•Disinfectants – treat non-living material
•Antiseptics – treat the surface of a living
organism
•Chemotherapeutic agents – used within a
living organism; an example is antibiotics
Classes of Antiseptics and Disinfectants 1
Alcohols
• Straight chain – ethyl and isopropyl. Both are
most effective at about 70% concentration
• Phenols (carbon ring); Lysol, hexachlorophene
Classes of Antiseptics and Disinfectants 2
Heavy Metals
• Mercury compounds; mercurochrome
• Silver compounds; silver nitrate used in
newborn’s eyes to prevent possible gonorrhea
infection
Classes of Antiseptics and Disinfectants 3
Halogens
• Chlorine compounds: bleach (Chlorox) used as
disinfectant; also used to clean drinking water
• Iodine compounds:
– Tincture of iodine used as antiseptic
– Betadine used as a disinfectant or as an antiseptic,
kills spores, used to pretreat an area in which an
incision will be made
Classes of Antiseptics and Disinfectants 4
Soaps and Detergents
• Relatively weak toxic effect, but effectively
removes microbes from surfaces
• May disrupt cell membranes
Classes of Antiseptics and Disinfectants 5
Peroxides
• Hydrogen peroxide is a toxic oxygen product.
Has been used on the skin and as a
mouthwash.
Mode of action of Disinfectants
• Most denature proteins
• Some produce toxic oxygen products, in an
oxidative burst: bleach and hydrogen
peroxide.
• Spores are most resistant to chemical agents
• Mycobacteria are relatively resistant, due to waxy
wall, which prevents penetration
• The outer membrane of Gram - bacteria provides a
barrier to penetration of some chemicals, so these
are more resistant than Gram +
• Pseudomonas (Gram -) is especially resistant
because it can use many uncommon carbon
sources for growth, including some antiseptics