Selected Article


Antibiotic resistance by biocide exposure


Antibioticresistance is one of the great global challenges in modern medicine. Antibioticresistance can occur as a result of resistance mutations or via horizontal genetransfer. Biocides are crucial to successful infection control and widely usedin hospitals, on farms, in industry and in the home for the control ofmicroorganisms. Exposure of bacteria to biocides can select for mutants withdecreased biocide susceptibility and these mutants often display a decrease insusceptibility to various antibiotics, indicating that biocides can act asdrivers of antibiotic resistance under laboratory conditions. Many commonbiocides are not detectable in the environment and some, such as triclosan,have been found in human urine, serum and breast milk. The accumulation ofbiocides in the environment also represents a potentially prolonged andlow-level stress that causes decreased biocide susceptibility, which could becross-resistant to antibiotics. Mark A.Webber et al found Salmonella entericaserovar typhimurium mutants highly resistant to both quinolone antibiotics andthe biocide triclosan. Rebecca Wesgate et al showed that exposure to triclosan(0.0004%) was associated with a high risk of developing resistance andcross-resistance in Staphylococcus aureus and Escherichia coli. Lu Lv et al Theemerging halogenated nitrogenous disinfection products could raise antibioticresistance, even multidrug resistance, in P. aeruginosa PAO1 via mutagenesis,which was demonstrated by mutation detection. C. soumet et al investigatedadaptive responses of bacterial strains by exposing the strains daily toincreasing sub-inhibitory concentrations of DDAC(didecyl dimethyl ammoniumchloride) for 7 days. Following adaptation to DDAC, reduced susceptibility wasfound in Escherichia coli, Listeria monocytogenes and Salmonella strains to BC(benzalkonium chloride) and a commercial biocide formulation (Galox Horizon)containing DDAC and glutaraldehyde. Keywords:antibioticresistance, biocide, cross-resistance