Fibrous and Fragmented Microplastics Discharged from Sewage Amplify Health Risks Associated with Antibiotic...

Area of Science:

• Environmental Science
• Microbiology
• Environmental Chemistry

Background:

• Wastewater treatment plants (WWTPs) are significant sources of antibiotic resistance genes (ARGs) and microplastics (MPs) in aquatic ecosystems.
• Limited field data exists on the copollution of ARGs and MPs, impeding comprehensive environmental risk assessments.

Purpose of the Study:

• To investigate the composition and association of ARGs and MPs in waters receiving sewage discharge.
• To determine the role of WWTPs in shaping the aquatic resistome through microplastic interactions.

Main Methods:

• Metagenomic sequencing and high-throughput quantitative PCR (qPCR) were employed to analyze ARG and MP profiles.
• Statistical modeling, including projection pursuit regression, was used to assess MP-associated risks.

Main Results:

• Sewage discharge significantly increased ARG-MP complexes in receiving waters, with fibrous and fragmented MPs showing enhanced ARG enrichment.
• Microplastics facilitated plasmid-mediated gene transfer and intracellular ARG proliferation within the plastisphere.
• Strong co-occurrence patterns were observed between MPs (especially fibrous and fragmented) and ARGs, virulence factors, and mobile genetic elements.

Conclusions:

• WWTP effluents contribute to ARG-MP complex formation, with MPs acting as vectors for ARG dissemination and pathogen selection.
• Fibrous and fragmented microplastics, particularly polyamide types, are associated with increased environmental risk in downstream areas.
• Microplastics provide a protective niche for extracellular ARGs, promoting their proliferation and contributing to the aquatic resistome.