Chapter 7 - chemical methods of microbial control

anionic soaps and detergents

(ex of a surfactant) usually contain sulfates or phosphates and are general degermers

hexaxclorophene

(example of a phenol-related compound - Bisphenol)somewhat toxic; used in clinical soaps/skin cleansers

Triclosan

(example of a phenol-related compound- Bisphenol) widely used (overused?) in commercial "antibacterial" soaps

copper sulfate

(from copper) used to kill algae in water tanks and pools

silver iodide (surfacine)

(from silver) more recently used in some burn ointments, which when applied to surfaces, continues to have antimicrobial activity even after several days

silver sulfadiazine

(from silver) used in some burn ointments in the past

silver nitrate

(from silver) used in the past to prevent gonorrheal opthalmia neonatorum in newborns

zinc chloride

(from zinc) used in mouthwashes and toothpastes

zinc oxide

(from zinc) used in some paints to inhibit fungal growth

ethanol or isopropanol

good for degerming skin and other surfaces, but its rapid evaporation makes it less effective as an antiseptic/disinfectant

Glutaraldehyde

(an aldehyde) not as disagreeable as formaldehyde; used to sterilize some types of medical equipment

formaldehyde (formalin is a 37% solution in water)

(an aldehyde) the traditional embalming agent used less and less because of its toxicity, irritability and odor

Biphenols

2 phenol rings joined by a "bis" bridge: antiseptic

chlorine gas (in water) and an example

C12 + H20 ------> H+ - Cl- +H0Cl (hypochlorous acid) ex: chlorinating drinking water and swimming pools

supercritical CO2

CO2 compressed to a supercritical state; used to sterilize organic implants.

Heavy metals

Denature proteins by oligodynamic action

Oxidizing agents

Destroy biomolecules in general

Phenol-related compounds

Disrupt cell membranes

Alcohols control microbe by___ and are used as___

Disrupt cell membranes/denature proteins; used as antiseptics/disinfectants

Organic acids

Generally used as anti-fungal preservatives

example of phenolics

O-phenlyphenol (LysoIR) - very stable

Chemical methods of microbial control include:

Phenol-related compounds, halogens, alcohols, heavy metals, oxidizing agents, surfactants, organic acids, aldehydes, gaseous sterilizers, plasma gas sterilizer

Aldehydes

Powerful protein denaturants; sterilize after 10-12 hours exposure

chlorine is used

as a general disinfectant

sodium nitrate

although not an organic acid, it's used as a preservative in processed "meats" to inhibit growth of Clostridium botulinum (bacteria that grows on food) and to inhibit endospore germination. A red dye is added to the sodium nitrate, which gives the color to boloney and hot dogs

mercurochrome

antiseptic (from mercury); used on small cuts

phenol (or "carbolic acid") was first use as____ by ____

antiseptic/disinfectant by Joseph Lister

two examples of quaternary ammonium compounds (cationic detergents - surfactants)

benzalkonium chloride (BactineR) and cetylpyridnium chloride (ScopeR)

biguanides example

chlorhexidine

Surfactants

decrease surface tension of liquids making it possible for water and oils to mix (they help remove dirt, oil, and grease

Halogens

denature proteins

phenolics are

derived by phenol; used in disinfecting cleaning agents

two examples of gaseous sterilizers

ethylene oxide and propylene oxide

cationic detergents

example of a surfactant

iodophors (ex: betadine)

iodine + organic molecule; used broadly to disinfect skin

tincture of iodine

iodine in an alcohol solution; used on small cuts

hypochlorite and an example

multipurpose disinfectant; choroxR bleach: "sodium hypochlorite"

sorbic and benzoic acids/salts

organic acids used in acidic foods like cheeses and soda

methyl and propyl parabens

organic acids used in personal care products and cosmetics

peroxides type of

oxidizing agent to destroy biomolecules

Gaseous sterilizers

powerful protein denaturants; sterilize after 4 hour exposure; used to sterilize medical equipment (especially electronic devices and materials that cannot be sterilized in any other manner)

peracetic acid

sterilizes after 30 min exposure; used to sterilize medical food processing equipment

quaternary ammonium compunds ("quats")

surfactant that disrupts cell membranes; are found in both antiseptics and disinfectants and have good dergerming foaming action

phenol

the old standard for antiseptics/ disinfectants; too irritating to be used today

benzoyl peroxide

used as a antiseptic agent in acne medications

biguanides are used as

used as antiseptic in clinical soaps and skin cleansers

iodine

used in antiseptics

hydrogen peroxide

used to disinfect inanimate objects, such as food packaging, and as a non-chlorine "bleach". Also used as an antiseptic (topical and oral, but catalase reduces its effectiveness) and as a sterilizer

ozone gas

used to disinfect water supplies (along with chlorine)

plasma gas sterilizer

uses hydrogen peroxide gas illuminated by microwaves, which results in highly destructive "free radicals" that destroy biomolecules and sterilize after 1-2 hours exposure; used mostly to sterilize medical equipment