环境中抗生素抗性基因的增加可能对公众健康构成威胁。本研究的目的是调查中国东部杭州8个畜牧场四环素（tet）和磺胺（sul）抗性基因的浓度和多样性。将10个tet基因（tetA，tetB，tetC，tetG，tetL，tetM，tetO，tetQ，tetW和tetX），两个sul基因（sulI和sulII）和一个与抗生素抗性基因相关的流动遗传因子[ intI1）]通过实时聚合酶链式反应进行定量。不同规模的猪，鸡，鸭农场tet和sul基因浓度无明显差异（P> 0.05）。在粪肥和废水样品中，外排泵基因tetG除外，核糖体保护蛋白基因（tetQ，tetM，tetW和tetO）的平均浓度比大多数外排泵基因（tetA，tetB，tetC和tetL）和酶修饰基因（tetX） （P <0.05）平均浓度高，与tetM无显着差异。即使处理后，大多数ARG在废水泻湖中的相对浓度也比粪肥中的相对浓度高。尽管三个核糖体保护蛋白基因（tetQ，tetW和tetO）具有较高的相对浓度，但是在猪场的整个废水处理过程中减少（P <0.05）。废水处理后，tetG，sulI和sulII的相对浓度增加，这三个基因的去除与intI1基因呈正相关（tetG：R2 = 0.60，P <0.05; sulI：R2 = 0.72，P <0.05 ; sulII：R2 = 0.62，P <0.05），提示intI1可能参与其增殖。 tetM和sulII基因在养猪场和养鸭场粪肥样品中差异极显着（P <0.001）。系统发育分析表明，在农场中，牛群比猪场更多样化。另外，在猪和鸭农场中都保留了sulII序列。这是第一个详细研究动物粪肥和农业废水处理系统中特定ARG的相对浓度的综合研究，可为管理农业活动带来的抗生素耐药性提供帮助。

      Increases of antibiotic resistance genes in the environment may pose a threat to public health. The purpose of this study was to investigate the abundance and diversity of tetracycline (tet) and sulfonamide (sul) resistance genes in eight livestock farms in Hangzhou, eastern China. Ten tet genes (tetA, tetB, tetC, tetG, tetL, tetM, tetO, tetQ, tetW, and tetX), two sul genes (sulI and sulII), and one genetic element associated with mobile antibiotic resistance genes [class 1 integron (intI1)] were quantified by real-time polymerase chain reaction. No significant difference was found in the abundance of the tet and sul genes in various scales of pig, chicken, and duck farms (P > 0.05). The average abundance of ribosomal protection protein genes (tetQ, tetM, tetW, and tetO) in the manure and wastewater samples was higher than most of the efflux pump genes (tetA, tetB, tetC, and tetL) and enzymatic modification gene (tetX) (P < 0.05), except for efflux pump gene tetG, which was abundant and showed no difference from tetM. Most ARGs had higher relative abundance in the wastewater lagoon than in manures even after treatment. Although the three ribosomal protection protein genes (tetQ,tetW, and tetO) had higher relative abundance, numbers were reduced during the complete wastewater treatment process in pig farms (P < 0.05). The relative abundance of tetG, sulI, and sulII increased after the wastewater treatment and the removal of these three genes exhibited significant positive correlations with the intI1 gene (tetG: R2 = 0.60, P < 0.05; sulI:R2 = 0.72, P < 0.05; sulII: R2 = 0.62, P < 0.05), suggesting that intI1 may be involved in their proliferation. As for tetM and sulII genes, a highly significant difference was found in manure samples between pig farms and duck farms (P < 0.001). Phylogenetic analysis showed thattetM was more diverse in duck farms than in pig farms. Additionally, sulII sequence was conserved both in pig and duck farms. This is the first comprehensive study to detail the relative abundance of specific ARGs in animal manures and agricultural wastewater treatment systems, potentially providing knowledge for managing antibiotic resistance emanating from agricultural activities.

http://www.sciencedirect.com/science/article/pii/S0160412013001992