He Yike, Liu Chang, Zhang Jiabo, Wang Gang, Liu Huixin, Peng Chu, Liu Xianhua, Wang Jiao
School of Environmental Science and Engineering, Tianjin University, Tianjin 300354, China; The Eighth Geological Brigade, Hebei Geological Prospecting Bureau, Qinhuangdao 066001, China.
National Marine Data Information Service, Tianjin 300401, China.
J Hazard Mater. 2025 Aug 15;494:138610. doi: 10.1016/j.jhazmat.2025.138610. Epub 2025 May 13.
Suspended particles are recognized as hotspots of antibiotic resistance genes (ARGs) in coastal waters. However, the dynamics of ARGs associated with suspended particles during sewage discharge into coastal environments remain poorly understood. This study simulated sewage influx into coastal waters using microcosms to investigate the decay dynamics of particle-associated (PA) and free-living (FL) ARGs. Results showed that four ARGs, including two sulfonamide resistance genes (sul1 and sul2) and two tetracycline resistance genes (tetB and tetG), exhibited significantly lower decay rates in the PA fraction than in the FL fraction. Specifically, bacterial decay (k = 0.96 day⁻¹) and horizontal gene transfer decay (k = 0.62 day⁻¹) were both slower in the PA fraction compared to the FL fraction (1.56 day⁻¹ and 1.98 day⁻¹, respectively). These results indicated that suspended particles slow down the decay of ARGs. Microbial community analysis revealed approximately 80 % similarity between sewage and seawater at day 0, but a marked increase in unique bacterial genera and unknown-source taxa was observed at day 15. These results suggest that sewage discharge rapidly alters the composition of native seawater communities. Furthermore, suspended particles harbored higher abundances of unknown-source bacteria and displayed stronger bacterial community interactions than the surrounding water. These findings advance our understanding of ARG persistence and microbial community dynamics, offering critical insights for understanding ARGs dissemination from wastewater discharge.
悬浮颗粒被认为是沿海水域抗生素抗性基因（ARGs）的热点。然而，在污水排入沿海环境过程中，与悬浮颗粒相关的ARGs动态仍知之甚少。本研究使用微观模型模拟污水流入沿海水域，以研究颗粒结合态（PA）和自由生活态（FL）ARGs的衰减动态。结果表明，包括两个磺胺抗性基因（sul1和sul2）和两个四环素抗性基因（tetB和tetG）在内的四种ARGs，在PA组分中的衰减率显著低于FL组分。具体而言，与FL组分（分别为1.56天⁻¹和1.98天⁻¹）相比，PA组分中的细菌衰减（k = 0.96天⁻¹）和水平基因转移衰减（k = 0.62天⁻¹）均较慢。这些结果表明，悬浮颗粒减缓了ARGs的衰减。微生物群落分析显示，在第0天污水和海水之间的相似度约为80%，但在第15天观察到独特细菌属和未知来源分类群显著增加。这些结果表明，污水排放迅速改变了原生海水群落的组成。此外，悬浮颗粒中未知来源细菌的丰度更高，并且与周围水体相比表现出更强的细菌群落相互作用。这些发现增进了我们对ARGs持久性和微生物群落动态的理解，为理解废水排放中ARGs的传播提供了关键见解。
