospores from living tissues (skin & mucous membranes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What kind of decontamination would wiping your skin w/ an alcohol wipe (prior to needle injection) be?

A

Antisepsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is sanitization?

A

reduction in the number of microorganisms to acceptable levels on inanimate objects/surfaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

When dishes are washed with soap/detergent and warm/hot water in a restaurant, what kind of decontamination would this be?

A

sanitization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is degermination?

A

reduction in the number of microorganisms on living tissues (human skin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What kind of decontamination is washing hands after you have been in contact with fomites in public places and before you touch your eyes, nose or mouth?

A

degermination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

To reduce the number of foodborne microbes to acceptable levels on utensils in a restaurant, they are placed in the dishwasher. What level of decontamination is this?

A

sanitization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which list of microbes is correctly ordered from most resistant to decontamination to least resistant?

A) Bacterial endospore, protozoan cyst, enveloped virus
B) Protozoan cyst, enveloped virus, bacterial endospore
C) Bacterial endospore, enveloped virus, protozoan cyst
D) Enveloped virus, protozoan cyst, bacterial endospore
E) Protozoan cyst, bacterial endospore, enveloped virus

A

A) Bacterial endospore, protozoan cyst, enveloped virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the types of heat used to control microbes?

A

Dry and Moist Heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is moist heat?

A

Moist heat is used to denature and/or coagulate microbial proteins
- Inactivates enzymes; disrupts structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is dry heat?

A

Dry heat is used to dehydration cells, denature proteins, and oxidize (burn to ashes) biological molecules
- complete destruction of microbes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Why is an endospore tough to kill?

A

Endospore-forming bacteria are difficult to kill because of their tough spore coat and metabolic inactivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are two endospore forming bacteria and when are they resistant/weak to decontamination?

A

Bacillus & Clostridium
- In the endospore state they are thermoduric (resistant
to heat killing)
- in vegetative state they are easily killed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the types of moist heat that are used to decontaminate?

A

Boiling Water
Steam under pressure
Tyndallization
Pasteurization

23
Q

How is boiling water used to decon?

A

Form of moist heat decon

Decontamination achieved at 100 ˚C for 30 minutes
Kills most microbes including pathogens but not endospores

24
Q

How is steam under pressure used to decon?

A

Form of moist heat decon

Pressure above normal atmospheric will result in steam temperatures above 100˚C

  • 15 psi above normal = 121˚C
    e. g. autoclave & home pressure cooker

Effectively destroys endospores

Sterilizes inanimate objects/substances

25
Q

How is tyndallization used to decon?

A

Intermittent steam for 30-60 minutes over 3 days
- Used for heat-sensitive media or canned foods

This allows endospores to germinae after cooling, and then another cycle of steam kills vegetative cells

26
Q

How is pasteurization used to decon?

A

disinfection of beverages at 71.6 ˚C for 15 seconds

  • Ultra-pasteurization @ 134 ˚C for 1-2 seconds
  • Control milk-borne pathogens
27
Q

What are the types of dry heat used for decon?

A

hot air or flame

Hot Air: oven
- Effective at 150-180˚C for 2-4 hrs

Flame: incineration

  • Flame 1870˚C
  • Furnace 800-6500˚C
28
Q

Why is moist heat usually better at decon that dry heat?

A

To achieve the same level of decontamination, temperature and time of exposure for dry heat is greater than for moist heat

29
Q

How can colder temperatures be used to control microbial growth?

A

reduce metabolism and inhibit growth

- eg. refrigerate or freeze

30
Q

What are some other options for extending shelf life of a product besides refrigeration/freezing?

A

dehydration to remove water

lyophilization (freeze-drying)

hypertonic environments

31
Q

How does a hypertonic environment extend shelf life?

A 
High solute (salt, sugar) concentrations will inhibit microbial growth by increasing osmotic pressure
 - Bacteria will undergo plasmolysis
32
Q

What types of radiation can be used to decontaminate?

A

Ionizing and Non-ionizing radiation

33
Q

What is ionizing radiation?

A

gamma rays (radioactive isotopes) can penetrate thru solid objects/layers and damage microbial DNA

34
Q

What is a benefit of ionizing radiation?

