title: Occurrence, abundance and elimination of class 1 integrons in one municipal sewage treatment plant.
abstract: Integrons are elements that encode a site-specific recombination system that recognizes and captures mobile gene cassettes and are closely related to multiple resistances of environmental microorganisms. This study was undertaken to determine the efficiency of an activated sludge process to remove integrons. The prevalence and characteristics of class 1 integrons were investigated for bacterial species isolated from the activated sludge of Nanjing Jiangxinzhou sewage treatment plant (STP, China). A total of 189 bacterial strains were isolated from influent water, activated sludge and effluent water, and PCR-RFLP (Polymerase chain reaction--restriction fragment length polymorphism) of 16S rRNA gene showed that the isolated bacteria were Escherichia coli, Aeromonas veronii, Klebsiella spp., Aeromonas salmonicida and Aeromonas media. PCRs showed that 57 isolates contained class 1 integronase gene intI1. The integron detection frequency in the isolated strains was 20.4% for influent, 30.9% for activated sludge and 38.9% for effluent. Quantitative real-time PCR assay showed that the abundance of integrons in effluent was higher than that in influent. This study indicates that class 1 integrons are wide-spread in STPs which might be involved in multiple resistances in the activated sludge characterized by high biomass and biodiversity.
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Road, Nanjing, 210046, China.
authors: Liping
authors: L
authors: Ma
authors: Xu-Xiang
authors: XX
authors: Zhang
authors: Shupei
authors: S
authors: Cheng
authors: Zongyao
authors: Z
authors: Zhang
authors: Peng
authors: P
authors: Shi
authors: Bo
authors: B
authors: Liu
authors: Bing
authors: B
authors: Wu
authors: Yan
authors: Y
authors: Zhang
mesh_terms: D000900:Anti-Bacterial Agents / Q000633:toxicity; D001419:Bacteria / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D002947:Cities; D024881:Drug Resistance, Bacterial / Q000235:genetics; D032023:Integrons / Q000235:genetics*; D010802:Phylogeny; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology; D014865:Waste Disposal, Fluid; D014871:Water Microbiology; D014873:Water Pollutants / Q000032:analysis*
chemical_list: D000900:Anti-Bacterial Agents; D012722:Sewage; D014873:Water Pollutants