title: Propensity of activated sludge to amplify or attenuate tetracycline resistance genes and tetracycline resistant bacteria: a mathematical modeling approach.
abstract: The overall goal of this study was to quantify the propensity of the activated sludge (AS) process at three wastewater treatment plants (WWTP) to amplify or attenuate tetracycline resistant bacteria (TRB) and tetracycline resistance genes (TRG). Accordingly, the abundance and fraction of TRB and seven TRG in different unit operations of these WWTP were analytically measured and modeled using a mass balance approach widely used for AS design. Based on the model, the AS process of the different WWTP neither amplified nor attenuated the TRB and TRG fractions. Of the TRG tested, the ribosomal protection genes, tet(O) and tet(W) were the most abundant, along the treatment train of the WWTP, on all sampling dates and sampling locations. Significant amounts of TRB and TRG were discharged in the effluent streams. Notably, in selected samples, the fraction of TRB increased in response to ultraviolet disinfection of treated wastewater compared to chlorination. This study therefore implicates wastewater treatment processes as significant point sources of tetracycline resistance determinants to the environment, and provides a mathematical basis to compute the production capacity of these determinants in the AS process.
authors.affiliation: Department of Earth and Environmental Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA.
authors.forename: Sungpyo
authors.initials: S
authors.lastname: Kim
authors.forename: Hongkeun
authors.initials: H
authors.lastname: Park
authors.forename: Kartik
authors.initials: K
authors.lastname: Chandran
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D024881:Drug Resistance, Bacterial; D005798:Genes, Bacterial; D008954:Models, Biological; D012722:Sewage / Q000382:microbiology*; D013752:Tetracycline / Q000494:pharmacology*; D013753:Tetracycline Resistance / Q000235:genetics*; D014865:Waste Disposal, Fluid; D018508:Water Purification
chemical_list: D000900:Anti-Bacterial Agents; D012722:Sewage; D013752:Tetracycline