Disinfectants have an Thus, it has been suggested that activation of efflux pumps by biocides enhances antibiotic resistance in bacteria (30, 33). More recently, the choice has become more challenging with the introduction of new disinfectants (e.g. improved hydrogen peroxide, peracetic acid/hydrogen peroxide) and disinfection technologies (e.g. Quaternary ammonium compounds are another class of disinfectant that will attack the lipid structure of the viral envelope, and these are typically used as surface disinfectants. The ecological dynamics of microbial communities where QACs are a main line of defense against exposure to pathogens need to be better understood in terms of sublethal doses and antibiotic resistance. QACs are membrane-active agents interacting with the cytoplasmic membrane of bacteria and lipids of viruses. QAC chemistry is a continually evolving area, with new product formulations appearing in the market to meet challenges posed by emerging pathogens. Better standardized tests for assessing and defining the differences between increases in tolerance versus resistance are needed. 1.1 This test method covers a potentiometric titration procedure for determining active matter in disinfectant quaternary ammonium salts. Research has shown quaternary ammonium compounds to effectively kill most bacteria, viruses, and fungi. Author information: (1)Nofima, The Norwegian Institute of Food, Fishery and Aquaculture Research, N-1430 Aas, Norway. The basic QAC structure is show in Fig. QACs also interact with intracellular targets and bind to DNA (4). He was a faculty member in the Department of Virology and Epidemiology at the Baylor College of Medicine from 1974 to 1981. Disinfectants play an important role in maintaining acceptable health standards by significantly reducing microbial loads as well as reducing, if not eliminating, pathogens. Rass Clin Ter. Since efflux pumps are believe to account for at least some of the increased tolerance found in bacteria, there has been concern that this will enhance the resistance of bacteria to certain antibiotics. During an outbreak of norovirus in a school, a QAC was found not to have stopped virus transmission, but a nonregistered product for norovirus had been used (18). Cleaning products that contain QACs and other disinfectants are commonly used in homes, work-places, and public spaces. Numerous studies on the efficacy of disinfectants against this virus have been conducted (Table 3); mouse norovirus and feline calicivirus are the most commonly used surrogates. The fresh quaternary ammonium and binary compound achieved a greater kill (P