Deciphering conjugative plasmid permissiveness dynamics in wastewater microbiomes

Wastewater treatment plants (WWTPs) are designed to robustly treat polluted water. They are characterized by ceaseless flows of organic, chemical and microbial matter, followed by treatment steps before environmental release. WWTPs are hotspots of horizontal gene transfer (HGT) between bacteria via conjugative plasmids, leading to dissemination of potentially hazardous genetic material such as antimicrobial resistance genes (AMRGs). While current focus is on the threat of AMRGs spreading and environmental maintenance, conjugative plasmid transfer dynamics within and between bacterial communities still remains largely uncharted. Furthermore, current in vitro methods used to assess conjugation in complex microbiomes do not include in situ behaviors of recipient cells, resulting in partial representation of transfers. We investigated the in vitro conjugation capacities of WWTP microbiomes from inlet sewage and outlet treated water using the broad host-range IncP-1 conjugative plasmid, pKJK...