Microcosm experiments revealed resistome coalescence of sewage treatment plant effluents in river environment

Chang Liu; Xin Shan; Yuxin Zhang; Liuting Song; Haiyang Chen

doi:10.1016/j.envpol.2023.122661

Microcosm experiments revealed resistome coalescence of sewage treatment plant effluents in river environment

Environ Pollut. 2023 Dec 1:338:122661. doi: 10.1016/j.envpol.2023.122661. Epub 2023 Sep 29.

Authors

Chang Liu¹, Xin Shan¹, Yuxin Zhang¹, Liuting Song¹, Haiyang Chen²

Affiliations

¹ Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education; College of Water Sciences, Beijing Normal University, No 19, Xinjiekouwai Street, Beijing, 100875, China.
² Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education; College of Water Sciences, Beijing Normal University, No 19, Xinjiekouwai Street, Beijing, 100875, China. Electronic address: chen.haiyang@bnu.edu.cn.

PMID: 37778491
DOI: 10.1016/j.envpol.2023.122661

Abstract

Sewage treatment plant (STP) effluents are important contributors of antibiotic resistance (AR) pollution in rivers. Effluent discharging into rivers causes resistome coalescence. However, their mechanisms and dynamic processes are poorly understood, especially for the effects of dilution, diffusion, and sunlight-induced attenuation on coalescence. In this study, we have constructed microcosmic experiments based on in-situ investigation to explore these issues. The first batch experiment revealed the effects of dilution and diffusion. The coverage of water coalesced resistomes ranged 66.26∼152.18 × /Gb and was positively correlated with effluent volume (Mann-Kendall test, p < 0.01). Principal coordinate analysis (PCoA) and source tracking analysis demonstrated that dilution and diffusion stepwise reduced AR pollution. The second batch experiment explored the temporal dynamics and sunlight attenuation on coalesced resistomes. Under natural light, the coverage and diversity of water resistomes posed decreasing trends, primarily attributed to drastic erasure of effluent traces. The proportion of effluent-specific ARGs in coalesced resistomes significantly declined over time (Spearman's r = -0.83 and -0.94 in coverage and richness). While under dark condition, the coverage and diversity increased. Sunlight radiation intensified the interactions between water and sediment resistomes, as evidenced by more shared ARGs and less dissimilarities across niches. Network analysis, metagenome-assembled genome (MAG) analysis and variation partitioning analysis (VPA) showed that microbiome controlled resistome coalescence, explaining 56.5% and 58.4% of resistomes in water and sediment, respectively. Biotic and abiotic factors synergistically explained 40% of water resistomes. This study offers a comprehensive understanding of AR transmission and provides theoretical bases for grasping AR pollution and developing effective suppression strategies.

Keywords: Antibiotic resistance genes; Dilution and diffusion; Metagenomic analysis; Resistome coalescence; Sunlight-induced attenuation.

MeSH terms

Anti-Bacterial Agents* / pharmacology
Drug Resistance, Microbial / genetics
Genes, Bacterial
Rivers
Sewage*
Water

Substances

Sewage
Anti-Bacterial Agents
Water