Strategies and Barriers to avoid the spread of Antibiotic Resistance genes during Wastewater Treatment.

SandBAR is the first comprehensive initiative to investigate how wastewater treatment plants (WWTP) affect the transfer and occurrence of antimicrobial resistance (AMR) to and in human pathogens.

Background and aim
Increased AMR in human pathogens is an acute public health threat. Human pathogens resistant to methicillin, fluoroquinolones, penicillin or third-generation cephalosporins are already major threats to human health. A profound example is the emergence of so-called extended spectrum β-lactamase (ESBL) pathogens and carbapenem resistant enterobacteria (CREs): their resistance to all β-lactam antibiotics (pencillins, cephalosporins, carbapenems) can make a CRE infection fatal.
This rapid spread of antimicrobial resistance genes (ARGs) is in large part due to the fact that ARGs are often located on mobile genetic elements (MGEs) such as plasmids, which can be rapidly disseminated between microorganisms via horizontal gene transfer (HGT). Hence, systems that host high microbial abundance and receive significant influent og AMR organisms likely promote transfer of ARG plasmids. WWTPs are one such hotspot and as traditional WWTPs are not designed for removal of ARGs; they may actually promote HGT.

In SandBAR we will examine how plasmids and genes encoding AMR spread, persist or are eliminated from WWTPs and how this effects their occurrence in pathogens. We will identify traits of the WWTP microbial communities that promote HGT and the spread of ARGs. SandBAR will reveal relevant microbial groups and MGEs that facilitate spread of antibiotic resistance traits from and to human pathogens and we will identify WWTP conditions and configurations that serve as barriers for transfer.

WWTPs are crucial for the fate of Antimicribial Resistance genes (ARGs) especially as urban water usage is becoming ever more circular and the gab between wastewater treatment and potable water production is shrinking, with efforts targeting reuse. Considering the acute global public-health threat posed by AMR, the obvious load of human waste-born AMR to the sewer systems, and the increase in wastewater reuse this study is a critical step in evaluating the potential burden or mitigation opportunities of the wastewater treatment towards AMR dissemination.