a State Key Laboratory of Pollution Control and Resource Reuse, Environmental Health Research Center, School of the Environment , Nanjing University , Nanjing , China.
J Environ Sci Health B. 2014;49(8):624-31. doi: 10.1080/03601234.2014.911594.
Tetracyclines are antibiotics commonly used in swine farms to treat disease and promote growth. However, there are growing concerns regarding the discharge of animal feces into the environment owing to the potential for development and dissemination of tetracycline resistance genes (TRGs). In this study, farming wastewater from one Chinese swine farm as well as river water from seven locations downstream of the farm was sampled. Polymerase chain reaction (PCR) showed that 12 TRGs, including six efflux pump genes (tet(B), tet(C), tet(D), tet(E), tet(G) and tet(L)), five ribosomal protection proteins (RPPs) genes (tet(O), tet(M), tet(Q), tet(W) and tet(S)), and one enzymatic modification gene (tet(X)), were present in all wastewater and river water samples. Quantitative real-time PCR (qPCR) showed that the abundance of tet(C), tet(X), tet(O), tet(M), tet(Q) and tet(W) decreased with downstream flow. Among the detected TRGs, tet(C) had the highest abundance, ranging from 459.5 copies/16S rRNA gene copies in wastewater to 33.8 copies/16S rRNA gene copies in river water samples collected from the last location. Furthermore, pig-specific Bacteroidales 16S rRNA genetic marker was quantified by qPCR to determine the level of fecal pollution in the river water. Bivariate correlation analysis confirmed that the total relative abundance of the six TRGs was significantly correlated with the level of swine feces in the aquatic environment (R(2) = 0.63, P < 0.05), suggesting that swine feces mainly contributed to the spread of TRGs in the river water.
四环素类抗生素常用于猪场治疗疾病和促进生长。然而，由于四环素耐药基因（TRGs）的发展和传播的可能性，动物粪便排放到环境中引起了越来越多的关注。在这项研究中，从中国一个猪场的养殖废水中以及从猪场下游的七个地点的河水中采集水样。聚合酶链反应（PCR）显示，所有废水和河水样本中都存在 12 个 TRGs，包括 6 个外排泵基因（tet(B)、tet(C)、tet(D)、tet(E)、tet(G)和 tet(L)）、5 个核糖体保护蛋白（RPPs）基因（tet(O)、tet(M)、tet(Q)、tet(W)和 tet(S)）和 1 个酶修饰基因（tet(X)）。定量实时 PCR（qPCR）显示，tet(C)、tet(X)、tet(O)、tet(M)、tet(Q)和 tet(W)的丰度随下游水流而降低。在所检测的 TRGs 中，tet(C)的丰度最高，范围从废水中的 459.5 拷贝/16S rRNA 基因拷贝到最后一个地点采集的河水中的 33.8 拷贝/16S rRNA 基因拷贝。此外，通过 qPCR 定量检测了猪特异性拟杆菌 16S rRNA 遗传标记，以确定河水中粪便污染的水平。双变量相关分析证实，六种 TRGs 的总相对丰度与水生环境中猪粪便的水平显著相关（R(2) = 0.63，P < 0.05），表明猪粪便主要导致了 TRGs 在河水中的传播。
