S21: Rethinking the use of Disinfectants and Microbial Resistance

Various types of chemical and physical biocidal processes are widely used for public health and industrial applications, to include antisepsis, disinfection, preservation and sterilization.  They play a significant role in protecting against the transfer to microorganisms that can cause disease, contamination and product spoilage.  Despite their widespread use, few studies investigate their mechanisms of action and/or the risks associated with resistance of the various types of microorganisms to their antimicrobial effects.  In contrast, the development of resistance to anti-infective drugs (in particular antibiotics) has been well described and is a significant healthcare concern.  Microorganisms, depending on structure, have been traditionally classified as presenting an expected hierarchy of resistance to biocides, ranging from the relatively sensitive enveloped viruses to the highly resistant bacterial spores.    Such intrinsic resistance profiles have where defined over 50 years and are and are rarely challenged. However, our knowledge of microbiology has grown significantly over the last 50 years and expected endpoints of preservation, disinfection and sterilization should be reconsidered.  Depending on the biocidal process under investigation and its potential application, the intrinsic resistance of microorganisms can vary considerably.  Microorganisms have been recently described to present some unusual mechanisms of resistance that may be significant in some applications. In addition to the known intrinsic resistance of microorganisms, acquired resistance mechanisms have also been described, due to mutations or genetic material acquisitions.  In the past these reports have rarely been published as being significant (leading to failure of the antimicrobial process).  In some recent cases, acquired mechanisms of resistance challenge our current understanding of the ability of these products to be effective for their intended use.  This presentation will review some of the more recent and significant reports of biocide resistance, with emphasis on the industrial and clinical implications of these reports.