title: Characterization of microbial community and antibiotic resistance genes in activated sludge under tetracycline and sulfamethoxazole selection pressure.
abstract: To investigate the microbial community characteristics, antibiotic resistance genes (ARGs), and bioreactor effluent quality change under tetracycline (TC) and sulfamethoxazole (SMX) selection pressure, sequencing batch reactors (SBRs) were used with environmentally relevant concentration and high-level of TC and SMX concentrations (0, 5ppb, 50ppb and 10ppm). Chemical oxygen demand (COD) and ammonia nitrogen (NH4(+)N) removals appeared unchanged (p>0.05) with 5 and 50ppb, but decreased significantly with 10ppm (p<0.05). Extracellular polymeric substances (EPS) concentrations increased significantly with increasing TC or SMX concentrations (p<0.05). High-throughput 16S rRNA gene sequencing results suggested that Proteobacteria, Actinobacteria and Bacteroidetes were the three most abundant phyla in sludge samples. The Actinobacteria percentages increased with increasing TC or SMX concentration, while Proteobacteria and Bacteroidetes decreased. The microbial diversity achieved its maximum at 5ppb and decreased with higher concentrations. The total ARGs abundances in sludge increased with addition of TC or SMX, and the higher relative abundances were in the order of sul1>tetG>sul2>tetA>intI1>tetS>tetC. Pearson correlation analysis showed most ARGs (tetA, tetC, tetG, tetK, tetM, sul1) were significantly correlated with intI1 (p<0.01).
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China. Electronic address: jjgeng@nju.edu.cn.
authors.forename: Jinju
authors.initials: J
authors.lastname: Geng
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China.
authors.forename: Haijun
authors.initials: H
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China.
authors.forename: Hongqiang
authors.initials: H
authors.lastname: Ren
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China.
authors.forename: Ke
authors.initials: K
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China.
authors.forename: Lili
authors.initials: L
authors.lastname: Ding
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D019149:Bioreactors / Q000382:microbiology; D004352:Drug Resistance, Microbial / Q000235:genetics*; D005798:Genes, Bacterial; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology*; D013420:Sulfamethoxazole / Q000494:pharmacology; D013752:Tetracycline / Q000494:pharmacology; D013753:Tetracycline Resistance / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D012722:Sewage; D013752:Tetracycline; D013420:Sulfamethoxazole
keywords: Activated sludge; Antibiotic resistance genes; Microbial community; Sulfamethoxazole; Tetracycline