title: UV light tolerance and reactivation potential of tetracycline-resistant bacteria from secondary effluents of a wastewater treatment plant.
abstract: Tetracycline-resistant bacteria (TRB) are of concern as emerging microbial contaminants in reclaimed water. To understand the effects of UV disinfection on TRB, both inactivation and reactivation profiles of TRB, as well as 16 tetracycline-resistant isolates from secondary effluent, were characterized in this study. The inactivation ratio of TRB was significantly lower (3.0-log) than that of heterotrophic bacteria (>4.0-log) in the secondary effluent. Additionally, the proportion of TRB significantly increased from 1.65% to 15.51% under 20mJ/cm(2) ultraviolet (UV) exposure. The inactivation rates of tetracycline-resistant isolates ranged from 0.57/s to 1.04/s, of which tetracycline-resistant Enterobacter-1 was the most tolerant to UV light. The reactivation of TRB, tetracycline-resistant isolated strains, as well as heterotrophic bacteria commonly occurred in the secondary effluent even after 20mJ/cm(2) UV exposure. The colony forming ability of TRB and heterotrophic bacteria reached 3.2-log and 3.0-log under 20mJ/cm(2) UV exposure after 22hr incubation. The final inactivation ratio of tetracycline-resistant Enterobacter-1 was 1.18-log under 20mJ/cm(2) UV exposure after 22hr incubation, which is similar to those of TRB (1.18-log) and heterotrophic bacteria (1.19-log). The increased proportion of TRB and the reactivation of tetracycline-resistant enterobacteria in reclaimed water could induce a microbial health risk during wastewater reuse.
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control, School of Environment, Tsinghua University, Beijing 100084, China; China Power Engineering Consulting Group Co., LTD., Beijing 100120, China. Electronic address: jjhuang@cpecc.net.
authors.forename: Jing-Jing
authors.initials: JJ
authors.lastname: Huang
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control, School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Jinying
authors.initials: J
authors.lastname: Xi
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control, School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: hyhu@tsinghua.edu.cn.
authors.forename: Hong-Ying
authors.initials: HY
authors.lastname: Hu
authors.affiliation: College of Environmental Science and Engineering, Hohai University, Nanjing 210098, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.affiliation: College of Environmental Science and Engineering, Hohai University, Nanjing 210098, China.
authors.forename: Sun-Qin
authors.initials: SQ
authors.lastname: Lu
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control, School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Tang
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control, School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Yu-Chen
authors.initials: YC
authors.lastname: Pang
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000528:radiation effects*; D004203:Disinfection / Q000379:methods*; D013752:Tetracycline / Q000494:pharmacology*; D013753:Tetracycline Resistance; D014466:Ultraviolet Rays; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000382:microbiology*
chemical_list: D013752:Tetracycline; D062065:Wastewater
keywords: Dark repair; Inactivation; Reclaimed water; Tetracycline-resistant bacteria; UV disinfection