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