Overview Perspective of Bacterial Strategies of Resistance to Biocides and Antibiotics

Considerable controversy surrounds the use of biocides in an ever-growing range of consumer products and the eventuality that their indiscriminate consumption might decrease biocide effectiveness and modify susceptibilities to antibiotics. Several line of evidence suggest that exposure to biocides may cause increased antibiotic resistance. Thus, we reviewed the common resistance strategies of bacteria against both biocides and antibiotics. Several publications have explained the cell target of biocides and the various mechanisms used by bacterial cells to escape biocides’ toxic activity. Here, we briefly reviewed the commonly used resistance mechanisms of bacteria against both biocides and antibiotics. Biocides could act on multiple sites in microorganisms and cause resistance by non-specific means. We mentioned several mechanisms such as efflux pumps, cell wall changes to the reduction of permeability, genetic linkage with both biocide resistance genes and antibiotic resistance genes, the penetration/uptake changes in envelope by passive diffusion, effect on the integrity and morphology of membrane, and effects on diverse key steps of bacterial metabolism. Along with this toxic effect and stress, bacterial cells express some similar defense strategies that can overlap the main functions conferring resistance versus structurally non-related molecules. It can be stated that healthcare-associated, community-acquired, and nosocomial infections should be surveyed annually. Since biocide-antibiotic cross-resistance can be conferred by a number of distinct mechanisms, it is important to evaluate the propensity of a bacterium to express these mechanisms. Advances in modern genetic methods and the development of an assay using specific chemosensitizers or markers might allow the development of routine tests to identify resistance mechanisms. Further studies are needed to establish a correlation between biocide exposure (s) and development of antibiotic resistance, but the number of studies in the clinical or environmental settings is limited.