摘要
      抗生素耐药性是一个全球性的公共卫生问题。猪使用抗生素使猪废水（SW）成为抗生素抗性基因（ARGs）的蓄水池。SW通常在中国北方的中小型养猪场的三室厌氧池（3-CAP）中储存和处理。然而，如果农民将SW作为液体有机肥料施用到农田中，那么在3-CAP处理过程中，SW中ARGs的存在可能会导致ARGs扩散到环境中。本研究调查了在3-CAP处理期间，SW中ARGs在四个季节的分布和变化，并分析了ARGs与细菌表型之间的相关性，以及水的物理化学参数。结果显示，3-CAP治疗后，ARG丰度在4月（47%）、10月（47%和12月（62%）显著下降，但在5月（43%）和8月（73%）增加。进水和其他SW样品中的ARG拷贝数从4月的107拷贝/mL显著增加到10月的109拷贝/mL，并在12月保持不变。ARG丰度的增加不如细菌种群的增长快，导致10月和12月的相对丰度较低。细菌群落具有更多的sul1和tetM基因，这些基因也与可移动的遗传元素呈正相关。3-CAP治疗后，16%的抗生素和60%的重金属被去除，两者与ARGs的相关性较弱。预测的表型显示，革兰氏阳性（G+）和革兰氏阴性（G-）细菌携带ARGs的能力不同。G+细菌比G-细菌携带更多的ARG。这项研究揭示了在不同季节3-CAP处理后，SW中ARGs的持久性。在适当的月份应用软件将减少ARG对环境的传播。
Abstract
Antibiotic resistance is a global public health concern. Antibiotic usage in pigs makes swine wastewater (SW) a reservoir for antibiotic resistance genes (ARGs). SW is usually stored and treated in a three-chamber anaerobic pond (3-CAP) in medium and small pig farms in northern China. However, the yet unexplored presence of ARGs in SW during 3-CAP treatment may result in ARGs spreading into the environment if farmers apply SW to farmland as a liquid organic fertilizer. This study investigated the profiles of and changes in ARGs in SW during its treatment in 3-CAP over four seasons and analyzed the correlation between ARGs and bacterial phenotypes, along with the physicochemical parameters of the water. The results revealed that ARG abundance decreased considerably after 3-CAP treatment in April (47%), October (47%), and December (62%) but increased in May (43%) and August (73%). The ARG copies in the influent and other SW samples increased significantly from 107 copies/mL in April to 109 copies/mL in October and were maintained in December. The increase in ARG abundance was not as rapid as the growth of the bacterial population, resulting in lower relative abundance in October and December. Bacterial communities possessed more sul1 and tetM genes, which were also positively correlated with mobile genetic elements. After the 3-CAP treatment, 16% of antibiotics and 60% of heavy metals were removed, and both had a weak correlation with ARGs. Predicted phenotypes showed that gram-positive (G+) and gram-negative (G−) bacteria have different capacities for carrying ARGs. G+ bacteria carry more ARGs than G− bacteria. This study revealed the persistence of ARGs in SW after 3-CAP treatment over different seasons. Applying SW in the proper month will mitigate ARG dissemination to the environment.

https://www.sciencedirect.com/science/article/abs/pii/S0013935122018229