A

alternative sterilization method for materials sensitive to heat or chemicals such as foods (fruits, vegetables, meats)

35
Q

What is non-ionizing radiation?

A

ultraviolet (UV) rays cannot penetrate and only affect upper surface of objects to damage microbial DNA

36
Q

How can non-ionizing radiation be used to decontaminate?

A

germicidal lamps are used for disinfection of inanimate surfaces, air, or water can be used to inactivate protozoan cysts but not bacterial endospores

37
Q

What method can be used to physically remove microbes and endospores from fluids?

A

filtration

38
Q

What are the types of filtration?

A

HEPA filters are used to purify air

Liquid filters are used to sterilize heat-sensitive liquids, such as serum, vaccines, media

39
Q

What physical method of control would be most useful against airborne Bacillus anthracis endospores in an office space?

A. Incineraton
B. Pasteurization
C. Non-ionizing radiation
D. HEPA filtration
E. Tyndallization
A

D. HEPA filtration

40
Q

An autoclave is a sterilizer that uses:

A. Dry heat
B. Ionizing radiation
C. High speed air flow
D. Extreme cold temperatures
E. Steam under pressure
A

E. Steam under pressure

41
Q

What halogens are used to control microbial growth?

A

chemical methods of microbial control

halogens such as chlorine and iodine are used as disinfectants or antiseptics

42
Q

How do halogens like chlorine and iodine work?

A

disrupt sulfhydryl groups in amino acids and inactivate microbial enzymes and metabolism

43
Q

What is betadine?

A

Betadine is an iodine solution that is used on skin prior to catheter insertion or surgical incision

44
Q

What phenolic agents are used to control microbial growth?

A

chlorhexidine and triclosan are phenolic agents added to soaps that disrupt cell walls and membranes and cause microbial cell lysis

45
Q

What alcohols are used to control microbial growth?

A

ethanol and isopropanol are alcohols that are used as germicidal agents that dissolve membrane lipids, disrupt cell surface tension and denature proteins

46
Q

At what concentration can alcohols be used for antisepsis?

A

70%

47
Q

What is hydrogen peroxide?

A

hydrogen peroxide is an effective antiseptic and disinfectant

48
Q

How does hydrogen peroxide work? What can it be used as?

A

forming hydroxyl free radicals with biological molecules

Can be used as:

  • Skin and wound cleaner
  • Quick method for disinfecting medical equipment
49
Q

In August 2005, 3800 patrons at Seneca Lake Park (NY) “sprayground” came down with diarrhea, vomiting, fever, cramps. The cause was discovered to be Cryptosporidium parvum, a protozoan parasite. Inspectors confirmed that chlorination and filtration were standard procedures for treatment of the recirculated water. Why were these methods unsuccessful in eliminating this pathogen? What type of water treatment could be added to help?

A

These methods were unsuccessful b/c the protozoan parasite formed a cyst resistant to these methods of decon

Ionizing radiation could be used

50
Q

In 2001, a letter containing a mysterious powder was delivered to the Hart Office Building in Washington, DC. It was discovered that this letter contained a deadly pathogen, Bacillus anthracis. What method of decon was used?

A

The office was cleared and the EPA used HEPA filtration and chlorine dioxide gas for treatment.

51
Q

What was done to ensure decon worked after the anthrax letter incident?

A

Paper strips containing a non-pathogenic bacterium were placed throughout the office. After decontamination, the strips were collected and cultured. No bacterial growth showed the decontamination procedure worked and workers could safely return to the building.

52
Q

Triclosan is a(n) ________ compound that is used as an antibacterial agent in hand soap, detergents, and toothpaste.

A

phenolic

53
Q

Which of the following uses a halogen for microbial control?

A. Water is used to rinse off dishes in the sink
B. Isopropanol is used to control skin microbes before
needle injection
C. Surgeons scrub their hands with soap containing
chlorhexidine
D. Medical equipment can be sterilized by soaking in
hydrogen peroxide
E. A swimming pool is chlorinated to inhibit microbial
growth

A

E. A swimming pool is chlorinated to inhibit microbial

growth

BIO 246: Microbiology of Human Disease (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions