Occurance,Composition Characteristics And Resistance Mechanisms Of Antibiotic Resistant Bacteria In Fields Peninsula,Antarctica

In recent years,antibiotic resistance in the environment has been a global concern.However,there are very few studies on the distribution characteristics and drug resistance mechanisms of antibiotic resistance bacteria(ARB)in the sub-Antarctica,which is essential for assessing the level of pollution and assessing the "baseline" or background level of ARB in human uninhabited environments.In order to solve this problems,The Fildes Peninsula of Sub-Antarctica was selected as a typical representative area of Sub-Antarctica in this study,analyzed the resistance level of ARB in soil and sediment,and mastered the distribution characteristics of ARB;Some different traits of ARB which was constant temperature shaker cultured were Species identification to further reveal the compositional characteristics of the ARB in the Fildes Peninsula of Sub-Antarctica.The abundance levels of 295 antibiotic resistance genes(ARGs)and 16 S r RNA in ARB of different species were detected to explore the composition characteristics and drug resistance mechanism of ARGs in Antarctic strains.The results show that:(1)Sulfamethazine and ciprofloxacin-resistant bacteria are widespread in the Fildes Peninsula of Sub-Antarctica.Ciprofloxacin-resistant bacteria were detected in lakes,marine sediments,and soil,while sulfamethazine-resistant bacteria were not detected in most marine sediments.The highest abundances of ciprofloxacin and Sulfamethazine-resistant bacteria were 52 CFU/g and 80 CFU/g,respectively.Compared with the low-latitude regions affected by human activities,the pollution level of ARB was lower.At the same time,the ARB abundance level of the Fildes Peninsula in Sub-Antarctica is affected by human activities and animal migration by comparingthe resistance rates of resistant bacteria at different sites(2)It is concluded that most of the ARB in the Fildes Peninsula of Sub-Antarctica belong to the Proteobacteria by constructing a phylogenetic tree.Specially,Pseudomonas bacteria show a very obvious advantage in sulfamethazine-resistant bacteria.(3)295 ARGs were analyzed by using Real-time quantitative PCR technology among 17 different species of ARB.The results showed that 106 ARGs were detected in ones,including sul A,fol P-03,acr A-04,str B,qac Edelta1-01,pik R2,va C-03,qac H-01,mex F,cml A1-01,acr A-05,tet(34),which the detection rate of(the number of strains detected accounts for the total number of strains)is more than 50%.Through comparing antibiotic resistance of ARB and corresponding ARGs,it was found that all sulfamethazine-resistant bacteria contained sulfonamide ARGs and some ciprofloxacin-resistant bacteria contained quinolone ARGs.(4)ARB has five drug resistance mechanisms: a.antibiotic deactive;b.integrase;c.Cellular protection;d.efflux pump;e.transposase.In order to explore the role of genetic elements in the transmission of antibiotic resistance genes in polar bacteria,correlation analysis of antibiotic resistance genes and genetic elements was analyzed,founding that there is a strong positive correlation between int I-1(clinic)and Pik R2 and there is a strong positive correlation between tnp A-05,tnp A-02 and sul A,fol P-03,str B,qac Edelta1-01,and cml A1-01.It is indicated the rule of genetic elements spreading microbial antibiotic resistance are also applicable to the sub-Antarctica environment.