MECHANISMS OF ACTION OF DISINFECTANTS

Disinfectants and biocides are a chemically diverse group of agents wh ich are generally considered to exhibit poor selective toxicity. This should not be mistaken for poor target specificity, however, and much is now known concerning the damaging interactions which may arise betw een bacterial cell and disinfectant agent. Critical governing features of these interactions are the physicochemical characteristics of the chemical agent, cell morphology, and the physiological status of the m icroorganism. Antibacterial events include membrane disruption, macrom olecule dysfunction, and metabolic inhibition; the consequential effec t is determined by the relative contribution(s) of the target(s) to mi crobial cell survival and the possible initiation of self-destructive processes. Disinfection kinetics offer a measure to differentiate betw een physiochemical and chemical interactions. Increasingly demanding d isinfectant applications require more sophisticated use of biocidal sy stems. Approaches include: agents in combination, whereby a knowledge of mechanism of action assists in designing optimal mixtures; intracel lular biocide delivery, using cellular transport processes to overcome cellular barriers; and targeted donation of biocide from delivery sys tems, requiring an understanding of target reactivity. A knowledge of disinfection mechanisms provides a basis from which novel chemistries and synergistic combinations may be developed. (C) 1998 Elsevier Scien ce Ltd. All rights reserved.