Chapter 5: Control of Microbial Growth - Chemicals (Alcohols, Metals, QUATS, etc.) Flashcards
How does alcohol work? (2)
- denatures proteins and disrupts membranes
- acts quickly and evamporates
What microbes does alcohol kill? What does it not kill? (2 and 2
- bacteria and fungi
- does not kill endospores and some viruses
Where is alcohol used on? (2)
- surfaces in a lab
- degerm skin
Is alcohol an adequate antiseptic? Why or Why not? (2)
- no
- often combined with other chemicals to increase effectiveness
- citric acid or urea, isopropyl
What are 2 types of alcohol?
- ethanol - 70% most effective
- isopropanol rubbing alcohol
Why are heavy metals used on microbes?
- copper, silver, zinc and mercury can inhibit microbes
How does SILVER NITRATE (1%) affect microbes? In other words, when is it used? (1)
- used as eyedrops for new-born infants to protect agents gonorrheal opthalmia
When is silver sulfadiazine used?
- in topical creams for burns
Why are silver ions used in some bandages and catheters?
- it slows the growth of microbes
When is copper sulfate used to control microbes?
- inhibits algae in reservoirs
When is mercuric chloride used to control microbes?
- used in paint to control mildew
very toxic cuz it has mercury
When is zinc chloride used to control microbes?
- used as an antiseptic in mouthwashes
Are soap and detergents disinfectants or antiseptics?
- neither
- works to degerm skin
Why is soap and detergent important?
- important in mechanical removal of microbes
How do soaps/detergents work? (2)
- soap breaks up oily deposits and film (ex. on skin)
- water can then wash these deposits away, along with microbes
What are quaternary ammonium compounds (quats)? (2)
- cationic detergents
- strongly antimicrobial colorless, tasteless, odorless, and non-toxic at low concentrations
What microbes do quats kill/not kill? (3)
- kills most bacteria, fungi, and some viruses
- does not kill endospores
- does not kill some gram - bacteria
Give an example of a quat, and what it is used for.
- cepacol
- used as a mouthwash
Some gram negative bacteria not only survive, but grow well on Quats. Give an example of one, and include what infection it causes
- Pseudomonas aeruginosa
- cause of burn infections
What are gaseous chemosterilizers?
- chemical gasses used for sterilization
What chemical is a gaseous chemosterilizer?
- Ethylene oxide
How does ethylene oxide work? (2)
- denatures proteins
- germicidal
- requires 4-18 hours of exposure
What microbes does ethylene oxide kill?
- ALL of them
- including endospores and viruses
Can ethylene oxide pass through plastics?
- yes, it is highly penetrating
What is ethylene oxide used to sterilize?
- disposable hospital equipment and lab suppies
- ex. plastic tubing
- disposable swabs
How do oxidizing agents work?
- oxidizes and denatures proteins
Oxidizing agents are useful against ____ organisms
anaerobic organisms
in lecture, its bc these organisms lack enzymes to survive
Name 3 common oxidizing agents
- hydrogen peroxide
- ozone
- benzoyl peroxide
What is hydrogen peroxide used on?
- common antiseptic for wounds
What is ozone used for?
- used with chlorine to disinfect water
What is benzoyl peroxide used for? (2)
- used as an antiseptic on skin
- kills anaerobic bacteria living in tissues
ex. Bacteria that causes acne
