Domestic wastewater is a significant reservoir of antibiotic resistance genes, which pose environmental and public health risks. We aimed to define an antibiotic resistome signature, represented by core genes, i.e., shared by ≥ 90% of the metagenomes of each of three conceptual environmental compartments – wastewater (influent, sludge, effluent), freshwater, and agricultural soil. The definition of resistome si...