Metagenomic insights into the wastewater resistome before and after purification at large‑scale wastewater treatment plants in the Moscow city

A study in Moscow, Russia, found that wastewater treatment plants (WWTPs) are hotspots for the spread of antibiotic resistance genes (ARGs). The study analyzed raw wastewater, activated sludge, and treated wastewater from two large WWTPs. The results showed that several hundred ARGs could confer resistance to commonly used antibiotics in untreated wastewater. The resistome, which constituted about 0.05% of the metagenome, decreased by 3-4 times after water treatment. The removal efficiency of particular ARGs was impacted by treatment technology. The study suggests that the abundance and content of ARGs depend on social, economic, medical, and environmental factors.