title: Microbial selectivity of UV treatment on antibiotic-resistant heterotrophic bacteria in secondary effluents of a municipal wastewater treatment plant.
abstract: Little is known about the microbial selectivity of UV treatment for antibiotic resistant bacteria, and the results of limited studies are conflicting. To understand the effect of UV disinfection on antibiotic resistant bacteria, both total heterotrophic bacteria and antibiotic resistant bacteria (including cephalexin-, ciprofloxacin-, erythromycin-, gentamicin-, vancomycin-, sulfadiazine-, rifampicin-, tetracycline- and chloramphenicol-resistant bacteria) were examined in secondary effluent samples from a municipal wastewater treatment plant. Bacteria resistant to both erythromycin and tetracycline were chosen as the representative of multiple-antibiotic-resistant bacteria and their characteristics after UV treatment were also investigated. UV disinfection results in effective inactivation for total heterotrophic bacteria, as well as all antibiotic resistant bacteria. After UV treatment at a fluence of 5 mJ/cm(2), the log reductions of nine types of antibiotic resistant bacteria varied from 1.0 ± 0.1 to 2.4 ± 0.1. Bacteria resistant to both erythromycin and tetracycline had a similar fluence response as did total heterotrophic bacteria. The findings suggest that UV disinfection could eliminate antibiotic resistance in wastewater treatment effluents and thus ensure public health security. Our experimental results indicated that UV disinfection led to enrichment of bacteria with resistance to sulfadiazine, vancomycin, rifampicin, tetracycline and chloramphenicol, while the proportions of cephalexin-, erythromycin-, gentamicin- and ciprofloxacin-resistant bacteria in the wastewater decreased. This reveals the microbial selectivity of UV disinfection for antibiotic resistant bacteria.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 200092 Shanghai, China; State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (MARC), Tsinghua University, 100084 Beijing, China. Electronic address: guomeiting@tongji.edu.cn.
authors.forename: Mei-Ting
authors.initials: MT
authors.lastname: Guo
authors.forename: Qing-Bin
authors.initials: QB
authors.lastname: Yuan
authors.forename: Jian
authors.initials: J
authors.lastname: Yang
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects / Q000528:radiation effects*; D004352:Drug Resistance, Microbial / Q000528:radiation effects*; D014466:Ultraviolet Rays; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods* / Q000592:standards
chemical_list: D000900:Anti-Bacterial Agents
keywords: Antibiotic resistant bacteria; Inactivation; Microbial selectivity; Multiple-antibiotic resistance; UV disinfection