Figure 2.

Presence of ARGs in microbial families in the two wastewater purification plants. The phylogenetic tree was constructed from family-level OTUs based on 16S rRNA gene amplicon sequences. An ARG was considered to be present in a bacterial genus when found in 2/2 or 3/3 samples (depending on whether all three samples passed the QC step) from the influent or effluent water at the same plant. The inner circle (INF) denotes the influent and the outer circle (EFF) the effluent water. The results are presented at family level and bars in the INF and EFF rings display relative abundance.