在一个健康的背景下,污水处理厂(WWTP)是保护水资源的核心。尽管如此,它们在预防抗菌素耐药性(AMR)传播方面的有效性仍然存在许多问题.大多数监测研究监测从WWTP流入物和流出物中提取的细胞内DNA(iDNA)中选定的抗生素抗性基因(ARG)和移动遗传元件(MGE)的水平和去除。胞外游离DNA(exDNA)在废水中的作用大多被忽视。本研究分析了用好氧颗粒污泥去除养分的全尺寸Nereda®反应器中ARG和MGE的转移。我们追踪了流入液的iDNA和exDNA池的组成和命运,污泥,和废水样本。宏基因组学被用来描述微生物组,抗性,以及iDNA和exDNA提取物的动员体签名。通过qPCR分析选择的ARG和MGE。从2,840个识别的ARG中,ARR-3基因(2%),tetC(1.6%),sul1(1.5%),oqxB(1.2%),在所有采样点和生物聚集体中,aph(3“)-Ib(1.2%)最丰富。假单胞菌,不动杆菌,气单胞菌,Acidovorax,Rhodoferax,链霉菌种群是污泥中ARGs的主要潜在宿主。在污水中,检测到478个电阻决定因素,其中89%来自反应器曝气过程中细胞裂解可能释放的exDNA。MGE和多个ARG共同定位在相同的细胞外遗传重叠群上。由于废水处理,细胞内总ARG减少了3-42%。然而,ermB和sul1基因分别增加2和1个log基因拷贝mL-1,从进水到出水的exDNA。在AMR监测中需要考虑exDNA部分,风险评估,和缓解策略。
In the One Health context, wastewater treatment plants (WWTPs) are central to safeguarding water resources. Nonetheless, many questions remain about their effectiveness in preventing antimicrobial resistance (AMR) dissemination. Most surveillance studies monitor the levels and removal of selected antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) in intracellular DNA (iDNA) extracted from WWTP influents and effluents. The role of extracellular free DNA (exDNA) in wastewater is mostly overlooked. This study analyzed the transfer of ARGs and MGEs in a full-scale Nereda® reactor removing nutrients with aerobic granular sludge. We tracked the composition and fate of the iDNA and exDNA pools of influent, sludge, and effluent samples. Metagenomics was used to profile the microbiome, resistome, and mobilome signatures of iDNA and exDNA extracts. Selected ARGs and MGEs were analyzed by qPCR. From 2,840 ARGs identified, the genes arr-3 (2%), tetC (1.6%), sul1 (1.5%), oqxB (1.2%), and aph(3\")-Ib (1.2%) were the most abundant among all sampling points and bioaggregates. Pseudomonas, Acinetobacter, Aeromonas, Acidovorax, Rhodoferax, and Streptomyces populations were the main potential hosts of ARGs in the sludge. In the effluent, 478 resistance determinants were detected, of which 89% were from exDNA potentially released by cell lysis during aeration in the reactor. MGEs and multiple ARGs were co-localized on the same extracellular genetic contigs. Total intracellular ARGs decreased 3-42% due to wastewater treatment. However, the ermB and sul1 genes increased by 2 and 1 log gene copies mL-1, respectively, in exDNA from influent to effluent. The exDNA fractions need to be considered in AMR surveillance, risk assessment, and mitigation strategies.