| Various aromatic compounds in wastewater,especially industrial wastewater,are treated by biological processes in bioreactors which are regarded as hotspots and reservoirs of antibiotic resistance genes(ARG).Yet,little is known about the relationships between the aromatic compound degradation process and antibiotic resistance.To address this issue,we operated two bioreactors to treat simulated wastewater containing p-aminophenol(PAP)and p-nitrophenol(PNP)to study the association between the degradation of aromatic process and the ARG disseminate.Both PAP and PNP are important basic materials for production of pharmaceuticals,pesticides,and dyes,and are usually present at relatively high concentrations(> 100 mg/L)in industrial wastewater.We observed a significant enrichment of ARG in bioreactors treating wastewater that contained PAP and PNP and reported on the cooccurrence of ARG and aromatic degradation genes(ADG)in bacteria in bioreactors.Given the lack of systemic knowledge regarding genetic association between ARG and ADG,a comprehensive understanding is urgently needed.Furthermore,we expanded our analysis to investigate 71 metagenomes from different environments,and the results indicated that the impact of aromatics on ARG abundance widely occurs in various ecosystems and confirmed that high levels of aromatics could lead to a high abundance of ARG.(1)Three sequential batch bioreactors(SBR)(R0,R1,and R2)were operated to study the effect of aromatic compounds on bacterial ARG in wastewater treatment.Our results confirm that the PAP and PNP substances in wastewater promote ARG proliferation.Procrustes analysis and Mantel test analysis showed that aromatics mainly promoted the spread of ARG by shaping the microbial community structure in bioreactors.Network analysis shows that potential hosts with ARG and ADG are mainly Pseudomonas,Leucobacter,Xanthobacter,Acinetobacter,and Burkholderiaceae.Besides,we observed the co-occurrence of ARG and ADG on metagenome assembly genomes(MAG)extracted from the metagenomics.(2)Bioinformatics analysis of 10,243 complete bacterial genomes revealed that 67.6% of the bacteria carrying ADG also carried ARG.Among them,more than 80% of Burkholderiales,Xanthomonales,Enterobacteriaceae,Acinetobacter,Pseudomonas,and Nocardiaceae genomes carry both ARG and ADG.Furthermore,bacteria carrying ADG harbored more than twice the number of ARG than bacteria only carrying ARG.Network analysis showed that multidrug,?-lactam,aminoglycoside,macrolidelincosamide-streptomycin,and polymyxin resistance genes are the main ARG classes associated with ADG.In conclusion,we further understand the effects of genetic events on the formation of ARG and ADG in different genomic categories and provide strong evidence that ARG and ADG coexist on specific genomes,especially those that are basically related.In addition,we have expanded the scope of analysis and studied 71 metagenomic sequencing samples from different environments.The results show that the effect of aromatic hydrocarbons on ARG spread widely in various ecosystems,and confirmed that high levels of aromatic hydrocarbons may cause ARG High abundance.(3)We developed a practical method that uses ozone to pretreat PAP wastewater.We found that after the aromatic index(AI)in the wastewater decreases,it can very effectively reduce ARG abundance in the bioreactor.Compared with the control reactor,the relative abundance of ARG in the bioreactor pretreated with ozone was reduced by more than 70%.In addition,multidrug,quinolone,mupirocin,polymyxin,aminoglycoside,glycopeptide,beta-lactam,and trimethoprim resistance genes were all reduced in the bioreactors receiving wastewater pretreated by ozone... |
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