Amr in Food, Water and the Environment Antibiotics and Resistance Genes in Wastewater Treatment Plants

T he dissemination of antibiotic resistance genes (ARGs) carried by antibiotic-resistant bacteria (ARB) and their threats to public health have attracted concerns worldwide in the recent years (1). A number of organizations and governments have enhanced their monitoring schemes of ARB and ARGs, including the World Health Organization (2), the Public Health Agency of Canada, the Houses of Parliament of United Kingdom and the White House in the United States. Besides those concerns on antibiotic resistance in clinical environments, interest has also arisen in ARGs entering the environment. Up until now, ARGs have been widely detected in various environments, including soil (3), water (4), and sediments (5), where they have the potential to be transferred from host bacteria to pathogens by horizontal gene transfer (HGT). ARGs are now regarded as emerging pollutants and their dissemination in the environment has attracted wide attention. However, the source and fate of ARGs in the environment is still not fully understood yet. Wastewater treatment plants (WWTPs) are among the main anthropogenic sources of ARGs discharged into the environment. The widely applied biological treatment process, such as activated sludge, creates favourable conditions for ARGs development and HGT under the sub-inhibitory antibiotic concentrations.