The application of the photo-electro-Fenton process in the treatment of wastewater reduces the abundance of genes associated with pathogenicity factors, antibiotic resistance, and metabolism: A metagenomic analysis

The objective of this work was to determine the effect of advanced oxidation systems on the taxonomic and functional diversity of pathogenic microorganisms in the effluent of the wastewater treatment plant in Bogota - Colombia ("El Salitre" WWTP) by metagenomics analysis. The taxonomic and functional diversity of the microorganisms, before and after oxidation treatment, was determined by Illumina mass sequencing, detecting human pathogenic genera as Pseudomonas (28.0%), Arcobacter (10.0%), Aeromonas (4.0%), Sulfurospirillum (4.0%), Salmonella (3.0%), and Clostridiales (3.0%). Likewise, pathogenicity factors such as antimicrobial resistance genes (ARGs) also were detected in high abundances (similar to 5% of metagenome reads). In the effluent treated with the photoelectro-Fenton system (for 5, 30, and 60 min), a significant reduction of pathogenicity factors was observed in all cases. ARGs, chemotaxis, quorum sensing, secretion systems, and toxins of pathogenic bacteria (such as Arcobacter, Pseudomonas, Serratia, and Salmonella) were reduced at near-zero log(2) values, demonstrating that the photoelectro-Fenton process is a promising alternative to reduce the biological risk associated with this pathogenicity factors.