REDTEAR · The Role of free Extracellular DNA in determining The Environmental Antibiotic Resistome

Free extracellular DNA (FED) is DNA dissolved in waters and in soils, where it arrives after being excreted by livingorganisms or following the disruption of living cells. FED can be the most prominent fraction of DNA in waters subjected tostrong disturbances, where the mortality rate of microorganisms is high, e.g. wastewater treatment plants effluents. FED arecomposed by a variety of DNA fragments including resistance genes and mobile elements. There are early evidences thanFED can represent a very important, although neglected, source of antibiotic resistance genes (ARGs) in the environment,where the bacterial community can access FED and incorporate extracellular DNA by horizontal gene transfer.If this process will be confirmed and quantified by dedicated researches, our understanding of the cycle of antibioticresistances into the environment and back to human pathogens could change dramatically, calling for a whole rethinking ofthe wastewater treatments nowadays applied. The Project REDTEAR will tackle the issue and will clarify the role of FED inthe spread and the persistence of ARGs in open waters in central Europe, offering a unique opportunity for a correctmanagement of this problem, already identified as one of the major challenges for human health in the next century.