Removal of intracellular and extracellular antibiotic resistance genes and virulence factor genes using electricity-intensified constructed wetlands

• Published in: Journal of hazardous materials 2024-08, Vol.475, p.134749, Article 134749
• Main Authors: Yu, Kaifeng, Hei, Shenglei, Li, Peng, Chen, Ping, Yang, Jinghan, He, Yiliang
• Format: Article
• Language: English
• Subjects: Antibiotic resistance genes; Constructed wetlands; Microbial electrolysis cell; Pathogens; Virulence factor genes
• ISSN: 0304-3894; 1873-3336; 1873-3336
• DOI: 10.1016/j.jhazmat.2024.134749

Constructed wetland (CW) is considered a promising technology for the removal of emerging contaminants. However, its removal performance for antibiotic resistance genes (ARGs) is not efficient and influence of virulence factor genes (VFGs) have not been elucidated. Here, removal of intracellular and extracellular ARGs as well as VFGs by electricity-intensified CWs was comprehensively evaluated. The two electrolysis-intensified CWs can improve the removal of intracellular ARGs and MGEs to 0.96- and 0.85-logs, respectively. But cell-free extracellular ARGs (CF-eARGs) were significantly enriched with 1.8-logs in the electrolysis-intensified CW. Interestingly, adding Fe-C microelectrolysis to the electrolysis-intensified CW is conducive to the reduction of CF-eARGs. However, the detected number and relative abundances of intracellular and extracellular VFGs were increased in all of the three CWs. The biofilms attached onto the substrates and rhizosphere are also hotspots of both intracellular and particle-associated extracellular ARGs and VFGs. Structural equation models and correlation analysis indicated that ARGs and VFGs were significantly cooccurred, suggesting that VFGs may affect the dynamics of ARGs. The phenotypes of VFGs, such as biofilm, may act as protective matrix for ARGs, hindering the removal of resistance genes. Our results provide novel insights into the ecological remediation technologies to enhance the removal of ARGs. [Display omitted] •Electrolysis-intensified CWs can promote the removal of iARGs and iMGEs.•Electrolysis-intensified CWs coupled with Fe-C microelectrolysis can remove cell-free eARGs.•The diversity and relative abundances of VFGs in the CWs were increased.•Bioelectrochemical effects can shift the cooccurrence patterns of ARGs and VFGs in the CWs.•MGEs, VFGs and microbial community are the main factors affecting dissemination of ARGs in the CWs.