Microbiology Chapter 9: Controlling Microbial Growth In The Environment

Front 1

Sterilization

Back 1

Destroy ALL microbial forms

Front 2

Commercial sterilization

Back 2

Purpose of removing MOST pathogenic microbes

Front 3

Antisepsis

Back 3

use on skin to destroy MOST harmful microbes. Kills vegetative microbes, can be used as a disinfectant

Front 4

Disinfection

Back 4

Destroy MOST microbes on inanimate objects

Front 5

Degerming

Back 5

Localized, isolated antisepsis with antiseptic (alcohol pad before vaccine)

Front 6

Sanitation

Back 6

Chemical rinse post-wash of silverware, public setting

Front 7

Pasteurization

Back 7

heating to kill majority of microbes--for liquid consumption.

Front 8

'cidal

Back 8

killing, in theory

Front 9

'static

Back 9

growth inhibited (mainly antibiotics)

Front 10

What affects the efficacy rate of a microbial control method?

Back 10

Site to be treated
Susceptibility and format of microorganism
Environmental conditions
Time
Load

Front 11

Efficacy rate:
Site to Be Treated

Back 11

Porous?
How will agent affect surface?

Front 12

Efficacy Rate:
Susceptibility and format of microorganism

Back 12

Vegetative?
Endospore?
Enveloped/nonenveloped virus? (Nonenveloped = harder to treat)

Front 13

Efficacy rate:
Environmental conditions

Back 13

Tris buffer: temp impacts pH
temp
pH

Front 14

Efficacy rate:
Time

Back 14

Not instant
Amount of time antimicrobe is left on micobes before wiping clean

Front 15

Efficacy Rate:
Load

Back 15

More antimicrobial stuff is better

Front 16

Efficacy rate:
Site to Be Treated

Back 16

Porous?
How will agent affect surface?

Front 17

Efficacy Rate:
Susceptibility and format of microorganism

Back 17

Vegetative?
Endospore?
Enveloped/nonenveloped virus? (Nonenveloped = harder to treat)

Front 18

Efficacy rate:
Environmental conditions

Back 18

Tris buffer: temp impacts pH
temp
pH

Front 19

Efficacy rate:
Time

Back 19

Not instant
Amount of time antimicrobe is left on micobes before wiping clean

Front 20

Efficacy Rate:
Load

Back 20

More antimicrobial stuff is better

Front 21

How physical and chemical agents affect their cellular targets:
Cell wall

Back 21

Peptidogllycan
- Prevent synthesis, break down cell wall

Front 22

How physical and chemical agents affect their cellular targets:
Cell Membrane

Back 22

Interrupt lipid bilayer, bulky with hydrophobic

Front 23

How physical and chemical agents affect their cellular targets:
RNA & DNA

Back 23

UV mutagenizes
Analogs incorporates something that looks right but isn't

Front 24

How physical and chemical agents affect their cellular targets:
Proteins

Back 24

Heat: denatures
Chemical: unfolds
Block their synthesis

Front 25

Physical Agents

Back 25

Dry heat sterilization
Moist heat sterilization

Front 26

Dry heat sterilization: incineration

Back 26

Flame - aseptic technique
Bunsen Burners & incinerators
Hospital Waste

Front 27

Dry heat sterlization:
Dry autoclave & dry ovens

Back 27

Empty bottles and pipettes
Dry: sterilize before use (pipet tips)
Wet: waste
Dry oven: sterilize things that would not do well in moist/get ruined (ex: fly tubes or OF glucose tubes)

Front 28

Moist heat sterilization: More effective because...

Back 28

Shorter period and lower temperature and wetness

Front 29

Moist heat sterilization:
Steam sterilization under pressure

Back 29

Autoclave media (121C, 15 psi/inch2)

Front 30

Moist heat sterilization:
Boiling water, pasteurization

Back 30

disinfection

Front 31

Moist heat sterilization:
Cold & dry: lyophilization

Back 31

Remove all water from something
Space food
Cold reduces metabolism
Dessication
food preservation
Strokes suspend further damage

Front 32

Moist heat sterilization:
Ionizing radiation, sterilization

Back 32

Sterilizing: x-ray, gamma ray, cathoid rays
More severe: cause DNA breakage
Cold sterilization:
- Meat preservation
- Drug treatment

Front 33

Moist heat sterilization:
Non-ionizing radiation, disinfection

Back 33

UV light - biosafety cabinet
99% sterilization
Dentis, ORs, ERs, Classrooms (full UV)

Front 34

Mechanical agents:
Air filtration

Back 34

HEPA: high efficiency particulate air
Usually help disinfection only; sometimes sterilization
Air planes
Viruses usually get through

Front 35

Mechanical Agents:
Liquid filtration

Back 35

More likely to be sterilization
No viruses should be in there so sterilize
Helps with heat sensitive media types--sugar solutions
Antibiotics

