Premed - Lecture 7. Physical And Chemical Control Of Microbes

Front 1

Define: Sterilization

Back 1

Killing / removing all microorganisms including spores

Front 2

Define: Disinfection

Back 2

Killing of many, but not all microbes. Reducing the number of bacteria to low level that disease is unlikely to occur (used on inanimate objects).

Front 3

Define: Sanitization

Back 3

Reducing microbial contaminate to a safe level

Front 4

Define: Asepsis

Back 4

Absence of pathogenic microbes

Front 5

Define: Sepsis

Back 5

Presence of pathogenic microbes

Front 6

Define: Antiseptic

Back 6

chemicals applied to body surfaces to destroy or inhibit vegetative pathogens

Front 7

Define: Antibiotics

Back 7

Products of microbes which inhibit other microbes. Some of htem are safe enough to be taken orally / treat human infections

Front 8

Define: Biocide

Back 8

General term used for a chemical that has a broad spectrum activity

Front 9

Define: Static

Back 9

Chemical that inhibits multiplication but does not kill

Front 10

Examples of Static:

Back 10

Bacteriostatic, Fungistatic (reaction is reversible)

Front 11

Define: Cidal

Back 11

Kills microbes

Front 12

Examples of Cidal:

Back 12

Bacteriocidal, fungicidal, sporocidal (Not reversible)

Front 13

Define: Microbial Death

Back 13

Permenant Loss of reproductive capability, even under optimum growth conditions.

Front 14

What is around a naked virus?

Back 14

Protein Coat

Front 15

What is around an enveloped virus?

Back 15

Lipids.

Front 16

What is more resistant to detergents (naked or enveloped?)

Back 16

Naked is more resistant

Front 17

What is the target of action (4 steps)

Back 17

1. cell wall
2. cell membrane
3. protein/ nucleic acid synthesis
4. interfere with protein function (denature proteins)

Front 18

3 ways to achieve killing or removing microbes?

Back 18

1. Physical (heat, radiation)
2. Chemical (gases and liquids)
3. Mechanical (filteration)

Front 19

What is more effective? Moist or Dry heat?

Back 19

Moist Heat.

Front 20

Three 3 ways that Moist Heat is used:

Back 20

1. Boiling
2. Pasteurization
3. Tyndallization

Front 21

Define: Boiling

Back 21

Boil at atmospheric pressure (100C) at sea level.
Can kill vegetative cells in 10 min but not spores.
Not a means of sterilization

Front 22

Define: Pasteurization

Back 22

Aim to kill pathogenic bacteria in milk and some canned foods.
62C for 30 min, followed by rapid cooling (or flash method which is 72 C for 15 min and then rapid cooling).

Front 23

Define: Tyndallization:

Back 23

Intermittent boiling.
Can attain sterility

Front 24

Define: Autoclaving:

Back 24

Boil under pressure (15 pounds per square inch).
A pressure cooker (121 C, 20 min)
Kills all including spores

Front 25

What does dry heat do to proteins?

Back 25

Denatures proteins.

Front 26

Dry Heat incineration includes 2 things:

Back 26

Direct flaming and dry hot air.

Front 27

Define: Direct flaming:

Back 27

Used to sterilize heat resistant materials for immediate use.

Front 28

Define: Dry hot air:

Back 28

In dry oven
Head resistant materials like glassware can be sterilized by dry heat.

Front 29

Which takes longer? Dry or moist heat?

Back 29

Dry Heat takes longer.

Front 30

What does cold do to microbes?

Back 30

Retards microbal activities
refridgeration temerature/ deep freezing

Front 31

Desiccation means to

Back 31

reduce the amount of water
food preservation

Front 32

How are microbes affected with desiccation?

Back 32

Microbes differ in sensitivty to desiccation

Front 33

Define: Lyophilization

Back 33

Drying in a frozen state
Preserve microbes for many years

Front 34

2 types of radiation used ?

Back 34

Ionizaing Radiation
Non-Ionization radiation

Front 35

Define: Ionizing Radiation:

Back 35

x-rays, gamma, high speed electrons
use to sterilize head sensative materials (syringes, gloves)

Front 36

Non-ionizing radiation:

Back 36

UV light, causes mutation in DNA
Destroys DNA forming bonds
Most lethal (240-280nm)
poorly penetrates objects
Used to sterilize air, operation room, surfaces, treatment of drinking water.

Front 37

Define: Sonication

Back 37

Sound waves
high frequency sound beyond the sensitivity to the human hear
used in dental practices

Front 38

Define: Filtration

Back 38

- mechanical removal using filers
- sterilize heat sensitive liquids (like enzymes, solutions for Intravenus administration)

Front 39

What are the most common bacterial filters?

Back 39

Nitrocellulase membranes
(pore size 0.22nm)

Front 40

Chemical agents are group according to their

Back 40

Mode of Action

Front 41

Disruption of Cell Membrane means....

Back 41

dissolve phospholipid bilayer
(ie. alcohol as antiseptic)

Front 42

Damage to DNA means...

Back 42

DNA reactive chemicals are capable of forming bonds the bases in DNA.
(Many dyes etc).

Front 43

What are agents that are active on the cell membrane?

Back 43

Lipids

Front 44

Denaturing proteins takes place with which elements?

Back 44

Halogens:
Flourine, Bromine, Chlorine, Iodine

Front 45

Other denaturing proteins also take place in (which elements) :

Back 45

Heavy Metals (silver nitrate)
(prevent eye infection in new born babies from gonoccal infections)

Front 46

Hydrogenperoxide is:

Back 46

antiseptic to clean wounds and contact lenses

Front 47

Ethylene Oxide is

Back 47

Gas used to sterilize heat sensative medical materials (gloves, syringes)

Front 48

Chemicals with surface action are

Back 48

detergents, soaps