A bactericide or bacteriocide is a substance that kills bacteria and, preferably, nothing else. Bactericides are either
disinfectants, antiseptics or antibiotics.
Important Functional Groups in a Bactericidal Substance
The most used bactericidal
disinfectants are those applying
chlorine(i.e., hypochlorites, chloramines, dichloroisocyanurateand trichloroisocyanurate, wet chlorine, chlorine dioxideetc.),
oxygen( peroxides, such as peracetic acid, potassium persulfate, sodium perborate, sodium percarbonate and urea perhydrate),
iodine( iodpovidone(povidone-iodine, Betadine), Lugol's solution, iodine tincture, iodinated nonionic surfactants),
alcohols(mainly ethanol, 1-propanol, called also n-propanoland 2-propanol, called isopropanoland mixtures thereof; further, 2-phenoxyethanoland 1- and 2-phenoxypropanols are used),
*phenolic substances (such as
phenol(also called "carbolic acid"), cresols (called "Lysole" in combination with liquid potassium soaps), halogenated (chlorinated, brominated) phenols, such as hexachlorophene, triclosan, trichlorophenol, tribromophenol, pentachlorophenol, Dibromol and salts thereof),
cationic surfactants, such as some quaternary ammonium cations(such as benzalkonium chloride, cetyl trimethylammonium bromideor chloride, didecyldimethylammonium chloride, cetylpyridinium chloride, benzethonium chloride) and others, non-quarternary compounds, such as chlorhexidine, glucoprotamine, octenidinedihydrochloride etc.),
oxidizers, such as ozoneand permanganatesolutions;
heavy metalsand their salts, such as colloidal silver, silver nitrate, mercury chloride, phenylmercury salts, copper sulfate, copper oxide-chlorideetc. Heavy metals and their salts are the most toxic, and environment-hazardous bactericides and therefore, their use is strongly oppressed or canceled; further, also
*properly concentrated strong
acids (phosphoric, nitric, sulfuric, amidosulfuric, toluenesulfonic acids) and
alkalis (sodium, potassium, calcium hydroxides),such as of pH < 1 or > 13, particularly under elevated temperature (above 60°C), kills bacteria.
antiseptics (i.e., germicide agents that can be used on human or animal body, skin, mucoses, wounds and the like), few of the above mentioned disinfectants can be used, under proper conditions (mainly concentration, pH, temperature and toxicity toward man/animal). Among them, important are some
chlorinepreparations (f.e. Daquin's solution, 0.5% sodium or potassium hypochlorite solution, pH-adjusted to pH 7 - 8, or 0.5 - 1% solution of sodium benzenesulfochloramide ( chloramineB)), some
iodinepreparations, such as iodopovidone in various galenics (oinment, solutions, wound plasters), in the past also Lugol's solution,
peroxidesas urea perhydrate solutions and pH-buffered 0.1 - 0.25% peracetic acid solutions,
alcohols with or without antiseptic additives, used mainly for skin antisepsis,
organic acidssuch as sorbic acid, benzoic acid, lactic acidand salicylic acid
phenolic compounds, such as hexachlorophene, triclosanand Dibromol, and
cation-active compounds, such as 0.05 - 0.5% benzalkonium, 0.5 - 4% chlorhexidine, 0.1 - 2% octenidine solutions.Others are generally not applicable as safe antiseptics, either because of their corrosiveor toxicnature.
antibiotics kill bacteria; bacteriostaticantibiotics only slow their growth or reproduction. Penicillinis a bactericide, as are cephalosporins, all belonging to the group of β-lactam antibiotics. They act in a bactericidal manner (by disrupting cell wall precursor leading to lysis).
Aminoglycosidic antibiotics are usually considered bactericidal, although they may be bacteriostatic with some organisms. They act by binding irreversibly to 30s
ribosomalsubunit, reducing translation fidelity leading to inaccurate protein synthesis). The other effect is the inhibition of protein synthesis due to premature separation of the complex between mRNA and ribosomal proteins. The final result is bacterial cell death.
Other bactericidal antibiotics include the
fluoroquinolones, nitrofurans, vancomycin, monobactams, co-trimoxazole, and metronidazole.
List of antibiotics
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