Microbiology Exam Three

Front 1

sterilization:

Back 1

the destruction or removal of ALL microbes.

Front 2

*suffix*

-static

Back 2

an agent that inhibits growth, but does not kill.

Front 3

*suffix*

-cidal

Back 3

an agent that kills.

Front 4

aseptic:

Back 4

an environment or procedure free from contamination.

Front 5

disinfection:

Back 5

the use of chemical or physical agents to kill or inhibit the growth of microorganisms.

*does not always kill all microbes

Front 6

disinfectant:

Back 6

a chemical that is used on an inanimate object.

Front 7

antiseptic:

Back 7

a chemical that is used on skin and tissue.

Front 8

What are some important things to note about disinfectants/antiseptics?

Back 8

some disinfectants are also antiseptics.

just don't want a chemical to kill tissue, so some can't be.

Front 9

degerming:

Back 9

the removal of microbes from a surface by mechanical means.

Ex. alcohol swab before injections

Front 10

sanitation:

Back 10

disinfection of places or things used by the public.

used to reduce # of pathogens. not the same thing as sterilization.

Front 11

pasteurization:

Back 11

using heat to kill pathogens: used in the food industry.

does not completely sterilize

Front 12

What are the targets of disinfectants and antiseptics?

Back 12

-plasma membrane
-proteins
-cell wall
-nucleic acids

Front 13

surfactants:

Back 13

disrupt the plasma membrane.

made of polar molecules with hydrophobic and hydrophilic regions.

Front 14

heat and strong solvents:

Back 14

break hydrogen bonds.

this denatures proteins.

Front 15

metallic ions:

Back 15

inhibit enzymatic function by blocking the active site

Ex. silver ions

Front 16

radiation:

Back 16

interferes with DNA and RNA function

causes mutations which can permanantly inactivate nucleic acids.

Front 17

which factors affect the rate of microbial death?

Back 17

-number of microbes
-duration of exposure to agent
-temperature
-environment of the microbes
-endospore formation

Front 18

What is clinically relevant about the microbial environment?

Back 18

they are associated with organic material (gross) which inhibits access of the antimicrobial agent.

Front 19

What is important about endospore formation?

Back 19

*may be the most important factor affecting rate of microbial death

these organisms are NOT susceptible to most chemical agents.

Front 20

What are the three major methods for controlling microbial growth?

Back 20

-chemical
-physical (heat/radiation)
-mechanical (filtration/degerming)

Front 21

increase in concentration =

Back 21

an increase in potency

except for alcohol. it needs to have some water in order to denature proteins.

ex. 100% ethanol is LESS effective than 70% ethanol.

Front 22

What are some ways of evaluating antimicrobial chemical agents?

Back 22

-phenol coefficient
-disk method
-use dilution method

Front 23

Who first used phenol as a disinfectant?

Back 23

Joseph Lister

-in 1867-

Front 24

describe the phenol coefficient

Back 24

a way to compare disinfectants

1.0 = same effectiveness as phenol

> 1.0 = greater efficiency

< 1.0 = lesser efficiency

Front 25

describe the disk method

Back 25

tiny disks of filter paper are soaked in the agent and placed on an inoculated agar plate. Inhibition of growth around the disk is called the zone of inhibition.

Front 26

What are some limitations of the disk method?

Back 26

-sizes of the zones are not comparable because they may reflect a difference in concentration and diffusion rate.
-cannot distinguish between microbicidal and microbistatic.

Front 27

What should one consider when selecting an antimicrobial agent?

Back 27

-is it reactive against all organisms without destroying tissue?
-is it effective in the presence of organic material?
-is it stable, and hopefully inexpensive?

Front 28

Chemical agents are...

Back 28

used more frequently than physical means

ineffective against protozoan cysts and bacterial endospores.

Front 29

What are eight major categories of chemical agents?

Back 29

-phenol and phenolic compounds
-alcohols
-halogens
-oxidizing agents
-surfactants
-heavy metals
-aldehydes
-gaseous agents

Front 30

Phenol and phenolic compounds.

-use/properties?-

Back 30

-effective in presence of organic material
-commonly used as disinfectants in hospitals.

Front 31

phenol and phenolic compounds

-examples?-

Back 31

-Lysol
-triclosan

Front 32

alcohols

-use/properties?-

Back 32

-disinfectant AND antiseptic
-used as degerming agent before injections

Front 33

alcohols

-examples?-

Back 33

-isopropanol (rubbing alcohol)
-ehanol

Front 34

halogens

-use/properties?-

Back 34

some are disinfectants and some are antiseptics

Front 35

halogens

-examples?-

Back 35

-iodine- one of the oldest antiseptics
-tincture (iodine + alcohol)
-iodophore (iodine + organic) it is slow releasing and less irritating.

-chlorine- swimming pools/ bleach

Front 36

oxidizing agents

-examples?-

Back 36

-hydrogen peroxide: household antiseptic (not very effective)

-ozone: hot tubs/ water supply

Front 37

surfactants

-use/properties?-

Back 37

-soap: good degerming, but not so good antimicrobial

-detergent: may have antimicrobial, more soluble, no soap scum

*soap makes water wetter*

Front 38

surfactants

-examples?-

Back 38

-QUATS: quaternary ammonium compounds

pseudomonas can still grow in this! eek

Front 39

heavy metals

-use/properties?-

Back 39

used to be used in eyes of newborns to prevent gonorrhea

still used in surgical dressings and burn creams

bacteriostatic

Front 40

heavy metals

-examples?-

Back 40

silver nitrate

Front 41

gaseous agents

-use/properties?-

Back 41

for things that are sensitive to heat or chemicals

explosive, poisonous

Front 42

gaseous agents

-examples?-

Back 42

ethyline oxide
(dentists use it)

Front 43

aldehydes

-use/properties?-

Back 43

disinfectants NOT antiseptics

innactivate proteins and nucleic acids
irritate mucous membranes

Front 44

aldehydes

-examples?-

Back 44

-formaldehyde: used to disinfect isolation rooms/surg. equipment /dialysis machine

-glutaraldehyde

Front 45

What are the two ways to use heat for killing microbes?

Back 45

Dry heat: oven/flame/incinerator - for glass or powders

moist heat: more penetrating - boiling won't kill endospores

Front 46

What are the three ways of using moist heat?

Back 46

-boiling
-pressurized steam (autoclave) kills endospores
-paseurization

Front 47

How does an autoclave work?

Back 47

pressurized steam: it can be heated higher than boiling water

don't put things that are sensitive to heat or moisture in autoclave.

Front 48

How does an autoclave kill endospores?

Back 48

it heats up to 121 degrees and 15 pounds per square inch. endospores die within 15 minutes.

Front 49

What are some other methods of controlling microbial growth?

Back 49

-filtration
-radiation
-non-ionizing radiation (UV light)

Front 50

What is filtration used for?

Back 50

to sterilize air or liquids

Front 51

How is non-ionizing radiation used?

Back 51

germicidal lamps

surfaces only

damages skin and eyes

Front 52

Why is ionizing radiation safe?

Back 52

the radioactive substance does not actually touch the foods. they do not become radioactive. that's just silly.

Front 53

Why are antibiotics important?

Back 53

they have drastically reduced the number of deaths due to infection.

Front 54

How many antibiotic prescriptions are written in america each year?

Back 54

an estimated 80 million

Front 55

how much antibiotic is produced each year?

Back 55

12500 tons

with 25-50% being fed to livestock to increase weight gain.