Profiles of antibiotic resistance genes and virulence genes and their temporal interactions in the membrane bioreactor and oxidation ditch

Antibiotic resistance genes (ARGs) and virulence genes (VGs) in wastewater treatment plants (WWTPs) may pose a potential threat to public health if without proper treatment. In this study, GeoChip was used to reveal the differences in ARG/VG diversity between a membrane bioreactor (MBR) and an oxidation ditch (OD) and the temporal co-occurrence patterns between ARGs and VGs. Results showed that the diversity of ARGs and VGs was lower in MBR than that in OD in the short term due to the better disinfection capability of MBR. However, the differences in diversity between two reactors disappeared in the long term because of the great variation of temperature. Instead, time-decay relationship was observed and overall turnover rate was −0.0105. Co-occurrence patterns indicate that direct connections between ARGs and VGs reduced sharply with time increasing due to the different responses of ARGs and VGs to environmental variation. •Antibiotic resistance and virulence gene profiles in MBR and OD are depicted.•The diversity of genes was lower in MBR than that in OD system in the short term.•Temperature was the driving factor for gene structures in the long term.•The variation of environment changed the occurrence patterns between genes.