| The emergence and spread of antibiotic resistance is seriously threatening global public health and economic development.Since antibiotic resistance genes?ARGs?can be transferred in humans and the environment,they have been identified as a kind of new pollutants.ARGs have been widely detected in inland water environments at home and abroad.And the relative concentration of ARGs has a strong correlation with the corresponding antibiotic residues.The coastal marine environment has unique physical and chemical properties,and the concentration of antibiotic is far below that in the inland water environment.Therefore,the fate of ARGs may be different from that of inland water environment,and non-corresponding pollutants?non-antibiotics?may have important influence on the migration of ARGs.The study set Laizhou Bay and Dalian near-shore as typical offshore areas,and investigated the contents of typical antibiotic?sulfanilamide and quinolone?resistance genes in their environment,and analyzed the corresponding amounts of antibiotics and non-corresponding pollutants to reveal the level,distribution and composition of antibiotic resistance pollution in near-shore ocean environment,and the role of corresponding and non-corresponding pollutants in the transmission of ARGs.Based on the investigation and research,an experimental model of horizontal gene transfer?HGT?was established through laboratory simulations to explore the impact of comprehensive environmental factors on the process of HGT.The results of the study indicate that antibiotic-resistant pollution is widespread in the coastal marine environment,and sulfa-resistant genes have been widely detected in two coastal regions.The detection rate of sul1 and sul2 was 100%and the content was high,and the content showed a decreasing trend from the inner estuary to the coastal area.The relative abundances ranged from 1.08×10-31.36×10-1 copies/16S rRNA copies and 2.90×10-51.39×10-2 copies/16S rRNA copies,respectively in water and sediments.The distribution of sulfonamides and quinolones ARGs did not correlate with their corresponding antibiotic concentrations.There was a strong correlation between integron intlI and resistance genes,and some of the resistance genes were positively correlated with non-corresponding contaminants such as heavy metals.The results of horizontal transfer simulation experiments of resistant genes showed that the horizontal transfer of ARGs was affected by many factors,such as culture time,culture temperature and concentration of contaminants.Antibiotics had a strong ability to promote horizontal transfer.The probable reason is that antibiotics can make cells have a strong oxidative stress reaction,and the high concentration of antibiotics has especially a killing effect on the donor bacteria and the recipient bacteria,which has a promoting effect on the production of the zygote.In general,antibiotic resistant pollution in the coastal marine environment is widespread,and integrants and some non-corresponding pollutants play an important role in the progress of HGT.The main factor affecting the propagation of ARGs in the coastal marine environment may be changed from corresponding pollutants?antibiotics?to non-corresponding pollutants?heavy metals and organic pollutants?.Exploring the distribution characteristics and dissemination of ARGs in the coastal marine environment are important for preventing and controlling the spread of resistant pollution. |
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