unit 6 (2/3) - chemical methods

describe the application of the following AMAs

1. antiseptics

2. disinfectants

3. antibiotics

1. disinfects living tissue - skin, mucous membranes

2. controlled removal of vegetative pathogens on surfaces, inanimate objects

3. treat infectious diseases in living organisms

8 categories of chemical antiseptics and disinfectants

PHHASAGO

PLEASE HELP HARRY AND SALLY [AVOID GETTING OVERWHELMED]

1. phenols

2. heavy metals

3. halogens

4. alcohols

5. surfactants

6. alkylating agents

7. gaseous alkylating agents

8. oxidizing agents

phenols, phenolics

• how it works as chemical method

• where it was first used, and for what purpose

• disrupts lipids in plasma membranes, and denatures enzymes

• was first used by joseph lister to reduce post-surgical infections (germ theory)

phenol derivatives (2) and their purposes

bisphenols, phenolics - to reduce irritation and increase microbial action

chemical method effective against bacteria and yeast

phenols, phenolics

heavy metals

• how it works as a chemical method

• 3 examples of heavy metals

• high molecular weight of metals denature proteins

TYPES

• silver

• copper

• zinc

examples of how silver is used as chemical agent

antiseptic in eye drops, silver-impregnated products

examples of how copper is used as chemical agent

algicide in swimming pools

fungicide in paint

examples of how zinc is used as chemical agent

mouthwashes, anti-dandruff shampoos

halogens as a chemical method

• how it works

• 2 types of halogens

• oxidizes proteins and cell membranes

TYPES

• iodophors

• chlorine

iodophors - what it is effective against

halogen type - effective against endospores, bacteria

chlorine - what it is effective against

halogen type effective against most microorganisms

alcohols

• how it works as chemical method

• what it is effective against

• works by protein denaturation, membrane disruption

• effective against bacteria, fungi, enveloped viruses

concentration % alcohols work best at

70-90%

what chemical method can induce endospore formation

alcohols can induce endospore formation

examples of 2 alcohols : “drinking” and “rubbing” alcohol

• isopropanol (rubbing alc)

• ethanol (drinking alc)

surfactants

• definition

• 2 types

• chemical compound lowering surface tension btwn 2 things (liquid - liquid, gas-liquid, liquid - solid)

TYPES

• soaps and detergents

• quaternary ammonium compounds

soaps and detergents

• describe path of action

• decrease surface tension of water, so fats can be emulsified into small drops to remove microbes in the emulsified oily film(degerm)

QUATs

• chemical compound

• effect it has on microbes

• how do quats work?

quaternary ammonium compounds (NH4+)

• cationic detergents ex/ cetylpryridinium chloride

• denatures proteins and disrupts plasma membranes

• can insert themselves into the bacterial phospholipid bilayer

effectiveness of QUATs on gram-positive VS gram-negative bacteria

(+): QUATs is effective

(-): pseudomonas bacterium will thrive in QUATs

alkalating agents

• how it is effective against microbes

• how do these agents work

• denatures proteins and damages DNA

• work by replacing a hydrogen atom in a mlc with an alkyl group; inactivates the nucleic acids and enzymes

3 examples of alkylating agents

glutaraldehyde

formaldehyde

ethylene oxide and propylene oxide

gaseous alkylating agent

• what it kills

• what it is used for

• kills endospores and all microbes (sterilizing)

• used to sterilize equipment at room temp

oxidizing agent

• effect it has against microbes

• 2 examples of oxidizing agent

• oxidizes microbes’ proteins and cell membranes

  • hydrogen peroxide

  • ozone (O3)

effective chemicals that can destroy endospores

• ethylene oxide gas

• aldehydes

• high concentration halogens, oxidizers

we usually have to rely on [chemical / physical] methods to destroy endospores

[physical]