Does microbial resistance or adaptation to biocides create a hazard in infection prevention and control?

Increased numbers of healthcare-acquired infections, including those caused by antibiotic-resistant microbes, have created a need for improved infection control use of disinfection regimens. Commensurate with this has been an increasing number of reports on resistance to a wide variety of antimicrobials, including biocides. Cross-resistance between these biocides and other biocidal or antimicrobial agents has been well-documented. Much of the literature lacks clear distinctions between adaptation of organisms to exposure to biocides, which reverses upon removal of the biocide, as opposed to resistance. Depending on the genetic basis of this resistance, it may be high level and not readily reversible. This lack of clear definitions complicates the evaluation of the relevance of these phenomena in practice. In this review we propose definitions of adaptative processes and biocide resistance and survey the literature according to these definitions. We conclude that the current risks to healthcare delivery caused by resistance related to biocides are low, provided that biocides are used under appropriate conditions. The need for further research is addressed.