title: Shift in antibiotic resistance gene profiles associated with nanosilver during wastewater treatment.
abstract: This study investigated the response of antibiotic resistance genes (ARGs) to nanosilver (Ag) in lab-scale nitrifying sequencing batch reactors (SBRs), compared to Ag(+)-dosed and undosed controls. Quantitative polymerase chain reaction (q-PCR) targeting sul1, tet(O), ermB and the class I integron gene intI1 and corresponding RNA expression did not indicate measureable effects of nanoAg or Ag(+) on abundance or expression of these genes. However, high-throughput sequencing based metagenomic analysis provided a much broader profile of gene responses and revealed a greater abundance of aminoglycoside resistance genes (mainly strA) in reactors dosed with nanoAg. In contrast, bacitracin and macrolide-lincosamide-streptogramin (MLS) resistance genes were more abundant in the SBRs dosed with Ag(+). The distinct ARG profiles associated with nanoAg and Ag(+) were correlated with the taxonomic composition of the microbial communities. This study indicates that nanoAg may interact with bacteria differently from Ag(+) during biological wastewater treatment. Therefore, it cannot necessarily be assumed that nanosilver behaves identically as Ag(+) when conducting a risk assessment for release into the environment.
authors: School of Environmental Science and Spatial Informatics, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China mayanjun@cumt.edu.cn.
authors: Yanjun
authors: Y
authors: Ma
authors: Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA 24061, USA.
authors: Jacob W
authors: JW
authors: Metch
authors: School of Marine Sciences, Sun Yat-sen University, Guangzhou 510006, China.
authors: Ying
authors: Y
authors: Yang
authors: Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA 24061, USA.
authors: Amy
authors: A
authors: Pruden
authors: Environmental Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, Hong Kong, China.
authors: Tong
authors: T
authors: Zhang
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000145:classification / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000235:genetics; D024881:Drug Resistance, Bacterial; D032023:Integrons; D055231:Lincosamides / Q000494:pharmacology; D018942:Macrolides / Q000494:pharmacology; D056186:Metagenomics; D058465:Nitrification; D012834:Silver / Q000494:pharmacology*; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology*; D018508:Water Purification
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D055231:Lincosamides; D018942:Macrolides; D012834:Silver; D062065:Wastewater
keywords: Antibiotic resistance genes; biological wastewater treatment; metagenomic analysis; nanosilver; sequencing batch reactors