Antiseptics are antimicrobial substances that are applied to living tissue/skin to reduce the possibility of infection, sepsis, or putrefaction. Antiseptics are generally distinguished from antibiotics by the latter's ability to safely destroy bacteria within the body, and from disinfectants, which destroy microorganisms found on non-living objects. Some antiseptics are true germicides, capable of destroying microbes, while others are bacteriostatic and only prevent or inhibit their growth. Antibacterials include antiseptics that have the proven ability to act against bacteria. Microbicides which destroy virus particles are called viricides or antivirals. Antifungals, also known as an antimycotics, are pharmaceutical fungicides used to treat and prevent mycosis.
Surgery
The widespread introduction of antiseptic surgical methods was initiated by the publishing of the paper Antiseptic Principle of the Practice of Surgery in 1867 by Joseph Lister, which was inspired by Louis Pasteur's germ theory of putrefaction. In this paper, Lister advocated the use of carbolic acid as a method of ensuring that any germs present were killed. Some of this work was anticipated by:
Medieval surgeons Hugh of Lucca, Theoderic of Servia, and his pupil Henri de Mondeville were opponents of Galen's opinion that pus was important to healing, which had led ancient and medieval surgeons to let pus remain in wounds. They advocated draining and cleaning the wound edges with wine, dressing the wound after suturing, if necessary and leaving the dressing on for ten days, soaking it in warm wine all the while, before changing it. Their theories were bitterly opposed by Galenist Guy de Chauliac and others trained in the classical tradition.
Alcohols, including ethanol and 2-propanol/isopropanol are sometimes referred to as surgical spirit. They are used to disinfect the skin before injections are given, among other uses.
Hydrogen peroxide is used as a 6% solution to clean and deodorize wounds and ulcers. More commonly, 3% solutions of hydrogen peroxide have been used in household first aid for scrapes, etc. However, the strong oxidization causes scar formation and increases healing time during fetal development.
Iodine is usually used in an alcohol solution or as Lugol's iodine solution as a pre- and postoperative antiseptic. Some studies do not recommend disinfecting minor wounds with iodine because of concern that it may induce scar tissue formation and increase healing time. However, concentrations of 1% iodine or less have not been shown to increase healing time and are not otherwise distinguishable from treatment with saline. Novel iodine antiseptics containing povidone-iodine are far better tolerated, do not negatively affect wound healing, and leave a deposit of active iodine, thereby creating the so-called "remnant", or persistent, effect. The great advantage of iodine antiseptics is their wide scope of antimicrobial activity, killing all principal pathogens and, given enough time, even spores, which are considered to be the most difficult form of microorganisms to be inactivated by disinfectants and antiseptics.
Octenidine dihydrochloride, currently increasingly used in continental Europe, often as a chlorhexidine substitute.
Polyhexanide is an antimicrobial compound suitable for clinical use in critically colonized or infected acute and chronic wounds. The physicochemical action on the bacterial envelope prevents or impedes the development of resistant bacterial strains.
Dakin's solution is a sodium hypochlorite solution, originally also containing boric acid to lower pH. It is mostly used on live tissues for cleaning wounds of bacteria, fungi and viruses. Because of practicality of preparation and lower cost, it is largely used in Veterinary Medicine treatments. It is colourless and does not stain the animal's fur or affect its aesthetic or commercial value.
Super-oxidized solutions contain hypochlorous acid and are stabilised at a neutral pH. SOS are rapidly acting, broad spectrum antiseptics that are clinically effective at non-cytotoxic concentrations that in contrast to many cytotoxic antiseptics, support wound healing. There is now growing consensus that modern SOS are more effective for healing wounds faster.
Evolved resistance
After continued exposure to antibiotics, bacteria may evolve to the point where they are no longer harmed by these compounds. Bacteria can also develop a resistance to antiseptics, but the effect is generally less pronounced. The mechanisms by which bacteria evolve may vary in response to different antiseptics. Low concentrations of an antiseptic may encourage growth of a bacterial strain that is resistant to the antiseptic, where a higher concentration of the antiseptic would simply kill the bacteria. In addition, use of an excessively high concentration of an antiseptic may cause tissue damage or slow the process of wound healing. Consequently, antiseptics are most effective when used at the correct concentration—a high enough concentration to kill harmful bacteria, fungi or viruses, but a low enough concentration to avoid damage to the tissue.
