Oxidative stress enhances integrase activity during wastewater treatment

We analyzed the prevalence of bacterial resistance to inhibitors of folate biosynthesis in treatment wetlands, a nature-based technology often used for decentralised wastewater treatment. Over a four-year period, we compared an aerated and a non-aerated horizontal subsurface flow wetland receiving the same pre-treated municipal wastewater. We found that while aeration lowers AR gene abundances in the effluent, it also resulted in a transient increase of class 1 integrons copy numbers and integrase activity.