Distribution Of Antibiotic Resistance Genes In Different Types Of Water Bodies And Their Influencing Factors

In this study,tetracyclines(tet A),sulfonamides(sul1,sul2),aminoglycosides(aad A-1),macrolide(erm B)antibiotic resistance genes(ARGs)and class 1 integron(int I)gene the types,abundance and microbial community structure of ARGs in different ecological niches in different seasons were examined by fluorescence quantitative PCR and high-throughput sequencing techniques,respectively,and the relationships between ARGs abundance,microbial community structure and environmental factors were analyzed.The key factors affecting the distribution of ARGs in different water bodies were revealed,which provided basic data and technical references for controlling the pollution of ARGs in water bodies and ensuring the safety of environmental water quality.The specific findings of the study are as follows:(1)Five ARGs and Class 1 integron gene were detected in the three polluted river sections and surface flow wetlands,but erm B was not detected in the water source reservoir;the overall abundance trend of ARGs in the monitoring area was: water source reservoir <artificial wetland < polluted river section;the abundance of ARGs in the sediment of the same sampling site was 2-3 orders of magnitude higher than that of the water body,indicating that ARGs were more likely to be enriched in the sediment.(2)High-throughput sequencing results showed that Proteobacteria,Firmicutes,Actinobacteriota,Chloroflexi,Cyanobacteria and Bacteroidota were the dominant phylum in the polluted river section,artificial wetland and water source reservoir.Combined with physicochemical parameters and ARGs abundance analysis in the receiving river section and artificial wetland simultaneously found that: GKS98＿freshwater＿group correlated significantly with sul1,tet A and class 1 integrons gene;Romboutsia correlated significantly with erm B;Limnohabitans correlated significantly with tet A and aad A-1;total nitrogen and The correlation between total nitrogen and ammonia nitrogen and class 1 integrons gene was significant and negative.In the water source reservoirs,most genera were highly correlated with tet A,sul1,sul2,aad A-1 resistance genes,and more groups were correlated with tet A,GKS98＿freshwater＿group was the main factor affecting tet A,only a few genera showed correlation with water quality conventional indexes,such as Limnohabitans genera and ammonia nitrogen was significantly negatively correlated.The microbial community structure in the water body downstream of the wastewater treatment plant outlet is relatively more evenly distributed than upstream,and it is presumed that the effluent of the wastewater treatment plant has the role of regulating the microbial community structure in the river.(3)In the artificial wetland,the five ARGs were totally reduced by 67.86% in spring,38.13% in summer and 33.27% in autumn in general,and the wetland had almost no degradation effect on ARGs in winter.