title: Distinguishing effects of ultraviolet exposure and chlorination on the horizontal transfer of antibiotic resistance genes in municipal wastewater.
abstract: Growing attention has been paid to the dissemination of antibiotic resistance genes (ARGs) in wastewater microbial communities; however, the disinfection processes, as microbial control technologies, have not been evaluated for their impacts on ARGs transfer. In this study, the effects of ultraviolet (UV) disinfection and chlorination on the frequency of ARGs transfer have been explored based on the conjugative transfer model between Gram-negative strains of E. coli. The results indicated that UV disinfection and chlorination exhibit distinct influences on the conjugative transfer. Low UV doses (up to 8 mJ/cm2) had little influence on the frequency of conjugative transfer, and UV exposure only decreased the bacterial number but did not change the cell permeability. By comparison, low chlorine doses (up to 40 mg Cl min/L) significantly promoted the frequency of conjugative transfer by 2-5-fold. The generated chloramine stimulated the bacteria and improved the cell permeability. More pilus were induced on the surface of conjugative cells, which acted as pathways for ARGs transfer. The frequency of ARG transfers was greatly suppressed by high doses of UV (>10 mJ/cm2) or chlorine (>80 mg Cl min/L).
authors: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 200092 Shanghai, China.
authors: Mei-Ting
authors: MT
authors: Guo
authors: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 200092 Shanghai, China.
authors: Qing-Bin
authors: QB
authors: Yuan
authors: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 200092 Shanghai, China.
authors: Jian
authors: J
authors: Yang
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D003227:Conjugation, Genetic; D004203:Disinfection; D004307:Dose-Response Relationship, Radiation; D004352:Drug Resistance, Microbial / Q000235:genetics* / Q000528:radiation effects; D004926:Escherichia coli / Q000235:genetics* / Q000528:radiation effects / Q000648:ultrastructure; D022761:Gene Transfer, Horizontal / Q000528:radiation effects*; D005798:Genes, Bacterial; D054879:Halogenation / Q000528:radiation effects*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D050296:Microbial Viability / Q000528:radiation effects; D014466:Ultraviolet Rays; D062065:Wastewater / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D007770:L-Lactate Dehydrogenase; D062065:Wastewater