Chapter 7 Physical and chemical agents

Question 1

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

Answer 1

disinfection

Question 2

Can sterilization be used on the skin?

Answer 2

no

inanimate

Question 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)

Answer 3

sterilization

Question 4

What is antisepsis?

animate

Answer 4

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

Question 5

define disinfectant

Answer 5

an antimicrobial that kills bacteria, fungi, and viruses

but not endospores

Question 6

give 2 examples of disinfectants

Answer 6

bleach, hydrogen peroxide

Question 7

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

Answer 7

• Physical agents
• Chemical agents
• Mechanical agents

Question 8

What type of microbial control agents are heat and radiation?

Answer 8

physical agents

Question 9

What is sanitization?

Answer 9

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

Question 10

Define degerming

Answer 10

mechanically removing some microorganisms

Question 11

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

Answer 11

kills microorganisms

Question 12

If a chemical is Bacteriostatic what does it do?

Answer 12

inhibit growth, halt bacteria from reproducing

Question 13

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

Answer 13

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

Question 14

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

Answer 14

Enveloped viruses = Most susceptible

Bacterial endospores = Most resistant

Question 15

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

Answer 15

Mycobacteria

Question 16

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

Answer 16

Cysts of protozoa

Question 17

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

Answer 17

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

Question 18

Do x-rays penetrate through bone?

Answer 18

no

Question 19

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

Answer 19

it has to be continually giving off rays/particles

Question 20

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

Answer 20

• alpha

* beta

Question 21

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

Answer 21

gamma rays

Question 22

Is Uranium radioactive and why or why not?

Answer 22

yes, because it continues emitting particles like Alpha and Beta

Question 23

Define pasteurization

Answer 23

heating up to kill pathogens below boiling point

Question 24

List the 5 methods of Physical Control

Answer 24

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

Question 25

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

Answer 25

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

Question 26

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

Answer 26

Autoclaving

Question 27

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

Answer 27

100 degrees C for 30 minutes | disinfection

Question 28

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

Answer 28

Pasteurization

Question 29

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

Answer 29

Ultra High Temperature Sterilization

Question 30

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

Answer 30

1-4 hours 350 degrees F Sterilization

Question 31

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

Answer 31

~5000 C

Question 32

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

Answer 32

Bacteriostatic processes | *generally not considered disinfection

Question 33

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

Answer 33

Thymine Dimer

Question 34

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

Answer 34

Ionizing Radiation

Question 35

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

Answer 35

Ionizing Radiation

Question 36

Name the two types of filtration

Answer 36

* Liquid (pore size) | * Air (HEPA)

Question 37

What does HEPA stand for with Air Filtration?

Answer 37

High-efficiency Particulate Air Filters

Question 38

give the 3 levels of chemical decontamination

Answer 38

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

Question 39

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

Answer 39

Intermediate-level

Question 40

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

Answer 40

High-level

Question 41

What will a Low-level chemical decontaminate eliminate?

Answer 41

vegetative bacteria, vegetative fungal cells, and some viruses

Question 42

Filtration is a mechanical removal method. | true or false?

Answer 42

true

Question 43

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

Answer 43

gas or liquid

Question 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?

Answer 44

Bisphenols

Question 45

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

Answer 45

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

Question 46

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

Answer 46

*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

Question 47

What can alcohol effectively kill and how is this done?

Answer 47

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

Question 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?

Answer 48

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

Question 49

What are Quats? | what are they effective against?

Answer 49

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

Question 50

Name the most effective microbials?

Answer 50

Aldehydes | formaldehyde, glutaraldehyde

Question 51

How do Aldehydes work?

Answer 51

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

Question 52

what is plasma?

Answer 52

the fourth form (state) of matter

Question 53

What are peroxygens?

Answer 53

a group of oxidizing agents | includes hydrogen peroxide and peracetic acid