Wastewater-associated plastispheres: A hidden habitat for microbial pathogens?

Area of Science:

• Environmental microbiology
• Public health
• Water quality

Background:

• Wastewater treatment plants (WWTPs) are sources of microplastics, which form biofilms called plastispheres.
• Plastispheres may harbor and spread human pathogens, creating health risks.
• The role of plastispheres in pathogen dissemination requires further investigation.

Purpose of the Study:

• To identify foodborne pathogens and characterize microbial communities within wastewater plastispheres.
• To assess the survival of pathogens on microplastics during wastewater treatment.
• To understand how wastewater environments and plastic types influence plastisphere composition.

Main Methods:

• Analysis of plastispheres on polypropylene, PVC, and HDPE in raw and treated wastewater.
• Utilized cultivation, quantitative reverse transcription PCR (RT‒qPCR), and 16S rRNA amplicon sequencing.
• Investigated bacterial and viral pathogens, alongside microbial community diversity.

Main Results:

• RT‒qPCR detected foodborne pathogens (Listeria monocytogenes, Escherichia coli, norovirus, adenovirus).
• Viable Klebsiella pneumoniae and Acinetobacter spp. were found in plastispheres from both raw and treated wastewater.
• Wastewater environment and exposure time significantly impacted plastisphere diversity and composition; plastic type had less influence.

Conclusions:

• Wastewater plastispheres can harbor and disseminate pathogenic microorganisms, challenging water reuse.
• Pathogenic bacteria may survive wastewater treatment within these biofilms.
• Improved microplastic removal and waste management are vital to mitigate public health risks from plastic-associated pathogens.