Degradation of plasmid-mediated resistance genes in poultry slaughterhouse wastewater employing a UV/H2O2 process: A metagenomic approach

Abstract

Poultry slaughterhouse effluents are important hotspots for the spread of both antibiotic-resistant bacteria (ARBs) and antibiotic resistance genes (ARGs), contributing to the antimicrobial resistance (AMR). This study reports a novel investigation to assess the effects of UV/H₂O₂ treatment on the removal of metaplasmidome-mediated ARGs from poultry slaughterhouse effluents. The effluent samples were subjected at 0.005–0.15 mol L⁻¹ of H₂O₂ and pH conditions (3, 5, 7 and 9). Bacterial community (rrs 16S rRNA), Escherichia coli (uidA) antimicrobial resistance (sul1 and int1) and metagenomic plasmid DNA removal were assessed. The UV/H₂O₂ treatment employing H₂O₂ = 0.01 mol L⁻¹ at pH 3 resulted in decreased of several markers (uidA, sul1 and int1). A metaplasmidome indicated the persistence of Burkholderiales order. The UV/H₂O₂ process reduced plasmid-associated ARGs by 92.5% and 90.4% at pH 3 and 7, respectively. Persistent genes were mainly composed of genes associated with efflux pumps and resistance to beta-lactams and fluoroquinolones. These findings contribute to mitigate the spread of AMR in the agricultural sector, especially through the implementation of more efficient treatments, and reducing the use of antibiotics in livestock farming.