Research About Plasmid-mediated Quinolone And ?-lactam Resistance In Aquatic Environment

The discovery and application of antibiotics has brought an unprecedented bright future to people's infection treatment,medical health,but the emergence of drug-resistant bacteria cast a shadow to this.scientists have developed different and updated antibacterial strategies,but bacteria coped it one by one.Since the first antibiotic penicillin discovered in 1929,the development of antibiotics has undergone enormous changes during less than a century's time,and antibiotic resistance is also appeared more and more serious in our lives.Quinolones and ?-lactam antibiotics as the main drugs in our usual anti-infective treatment,the current application has not only confined to the human body,animal husbandry,poultry breeding industry and fishery usage has far exceeded human itself.According to a statistics in 2013,China's daily antibiotics use of 1,000 people is 157 tons,which is 5.7 times to the United Kingdom(27.4 tons),5.5 times to the United States(28.8 tons),and in animals,China invested a total of 84240 tons antibiotics in 2013,200 times to the United Kingdom(420 tons)and 5.8 times to the United States(14,600 tons).In the other hand,nearly 80%of the antibiotics can't be completely degraded in the body,it was excreted as parent compounds or metabolites via urine or feces,which has brought great disaster to water environment,so the research of antibiotics and drug resistance is extremely urgent in the current situation.Plasmid-mediated resistance play a more and more important role in antibiotic resiatance study because of it's particular characteristics such as easy to spread,low level of resistance but can facilitate a high-level resistance.In recent years,plasmid-mediated quinolone resistance and ?-lactam resistance was studied more and more,but most of the studies are limited to the specific strains in order to research their drug resistance gene or other drug resistance characteristics,It can not evaluate the prevalence of drug resistance in the sewage environment from a macroscopic perspective.In this paper,we use the total genome of bacteria in wastewater as direct experimental material,detecting plasmid-mediated quinolone resistance gene qnrA,qnrB,qnrC,qnrD,qnrS,qepA,oqxA,oqxB and ?-lactam resistance gene blaTEM,blaCMY,blaCTX-M,blaDHA,blaSHV quantificationally in four sewage points in Jinan(Qilu Hospital,QL,Guangda Wastewater Treatment Plant,GD,Shandong Traditional Chinese Medicine Hospital,GD,Xiaoqing river,XQH),and analyse the microbial community structure in three months' sewage samples.The correlation between various types of bacteria and resistant genes was also been calculated.The results showed that the average copy number of 16S rDNA in SZY was 5.49×10~8 copies/mL,which was lower than that of QL,GD and XQH 4.70,7.44 and 15.77 times,respectively.The biomass in XQH is highest,followed by GD and QL.The content of drug resistance gene in the samples of QL was the highest,especially the content of aac-(6')-Ib-cr,oqxA,oqxB and blaCTX-M were far ahead of other sampling sites.Copy number of qnrB,qnrS and qnrD,qepA and blaCMY genes in the GD were higher than those of other sampling sites.The content of resistance genes was also high in XQH which is close to our daily life.Compared with different antimicrobial resistance genes,the aac-(6')-Ib-cr gene is the highest,at least 10 times higher than other resistant genes,the blaTEM gene content was highest in the?-lactamase genes.Through the analysis of the correlation of the antimicrobial resistance genes in each sampling point,it was found that the correlation between the ?-lactam resistance gene and the plasmid-mediated quinolone resistance in natural water bodies was obvious.When the sewage system undergoes different treatments artificial,the correlation between the two antimicrobial resistance genes is weakened,which is reflected in the results of the remaining three sewage sampling points.In the two different hospital sewage system,the correlation between the antimicrobial resistance genes shows consistent result,that is,the correlation among the PMQR genes is stronger,becomes weak between blaTEM and the PMQR gene,but there are still some other ?-lactam resistance genes and PMQR genes is inextricably linked.In GD,which was manual handed most severely,the link between the antimicrobial resistance genes is disorganized,and did not show a consistent regularity.The correlation between the resistance gene and the microbial community structure showed that there was a significant correlation between the bacteria and the antimicrobial resistance genes.Proteobacteria,Bacteroidetes,Actinobacteria,Verrucomicrobia,Cyanobacteria were found to be significantly associated with antimicrobial resistance genes,especially among Proteobacteria,Bacteroidetes,Actinobacteria,Verrucomicrobia,In the first two plylum,the ?,?,?,?-Proteobacteria and Bacteroidia,Flavobacteria,Sphingobacteriia have a significant correlation to antimicrobial resistance genes,not only in the plylum level,but also class,order,family and genus.The bacteria associated with ?-lactam resistance genes are ?,?,?-Proteobacteria,Aeromonas in y-Proteobacteria and Rheinheimera.The bacteria linked to plasmid-mediated quinolone resistance gene qnr are:?,?-Proteobacteria,Frankiales and Bacteroidetes.Bacteria that have a significant correlation with the efflux pump genes are:Xanthomonadaceae and Frankiales.