Antibiotic Resistance And Antibiotic Resistance Gene Transfer Of ESBLs-Producing Escherichia Coli In Naihe,Taian

Escherichia coli(E.coli),a kind of conditional pathogen,is widely distributed in nature,which can cause urinary tract infection and septicemia in human and animals.In clinic,?-lactamases are used as an important choice to treat bacterial infections.The overuse of ?-lactamases leads to the emergence of extended spectrum ?-lactamases(ESBLs)producing Escherichia coli,which has strong resistance and the resistance gene can be transmitted horizontally by plasmids.Therefore,the harm of ESBLs is worthy of attention.Water environment is an ideal environment for the acquisition,transmission and storage of antibiotic-resistant genes.Water is also the source of its pollution,carrier and the undertaker of antimicrobial abuse.Once human open wounds are infected by ESBLs strains produced in water through contact with water,it will lead to great difficulties in prevention and treatment.Therefore,its research significance cannot be underestimated.Urban river is the water environment and water quality of urban river running through the city and closely related to people's life,which is of great significance to the maintenance of urban public health and safety.Aim of this study was to investigate the prevalence and antibiotic resistance of ESBLs producing E.coli.From March to may 2018,272 river water samples were collected from the urban river in Tai'an area,and the ESBLs producing Escherichia coli was isolated and identified by drug screening medium culture,PCR amplification,double disk phenotype confirmation test;the specific serotype O157: H7 was detected by plate agglutination test.14 kinds of antibiotics commonly used by local people,doctors and veterinarians were selected and Kirby Bauer method was used to detect the drug-resistant phenotype.16 kinds of drugresistant genes and class I integron were detected by PCR technology.Enterobacterial repetitive intergenic consensu(Eric-PCR)and Multilocus sequence typing(MLST)were carried out by PCR to determine their typing and comparative analysis.Through the conjugation test,to explore the resistance of ESBLs producing E.coli.Eighty-eight strains of ESBLs producing Escherichia coli were identified in this study with the positive rate of 32.4%.Specific serotype O157: H7 was not found.The results showed that the multidrug resistance rate was 59.1%,all strains showed resistance to ampicillin,amoxicillin,cefthiophene,and resistance rate to imipenem was the lowest(1.1%).The resistance genes of blatem,qnrs,aacc2,AAC(6 ')-IB Cr,oqxa,oacc4 were detected,the positive rates were 94.3%,33.0%,29.5%,12.5%,11.4%,6.8% and 5.6%,respectively.About59.0% of the isolates carried two or more resistant genes,and 26.1% of the class I integron gene boxes contained seven different gene box structures.The highest positive rate of dfrA17-aadA5,dhfrA12-aadA2,dfr17-aadA5,dfrA12-aadA2 and aadA5 was 13.6%,3.4%,2.2% and1.1%,respectively.Forty-seven STs were detected in MLST,including 4 clonal complexes(CC).ST38 was the main sequence type,accounting for 13.6% of all strains,and two ST131 strains were found.Eighty-eight strains were divided into 51 genotypes by ERIC-PCR.The results of conjugation test showed that 83.0%(73 / 88),72.6%(53 / 73),4.1%(3 / 73),11.0%(8 / 73),12.3%(9 / 73)lost one or more resistant phenotypes and obtained one or more resistant phenotypes.After conjugation,the resistance spectrum of the conjugates to ampicillin,amoxicillin,and cefthiophene was still high,and the seven antibiotic resistance genes carried by the donor bacteria all had horizontal transmission.The gene transfer rates of blatem,oxa,qnrs,oqxa,aacc2,aacC4 and AAC(6 ')-IB Cr were 84.9%,100%,45.8%,62.5%,61.9%,33.3% and 62.5%,respectively.In this study,the prevalence of ESBLs producing E.coli in the middle class of Danhe River in Tai'an City was investigated for the first time,and the antibiotic resistance and gene transfer of ESBLs E.coli in the middle class of Danhe River were investigated.It has been found that multiple drug resistance of ESBLs in rivers is serious,and horizontal transmission can occur,which has a warning effect for citizens,has a guiding significance for regulating and limiting the use of antibiotics and clinical treatment of local bacterial infectious diseases,and has a reference significance for maintaining urban public health security.