ACTION AND USE. This is used in a 70 percent solution as a skin antiseptic; it is volatile and also has a desiccating (drying) effect on the skin.
ACTION AND USE. A synthetic preparation, hexachlorophene is a bacteriostatic cleansing agent most effective against gram positive organisms. Pus or serum decrease the efficacy. Hexachlorophene is a neurotoxic agent and must not be used on premature infants, denuded skin, burns, or mucous membranes. It is used as an antiseptic scrub by physicians, dentists, food handlers, and others. Residual amounts can be removed by alcohol.
ACTION AND USE. The soluble salts of silver ionize in water to produce solutions that are astringent and antiseptic in high concentration. In solid form, silver nitrate is most commonly used to cauterize mucous membranes or treat aphthous ulcers. The most common side effect is the skin turns black where the silver nitrate has come into contact with it. This black area is slow to absorb but is not harmful. In liquid form, it is used to prevent gonorrhea ophthalmia in the newborn (eye drops) or as a wet dressing on burns. Caution must be taken to keep the dressing wet; silver will precipitate from a drying dressing and can be absorbed through the skin. The effect is a condition known as agyria, where the skin turns a slate gray. There is no known reversal for this condition.
ACTION AND USE. A somewhat effective, non-injurious surface disinfectant, benzalkonium chloride is germicidal for a number of grampositive and gram-negative organisms including some fungi. It is inactivated by soap or alcohol, and is not effective against spores or viral pathogens. It is most commonly used as a cleansing agent in animal bites.
ACTION AND USE. Glutaraldehyde is effective against vegetative gram-positive, gram-negative, and acid-fast bacteria, bacterial spores, some fungi, and viruses. It is used in an aqueous solution for sterilization of fiber optics, plastics, rubber, and other materials that are not resistant to heat.
ACTION AND USE. An organic mercury compound, thimersol is non-irritating to the skin and mucus membranes when applied topically. It has antiseptic, germicidal, and fungicidal properties.
ACTION AND USE. Certain oxidizing agents are destructive to pathogenic organisms but mild enough to be used on living tissue. Hydrogen peroxide is a germicide that is active by the release of oxygen. It deteriorates on standing to oxygen and water. It is most commonly used to clean suppurating wounds, and is also efficious in the treatment of Vincents angina (trench mouth). For external use only, it is available as a 3 percent solution.
Antibiotics are chemical compounds produced as the result of metabolic activity of microorganisms or produced synthetically. They inhibit the growth of susceptible microorganisms or kill them through the destruction of necessary enzymes. Antibiotics that are sufficiently non-toxic to the host are used as chemotherapeutic agents in the treatment of infectious diseases of man, animals, and plants. They can be administered orally, topically, or parenterally.
The five basic mechanisms of action for the antimicrobial agents are (1) inhibition of the synthesis of the bacterial cell wall, (2) affecting the cell wall permeability, (3) inhibition of protein synthesis by affecting ribosomal activity, (4) affecting nucleic acid metabolism, and (5) the antimetabolites that compete with necessary enzymes. To be of practical value in the treatment of infection, an antimicrobial agent must exert it effects upon the invading microorganism without seriously damaging the cells of the host. The following are groups of antimicrobial agents and their general mechanisms of action.