title: Effect of chlorination and ultraviolet disinfection on tetA-mediated tetracycline resistance of Escherichia coli.
abstract: Antibiotic-resistant bacteria are an emerging threat to public health during drinking water consumption and reclaimed water reuse. Several studies have shown that the proportions of antibiotic-resistant bacteria in waters may increase when exposed to low doses of UV light or chlorine. In this study, inactivation of tetracycline-resistant Escherichia coli and antibiotic-sensitive E. coli by UV disinfection and chlorination was compared to determine the tolerance of tetracycline-resistant E. coli to UV light and chlorine, and tetracycline resistance of a tetracycline-resistant E. coli population was studied under different doses of the disinfectants. Our results showed that relative to antibiotic-sensitive E. coli, tetracycline-resistant E. coli had the same tolerance to UV light and a potentially higher tolerance to chlorination. The mortality frequency distributions of tetracycline-resistant E. coli exposed to tetracycline were shifted by both chlorination and UV disinfection. When compared to the hemi-inhibitory concentrations (IC(50)) of tetracycline-resistant E. coli with no exposure to UV or chlorination, the IC(50) of tetracycline-resistant E. coli treated with tetracycline was 40% lower when inactivation by UV light or chlorination reached 3-log but was 1.18 times greater when inactivation by chlorination reached 4.3-log. Chlorination applied to drinking water or reclaimed water treatment may increase the risk of selection for highly tetracycline-resistant E. coli.
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China.
authors.forename: Jing-Jing
authors.initials: JJ
authors.lastname: Huang
authors.forename: Hong-Ying
authors.initials: HY
authors.lastname: Hu
authors.forename: Yin-Hu
authors.initials: YH
authors.lastname: Wu
authors.forename: Bin
authors.initials: B
authors.lastname: Wei
authors.forename: Yun
authors.initials: Y
authors.lastname: Lu
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D017920:Antiporters / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D004202:Disinfectants / Q000633:toxicity; D004203:Disinfection / Q000379:methods*; D060766:Drinking Water / Q000737:chemistry / Q000382:microbiology; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D054879:Halogenation; D013752:Tetracycline / Q000494:pharmacology; D013753:Tetracycline Resistance / Q000235:genetics / Q000528:radiation effects*; D014466:Ultraviolet Rays; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods*
chemical_list: D000900:Anti-Bacterial Agents; D017920:Antiporters; D001426:Bacterial Proteins; D004202:Disinfectants; D060766:Drinking Water; C079051:tetA protein, Bacteria; D013752:Tetracycline