antiseptic (redirected from antibacterial)

antiseptic, agent that kills or inhibits the growth of microorganisms on the external surfaces of the body. Antiseptics should generally be distinguished from drugs such as antibiotics that destroy microorganisms internally, and from disinfectants, which destroy microorganisms found on nonliving objects. Germicides include only those antiseptics that kill microorganisms. Some common antiseptics are alcohol, iodine, hydrogen peroxide, and boric acid. There is great variation in the ability of antiseptics to destroy microorganisms and in their effect on living tissue. For example, mercuric chloride is a powerful antiseptic, but it irritates delicate tissue. In contrast, silver nitrate kills fewer germs but can be used on the delicate tissues of the eyes and throat. There is also a great difference in the time required for different antiseptics to work. Iodine, one of the fastest-working antiseptics, kills bacteria within 30 sec. Other antiseptics have slower, more residual action. Since so much variability exists, systems have been devised for measuring the action of an antiseptic against certain standards. The bacteriostatic action of an antiseptic compared to that of phenol (under the same conditions and against the same microorganism) is known as its phenol coefficient. Joseph Lister was the first to employ the antiseptic phenol, or carbolic acid, in surgery, following the discovery by Louis Pasteur that microorganisms are the cause of infections. Modern surgical techniques for avoiding infection are founded on asepsis, the absence of pathogenic organisms. Sterilization is the chief means of achieving asepsis.

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antiseptic

Any of a variety of agents applied to living tissue to destroy or inhibit growth of infectious microorganisms. An antiseptic's efficiency depends on concentration, time, and temperature. It is most valuable in the disinfection of contaminated wounds or skin surfaces when a wide margin exists between the concentration at which it is germicidal and that at which it is toxic to the body's cells. Many antiseptics destroy specific types or forms of microorganisms (e.g., bacteria but not spores). Among the major families of antiseptics are alcohols, phenols, chlorine and iodine compounds, mercury-based tinctures, certain acridine dyes, and some essential oils. Antiseptics are distinguished from disinfectants, which are germicidal agents used to destroy microorganisms on inanimate surfaces. See also antibiotic.