Evaluación de la resistencia a agentes desinfectantes de bacterias aisladas de ambientes naturales

antiseptics and disinfectants are widely used for prevention, surveillance and control of infections. among those most used are quaternary ammonium cationic compounds (qacs). the daily use and abuse of these compounds has resulted in the selection of resistant bacterial strains. in this study we decided to evaluate the resistance to disinfectant agents of bacterial strains multiresistant to frequently used antibiotics, both isolated from natural environments and isolated from hospital patients. the quantitative suspension test was used to evaluate resistance levels, and bacterial conjugation assays to examine the possible association of resistance determinants to transferable plasmid molecules. gram negative microorganisms such as pseudomonas aeruginosa appeared to be the most resistant. environmental strains showed higher resistance levels as compared with hospital strains. we obtained transconjugants with resistance levels similar to those of the respective donor strain, indicating that these determinants of resistance to disinfectants are coded in plasmids; when analyzed by restriction patterns they showed that there were at least two plasmid molecules disseminated among the strains of the same habitat. our results represent a contribution that will allow to implement more successful measures to avoid the dissemination of these resistant bacteria