Front 36

Chemical agents: Gases
Ethylene Oxide

Back 36

Ethylene oxide (ETO) Traditional
Reacts with protein & DNA
Can be used for chemical sterilization
Useful for inanimate/large objects
Useful for large, enclosed chambers
Explosive and carcinogenic

Front 37

Chemical agents: Gases
Propylene oxide

Back 37

Propylene Oxide (safer)
Reacts with protein and DNA
Can be used for chemical sterilization
Less toxic than ETO when broken down
Better for food

Front 38

Chemical agents: Gases
Hydrogen peroxide

Back 38

Oxidizer, causes free radicals that are toxic to bacteria
Can be used for chemical sterilization if high enough concentration
Antiseptic
Sterilize packaged goods

Front 39

Chemical agents: Gases
Chlorine dioxide

Back 39

disrupts proteins
Can be used for chemical sterilization if high enough concentration
Disinfectant
Sterilize equipment & medical waste
Portable
Used to disinfect anthrax

Front 40

Chemical agents: Liquids
Chlorine compounds, halogens

Back 40

Affects cysteine amino acids and disulfide bond of proteins
Can kill bacteria (less effective on endospores & Mycobacteria), fungi, and viruses on inanimate objects if long enough exposure
Disinfect lab counter
Common form of bleach: Sodium Hypochlorite
Chloramine T: antisepsis for wound sand skin
Chlorinate water

Front 41

Chemical agents: Liquids
Iodine compounds, halogens

Back 41

Affects hydrogen and disulfide bonds of proteins
Can kill bacteria (even endospores and Mycobacteria), fungi, & viruses on inanimate objects if long enough exposre
Oldest
Tincture = H2O + I2 + alochol
Iodophors: slow release
Good for burn wounnds, superficial wounds, scrubs
Betadine - antiseptic
Iodine tablets for water

Front 42

Chemical agents: Liquids
Phenolic compounds

Back 42

HARSH/TOXIC
Disrupts cell walls and membranes
Kill most vegetative bacteria, including mycobacteria, fungi and most viruses
Usually in a derivative form
Lysol, disinfectant spray

Front 43

Chemical agents: Liquids
Biphenolic derivatives

Back 43

MILDER
Disrupts cell walls and membranes
Antiseptic and disinfectant, fairly effective on most bacteira, not as effective vs fungi, viruses or endospores or mycobacteria
Triclosan: in antiseptic facewashes
Bactostat: clinical handwash
Microban: built in antimocrobial in inanimate objects
(Concerns: less washing)

Front 44

Chemical agents: Liquids
Chlorhexidine

Back 44

Phenolic rigns with chlorine, also called biguanides
Targets cell membranes and protein structure
Affective on most bacteria (not endospores), not as effective on fungi, viruses, endospores or mycobacteria
Safe on mucus membrane
Exx: Hibicleanse: good full body cleanser/scrub
Endore 400 scrubs
Dentist

Front 45

Chemical agents: Liquids
Hydrogen peroxide

Back 45

Lethal blows of toxic oxygen forms
Effecive vs. bacteria, viruses, fungi, even endospores if enough
Disinfectant of contact lens
Packaging
Antiseptic

Front 46

Chemical agents: Liquids
Alcohol

Back 46

Dehydrates cells and disrupts membranes
Effective on most bacteria (including mycobacteria) & fungi, but not endospores or non-enveloped viruses
70% EtOH so evaporation is slower
Can coagulate protein in deep wounds (bad)
Hand sanitizer
Antibacterial, not antiobitcs

Front 47

Chemical agents: Liquids
Quarternary ammonium or benzylakonium chloride compounds (quats)

Back 47

Polar moleucle that interrups cell membranes
Effecive vs some G+ bacteria, and agaisnt viruses and fungi
Surface disinfectants
Restaurant/Hospital bathrooms
Must be remade
Pseudomonas likes it (biofilm maker)

Front 48

Chemical agents: Liquids
Soaps and enzymes

Back 48

Role in degerming and cleaning only-by breaking up dirt, fats, afluids
No antibacterial component
Removes dirt so microbes cannot adhere

Front 49

Chemical agents: Liquids

Heavy metal compounds

Back 49

Toxic in small amounts = oligodynamic action, binds to protiens and halts metabolism
Effective vs bacteria, fungi, viruses, but not endospores
Cost increases, powerful increases
AgNO3 - infact eyedrops
Silvadene cream
Door handles infused with silver
Mouse silver

Front 50

Chemical agents: Liquids
Aldehydes and Glutaradlehyde

Back 50

Aldehydes like formaldehyde for preservation, too strong for control here
Disrupts enzyme by cross-linking with amino acids
effecftive agisnt pretty much all, one of the few chemical sterilants
Glutaraldehyde: 2% Cidex, used as chemical sterilant in endoscopy eqipment (yellow liquid)

Front 51

Chemical agents: Liquids
Chemical dyes

Back 51

Mechanisms not very clear
Effective against some bacteria and fungi
Crystal violet, malachite green, good for ring worm
Gentian violet
Superficial skin infectiosn: candida albicans, rinworm, athlete's foot.