title: Occurrence of tetracycline-resistant fecal coliforms and their resistance genes in an urban river impacted by municipal wastewater treatment plant discharges.
abstract: Antibiotic resistance of fecal coliforms in an urban river poses great threats to both human health and the environment. To investigate the occurrence and distribution of antibiotic resistant bacteria in an urban river, water samples were collected from the Chanhe River in Xi'an, China. After membrane filtration of water samples, the tetracycline resistance rate of fecal coliforms and their resistance genes were detected by plating and polymerase chain reaction (PCR), respectively. We found that fecal coliforms were generally resistant to tetracycline and saw average resistance rates of 44.7%. The genes tetA and tetB were widely detected, and their positive rate was 60%-100% and 40%-90%, respectively. We found few strains containing tetC, tetK, tetQ and tetX, and we did not identify any strains containing tetG, tetM or tetO. The prevalence of tetA and tetB over other genes indicated that the main mechanism for resistance to tetracycline is by changes to the efflux pump. Our analysis of the types and proportion of tetracycline resistance genes in the Chanhe River at locations upstream and downstream of the urban center suggests that the increased number of tetracycline-resistant fecal coliforms and spatial variation of tetracycline resistance genes diversity were related to municipal wastewater treatment plant discharge.
authors.affiliation: a Key Lab of Northwest Water Resource , Environment and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology , Xi'an , China.
authors.forename: Chong-Miao
authors.initials: CM
authors.lastname: Zhang
authors.forename: Cong
authors.initials: C
authors.lastname: Du
authors.forename: Huan
authors.initials: H
authors.lastname: Xu
authors.forename: Yan-Hui
authors.initials: YH
authors.lastname: Miao
authors.forename: Yan-Yan
authors.initials: YY
authors.lastname: Cheng
authors.forename: Hao
authors.initials: H
authors.lastname: Tang
authors.forename: Jin-Hong
authors.initials: JH
authors.lastname: Zhou
authors.forename: Xiao-Chang
authors.initials: XC
authors.lastname: Wang
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry; D017920:Antiporters / Q000032:analysis*; D001426:Bacterial Proteins / Q000032:analysis*; D002681:China; D002947:Cities; D004755:Enterobacteriaceae / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology*; D006801:Humans; D045483:Rivers / Q000737:chemistry / Q000382:microbiology*; D013752:Tetracycline / Q000032:analysis / Q000737:chemistry; D013753:Tetracycline Resistance / Q000235:genetics*; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D017920:Antiporters; D001426:Bacterial Proteins; D013752:Tetracycline; D062065:Wastewater; C079051:tetA protein, Bacteria
keywords: Fecal coliforms; plant discharges; tetracycline resistance; urban river; wastewater treatment