bactericide

A bactericide is an antiseptic or disinfectant designed to kill bacteria. It is distinguished from a bacteriostatic agent, which only inhibits bacterial growth, and from sporicides, which kill bacterial spores. A substance may be bactericidal for vegetative bacteria without being sporicidal.

Mechanisms of action vary and include disruption of cell membranes, denaturation of proteins, and damage to nucleic acids or metabolic pathways. Alcohols and quaternary ammonium compounds often disrupt membranes; oxidizing agents such as chlorine compounds, hydrogen peroxide, and peracetic acid damage cellular components; phenolics and biguanides affect membranes and proteins.

Common bactericides include ethanol and isopropanol; chlorine-based disinfectants (for example, sodium hypochlorite); hydrogen peroxide; peracetic acid; quaternary ammonium compounds; iodine-based solutions; and chlorhexidine. The choice of agent depends on the context, including the type of surface or material, required contact time, and whether sporicidal activity is needed.

Applications span healthcare, laboratories, food processing, and water treatment, where bactericides help reduce microbial contamination. In clinical and consumer products, claims of bactericidal activity are typically supported by standardized efficacy testing and regulatory approval or registration, which vary by country or region.

Safety and environmental considerations are important. Proper dilution, contact time, and substrate compatibility affect effectiveness and safety. Overuse or misuse can contribute to irritation, material damage, and, in some cases, development of resistant bacteria or disruption of beneficial microbiota.