Chapter 7 Microbial Control Chemical Methods

Microbial Control Chapter 7

Chemical Methods
Fall into two categories:
Antiseptics: reduce the number of microbes and viruses on living tissue
Disinfectants: destruction of most microorganisms and viruses on non-living tissue

I Alcohol
A. Isopropanol (rubbing alcohol) 70%
B. Ethanol 90% alcohol
C. denatures proteins and disrupt cell membranes
D. Kills most microbes (not spores)
E. Used as antiseptic or disinfectant
II Chlorine: denatures proteins
A. Hypochlorite (Bleach)
B. Chloramine (Cl & NH3)
C. Gas
D. Widely used as disinfectant, antiseptic, and water purification
III Phenols: denatures proteins and disrupts cell membranes
A. Examples: Lysol, hibiclens, phisohex, triclosan
B. Widely used as skin antiseptic and disinfectant, but harsh on skin
IV Iodine: denatures proteins
A. tincture (mixed with alcohol)
B. iodophors (betadine)
C. widely used as a skin antiseptic
V QUATS (quanternary ammonium compound): disrupt cell membranes
A. surface active chemicals (surfactants)
B. detergents: zepharin & cepacol
C. Antiseptic: mill many microbes, but spores and others are resistant.
D. works effectively against gram + bacteria
VI Hydrogen Peroxide: denatures proteins
A. used as antiseptic or disinfectant for deep wounds
B. a catalyst enzyme (by product of aerobic respiration….oxidation)
VII Formaldehyde & Gluteraldehyde: denatures proteins and inactivating nucleic acids
A. kills all microbes and spores
B. toxic and irritating
C. used as preservative and for vaccine production
VIII Ethylene Oxide: denatures proteins
A. gas
B. kills all microbes and spores
C. Sterilization of heat and water-sensitive objects
D. widely used on medical supplies and equipment
E. may be carcinogenic