Chapter 7 Physical and chemical agents Flashcards Preview

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Flashcards in Chapter 7 Physical and chemical agents Deck (53):
1

What is the destruction or removal of vegetative pathogens but not bacterial endospores only used on inanimate objects (non-living surfaces)?

disinfection

2

Can sterilization be used on the skin?

no
(inanimate)

3

Which Microbial control method is the complete removal or destruction of all viable microorganisms that is used on inanimate objects? (free of life, free of viruses)

sterilization

4

What is antisepsis?
(animate)

something used that destroys most organisms, pathogens on living surface. (skin)

5

define disinfectant

an antimicrobial that kills bacteria, fungi, and viruses
(but not endospores)

6

give 2 examples of disinfectants

bleach, hydrogen peroxide

7

Name the three different types of Microbial control methods (agents)

*Physical agents
*Chemical agents
*Mechanical agents

8

What type of microbial control agents are heat and radiation?

physical agents

9

What is sanitization?

general decrease of bacterial load and debris or disinfection that meets specific public health standards
-sanitizer

10

Define degerming

mechanically removing some microorganisms

11

If a chemical is considered a bacteriocidal, what does it do?

kills microorganisms

12

If a chemical is Bacteriostatic what does it do?

inhibit growth, halt bacteria from reproducing

13

List the 4 things that antimicrobial agents target (in bacteria)

* Cell wall (hypotonic)
* Cell membrane or envelope
*** Proteins (biggest target!)
* Nucleic Acids

14

On the list of most susceptible to most resistant, what was most susceptible to antimicrobial agents and what was most resistant?

Enveloped viruses = Most susceptible
Bacterial endospores = Most resistant

15

Which is more resistant (closer to bottom of list) to antimicrobial agents, Non-enveloped viruses or Mycobacteria?

Mycobacteria

16

Which is more resistant (closer to bottom of list) to antimicrobial agents, Fungi or Cysts of protozoa?

Cysts of protozoa

17

if something is "sterile", does that mean it is safe? why?

No, that means it is free of life not free of molecules/chemicals

18

Do x-rays penetrate through bone?

no

19

What has to happen for a material to be classified as radioactive?

it has to be continually giving off rays/particles

20

What two types of rays/particles can remain/stay behind after radiation?

*alpha
*beta

21

Which type of rays associated with radiation go through and then disappear?

gamma rays

22

Is Uranium radioactive and why or why not?

yes, because it continues emitting particles like Alpha and Beta

23

Define pasteurization

heating up to kill pathogens below boiling point

24

List the 5 methods of Physical Control

1. Heat - moist and dry
2. Cold Temperatures
3. Desiccation
4. Radiation
5. Filtration

25

Give the temperature, the time, and what happens/how to do it for the following.
Moist Heat:
Dry Heat:

Moist heat: lower temps (120-134 degrees C)
shorter exposure time ( 3-15 minutes)
Coagulation and denature of proteins
Dry Heat: mod-high temp (121 C-170 degrees C)
longer exposure time (60-600 minutes)
dehydration, alters protein structure, incineration

26

Name the physical control method that involves steaming at 121 degrees C and sterilization
(they do this to our lab coats)

Autoclaving

27

How hot must it be to boil and how long? is this disinfection or sterilization?

100 degrees C for 30 minutes
disinfection

28

Camplyobacter, Listeria, Salmonella, and Mycobacteria can withstand which type of disinfection?
(hint: spoiled milk)

Pasteurization

29

When you raise a liquids temperature to 134 degrees Celsius for 1-2 seconds, what type of sterilization is this?

Ultra High Temperature Sterilization

30

How long must you expose something to Dry Heat and what temp in F?

1-4 hours
350 degrees F
Sterilization

31

What temperature in celsius must something be incinerated at? incineration?

~5000 C

32

What are Drying, freezing, and Lyophilization considered?
(hint:what happens to bacteria when frozen)

Bacteriostatic processes
*generally not considered disinfection

33

What is associated with UV ray exposure that changes your AT sequences to TT sequences?

Thymine Dimer

34

When are there DNA breakages, with Non-Ionizing Radiation or Ionizing radiation?

Ionizing Radiation

35

Are X rays and Gamma rays Non-Ionizing radiation or Ionizing radiation?

Ionizing Radiation

36

Name the two types of filtration

* Liquid (pore size)
* Air (HEPA)

37

What does HEPA stand for with Air Filtration?

High-efficiency Particulate Air Filters

38

give the 3 levels of chemical decontamination

* High-level
* Intermediate-level
* Low-level

39

Which level of chemical decontamination will kill all organisms except endospores? (endospore examples: fungal spores, mycobacterium)

Intermediate-level

40

Which level of chemical decontamination will kill endospores and can sterilize if used correctly?

High-level

41

What will a Low-level chemical decontaminate eliminate?

vegetative bacteria, vegetative fungal cells, and some viruses

42

Filtration is a mechanical removal method.
true or false?

true

43

A chemical agent as a microbial control method can be either ___ or ______

gas or liquid

44

Which chemical control type is a derivative of Phenol and is often used for surgical and hospital microbial control procedures. This chemical works against Gram-positive staphylococci and streptococci found in nurseries?

Bisphenols

45

What part of bacteria do Biguanides primarily affect? and what are they especially effective against?

*bacterial cell membranes
* gram-positive bacteria
also effective against most gram-negative (except pseudomonads)

46

What are Iodine and Chlorine, and what does Iodine do to bacterial cells?
what kinds of things does Iodine kill?

*Halogens
* Iodine impairs protein synthesis and alters cell membranes by forming complexes with amino acids and unsaturated fatty acids
* active against all kinds of bacteria
many endospores
fungi
some viruses

47

What can alcohol effectively kill and how is this done?

bacteria
fungi
enveloped viruses
( cannot kill endospores or non-enveloped viruses )
* denatures proteins, disrupts membranes, dissolves many lipids including lipid component of enveloped viruses

48

What is phenol and what is susceptible to it due to it's ability to injure lipid-containing plasma membranes resulting in leakage of cellular contents?

phenol is carbolic acid
* the cell wall of mycobacteria ( TB and leprosy are rich in lipids)

49

What are Quats?
what are they effective against?

Quaternary Ammonium compounds
* cationic detergent. most widely used surface-active agents
* strongly bacteriocidal against gram-positive bacteria, not quite as effective against gram-negative
*fungicidal, amebicidal, virucidal against enveloped viruses
Do not kill endospores or mycobacteria

50

Name the most effective microbials?

Aldehydes
(formaldehyde, glutaraldehyde)

51

How do Aldehydes work?

inactivate proteins by forming covalent cross-links with organic functional groups on proteins

52

what is plasma?

the fourth form (state) of matter

53

What are peroxygens?

a group of oxidizing agents
(includes hydrogen peroxide and peracetic acid)