摘要

    抗生素抗性细菌（ARB）及其基因（ARG）已被公认为是重要的新兴环境污染物。当污泥被回收到农田中时，污水污泥中的ARB和ARGs可以通过食物链传给人类，这使得污泥处理成为控制ARB和ARGs向环境释放的关键。这项研究调查了英国两家污水处理厂污水污泥的全面厌氧消化（AD）过程中抗生素抗性大肠杆菌和大量抗生素抗性基因（ARG）的命运，并评估了热水解（TH）的影响对他们的丰富和多样性的待遇。使用单基因定量（q）PCR计算了13个ARG和I类整合子基因intI1的绝对丰度。高通量qPCR分析还用于确定370个ARG和流动遗传元件（MGE）的相对丰度。结果显示，TH将所有测试的ARG和intI1的绝对丰度降低了10–12,000倍。在随后的AD之后，在许多ARG中观察到反弹作用。未经预处理的AD期间ARG的命运是可变的。除大环内酯抗性基因（在两种植物中均富集）以及四环素和糖肽抗性基因（在使用TH的植物中富集）外，大多数ARGs和MGE的相对丰度均降低或波动。在污泥处理过程中，两种植物的ARGs和MGEs的多样性均降低。主坐标分析表明，根据处理步骤可以清楚地区分ARG，而消化污泥中的MGE则可以根据地点进行聚类。这项研究对ARG，MGE和抗药性大肠杆菌的命运进行了全面的消化内分析，并强调了AD的有效性，特别是当TH用作预处理时，降低了大多数ARG和MGE的丰度。污泥并防止其释放到环境中。

    Antibiotic resistant bacteria (ARB) and their genes (ARGs) have become recognised as significant emerging environmental pollutants. ARB and ARGs in sewage sludge can be transmitted back to humans via the food chain when sludge is recycled to agricultural land, making sludge treatment key to control the release of ARB and ARGs to the environment. This study investigated the fate of antibiotic resistant Escherichia coli and a large set of antibiotic resistance genes (ARGs) during full scale anaerobic digestion (AD) of sewage sludge at two U.K. wastewater treatment plants and evaluated the impact of thermal hydrolysis (TH) pre-treatment on their abundance and diversity. Absolute abundance of 13 ARGs and the Class I integron gene intI1 was calculated using single gene quantitative (q) PCR. High through-put qPCR analysis was also used to determine the relative abundance of 370 ARGs and mobile genetic elements (MGEs). Results revealed that TH reduced the absolute abundance of all ARGs tested and intI1 by 10–12,000 fold. After subsequent AD, a rebound effect was seen in many ARGs. The fate of ARGs during AD without pre-treatment was variable. Relative abundance of most ARGs and MGEs decreased or fluctuated, with the exception of macrolide resistance genes, which were enriched at both plants, and tetracyline and glycopeptide resistance genes which were enriched in the plant employing TH. Diversity of ARGs and MGEs decreased in both plants during sludge treatment. Principal coordinates analysis revealed that ARGs are clearly distinguished according to treatment step, whereas MGEs in digested sludge cluster according to site. This study provides a comprehensive within-digestor analysis of the fate of ARGs, MGEs and antibiotic resistant E. coli and highlights the effectiveness of AD, particularly when TH is used as a pre-treatment, at reducing the abundance of most ARGs and MGEs in sludgeand preventing their release into the environment.

    https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0237283