Fact and Fantasy Regarding Resistance to Microbicides

Resistance to animal and human therapeutic antibiotics is well known and understood among both the scientific and lay community. Performance failures with industrial microbicides are commonly discussed as if the same phenomenon occurs here also. Much of this is indeed fantasy, as the mode of action of most, but not all, industrial microbicides are based on a fundamentally different principle than are therapeutic antibiotics. Industrial microbicides are designed to be broad spectrum and achieve this by attacking some fundamental principle that is present in most microorganisms and without which the organism cannot survive. Antibiotics, on the other hand, are designed to be as narrow spectrum as possible, so that side effects in the animal or human host are minimized. A clear understanding of why a broad spectrum microbicide fails in a particular situation is necessary in order to have a successful program. Application errors, such as using an inappropriate biocide and calling it resistance, will ultimately be economically detrimental. Using different modes of action products in sequence is understood in antibiotic science to encourage true resistance. This may very well also promote resistance in broad spectrum microbicides. A thorough understanding of microbicides and the particular industrial situation in which they are used is necessary to have a successful, cost-effective program, while minimizing promotion of resistance.