Antibiotic Resistance Elements in Wastewater Treatment Plants: Scope and Potential Impacts

Abstract

Antibiotic resistance is considered to be one of the most significant public health concerns of the twenty-first century. Although traditionally the propagation of antibiotic resistance was considered to be limited to hospitals and other clinical environments, there is a growing realization that it is also associated with anthropogenically impacted environmental reservoirs. Wastewater treatment plants are considered to be significant reservoirs of antibiotic resistance because they combine extremely high levels of fecal-and environmental-derived bacteria with residual concentrations of antibiotic compounds believed to induce selection. These bacteria are primarily congregated in dense biofilms that are “hot spots” for horizontal gene transfer, which can facilitate inter-and intraspecies transfer of antibiotic genes, potentially resulting in the development of multidrug-resistant strains. Several studies have demonstrated that although wastewater treatment plants significantly reduce bacterial concentrations, relatively high levels of antibiotic-resistant bacteria and resistance genes are still present in effluents released to aquatic and soil environments and that under certain circumstances these resistance elements may persist for long periods of time in downstream