The dissimilarity of antibiotic and quorum sensing inhibitor on activated sludge nitrification system: Microbial communities and antibiotic resistance genes

Effects of antibiotics (azithromycin, AZM, 1-40 mg/L) and quorum sensing inhibitor (QSI, 2(5H)-furanone, mg/L) combined pollution with environmental concentration of copper on bacterial/archaeal community antibiotic resistance genes (ARGs) in activated sludge system were explored. QSI inhibited nitrification obviously than AZM. AZM and QSI were synergistic inhibitions on bacterial diversity, and AZM inhibited terial compositions more than QSI. While, QSI had more impacts on archaeal diversity/compositions. Less teractions among bacteria and archaea communities with Aquimonas as keystone genus. Functional differences bacteria/archaea communities were little, and AZM had more effects on metabolism. AZM mainly affected trifying bacteria (Candidatus Nitrospira nitrificans and Nitrosomonas). Specific denitrifying bacteria were enriched by AZM (Brevundimonas, 1.76-31.69%) and QSI (Comamonas, 0.61-9.61%), respectively. AZM enriched more easily than QSI and they were antagonistic to proliferation of ARGs. Bacteria were main hosts of (macrolide-lincosamide-streptogramin B, other/efflux, etc.) and archaea (Methanosphaerula, Methanolobus) ried multiple ARGs.

Automated summary

This study investigated the effects of antibiotics and quorum sensing inhibitor combined pollution with copper on bacterial/archaeal community antibiotic resistance genes (ARGs) in activated sludge system. The results showed that antibiotics and quorum sensing inhibitor had different inhibitory effects on microbial diversity and composition, as well as metabolism. Furthermore, specific denitrifying bacteria were enriched under the influence of antibiotics and quorum sensing inhibitor, but they had antagonistic effects on the proliferation of ARGs.