摘要
      集中式污泥处理厂（CSTP）被认为是抗生素抗性基因（ARGs）的强大热点。然而，关于细胞内和细胞外ARGs（iARGs和eARGs）命运以及耐药宿主功能的知识差距限制了CSTP耐药组的风险评估和管理。在这里，使用定量宏基因组方法，在三个全尺寸CSTP中系统地探索了iARGs和eARGs在处理单元之间的流动以及ARG宿主的分析。我们发现29%的污泥ARG可以被去除，其中iARGs在产生的生物固体中占主导地位。处理过程显著影响iARG和eARG丰度的变化，而在CSTP中观察到iARGs和eARGs之间的组成没有显著差异。295个回收的基因组中有15%被鉴定为抗生素抗性宿主，其中放线菌倾向于编码多重耐药性。ARG宿主的关键功能与生物有机物（如碳水化合物）的去除有关。某些抗性机制与功能性状之间也存在关系，表明ARGs可能参与了污泥处理中微生物的生理过程。这些发现为差异耐药性变异和宿主功能提供了重要的见解，这对CSTP中抗生素耐药性的管理至关重要。
Abstract
Centralized sludge treatment plants (CSTPs) are implicated as strong hotspots of antibiotic resistance genes (ARGs). However, the knowledge gap on the fate of intracellular and extracellular ARGs (iARGs and eARGs), and the functionality of resistant hosts limit risk assessment and management of CSTP resistome. Here, the flow of iARGs and eARGs across treatment units and analyses of ARG hosts were systematically explored in three full-scale CSTPs using quantitative metagenomic approaches. We found that 29% of sludge ARGs could be removed, with iARGs being dominant in the produced biosolids. The treatment process significantly affected the variations of iARG and eARG abundance while no significant difference in composition between iARGs and eARGs was observed in CSTPs. 15% of 295 recovered genomes were identified as antibiotic-resistant hosts, among which Actinobacteriota tended to encode multiple resistance. The key functions of ARG hosts were relative to the biological organic removal (e.g., carbohydrates). There also existed relationships between certain resistance mechanisms and functional traits, indicating that ARGs might take part in the physiological process of microorganisms in the sludge treatment. These findings provide important insight into the differential resistome variations and host functionality, which would be crucial in the management of antibiotic resistance in CSTPs.

https://www.sciencedirect.com/science/article/abs/pii/S0043135422008405