title: Evaluation of five antibiotic resistance genes in wastewater treatment systems of swine farms by real-time PCR.
abstract: Antibiotics are widely used in livestock for infection treatment and growth promotion. Wastes from animal husbandry are a potential environmental source of antibiotic-insensitive pathogens, and the removal efficiency of the resistance genotypes in current wastewater treatment plants (WWTPs) is unknown. In this study, quantitative PCR was used for evaluating antibiotic resistance genes in wastewater treatment processes. Six wastewater treatment plants in different swine farms were included in this study, and five antibiotic resistance genes (ARGs) were tested for each treatment procedure. All of the tested ARGs including tetA, tetW, sulI, sulII, and blaTEM genes were detected in six swine farms with considerable amounts. The results showed that antibiotic resistance is prevalent in livestock farming. The ARG levels were varied by wastewater treatment procedure, frequently with the highest level at anaerobic treatment tank and lowest in the activated sludge unit and the effluents. After normalizing the ARG levels to 16S rRNA gene copies, the results showed that ARGs in WWTP units fluctuated partly with the quantity of bacteria. Regardless of its importance in biodegradation, the anaerobic procedure may facilitate bacterial growth thus increasing the sustainability of the antibiotic resistance genotypes. After comparing the copy numbers in influx and efflux samples, the mean removal efficiency of ARGs ranged between 33.30 and 97.56%. The results suggested that treatments in the WWTP could partially reduce the spread of antibiotic-resistant bacteria, and additional procedures such as sedimentation may not critically affect the removal efficiency.
authors: Section of Respiratory Therapy, Cheng Hsin General Hospital, Taipei, Taiwan, ROC.
authors: Chi-Wei
authors: CW
authors: Tao
authors: Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC. Electronic address: bmhsu@ccu.edu.tw.
authors: Bing-Mu
authors: BM
authors: Hsu
authors: Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC.
authors: Wen-Tsai
authors: WT
authors: Ji
authors: Department of Ophthalmology, Cheng Hsin General Hospital, Taipei, Taiwan, ROC.
authors: Tsui-Kang
authors: TK
authors: Hsu
authors: Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC.
authors: Po-Min
authors: PM
authors: Kao
authors: Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC; Dalin Junior High School, Chiayi, Taiwan, ROC.
authors: Chun-Po
authors: CP
authors: Hsu
authors: Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC.
authors: Shu-Min
authors: SM
authors: Shen
authors: Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC.
authors: Tzung-Yu
authors: TY
authors: Shen
authors: Department and Graduate School of Safety Health and Environmental Engineering, National Yunlin University of Science and Technology, Yunlin, Taiwan, ROC.
authors: Terng-Jou
authors: TJ
authors: Wan
authors: Department of Safety Health and Environmental Engineering, National Kaohsiung First University of Science and Technology, Kaohsiung, Taiwan, ROC.
authors: Yu-Li
authors: YL
authors: Huang
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D004352:Drug Resistance, Microbial / Q000235:genetics*; D005798:Genes, Bacterial; D060888:Real-Time Polymerase Chain Reaction; D013552:Swine; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000382:microbiology*
chemical_list: D062065:Wastewater
keywords: Antibiotic resistance genes; Removal efficiency; Swine farms; Wastewater treatment