Molecular Epidemic Characteristics And Drug Resistance Analysis Of Carbapenem Resistant Enterobacteriaceae In Different Infection

Objectives To understand the molecular epidemiological characteristics,clinical prevention and clinical infection characteristics of carbapenems of Enterobacteriaceae in different infection routes in North China University of Science and Technology affiliated hospital,and provide evidence for effective control of transmission and clinical treatment.Methods The CRE strains infected by different routes of the North China University of Science and Technology Affiliated hospital were collected from June 2017 to December 2018 and trace clinical data of patients;Strains identification and drug sensitivity test using VITEK2-Compact automatic microbial analyzer,drug sensitivity test combined with paper diffusion method,E-Test method;Carbapenemase genes（KPC,NDM,IMP,VIM,OXA-48）,extended-spectrum β-lactamase genes（SHV,TEM,CTX,OXA-1）,Amp C enzyme genes（DHA,MOX,FOX）,pore protein genes（Omp K35,Omp K36）,quinolone resistance genes（qnr A,qnr B,qnr S,aac（6 ’）-Ib-cr,qep A）,aminoglycoside resistance genes（aac A4,rmt B,arm A,aph A6）and sulfonamide resistance gene（dhrf）were detected by PCR method to grasp the molecular characteristics of CRE in our hospital;The gene transferability of 141 carbapenemase-producing Enterobacteriaceae（CPE）strains was analyzed by plasmid conjugation test;The homology analysis of the strains used PFGE combined with MLST,and selected representative strains of different types according to the PFGE typing results to conduct MLST to understand the CRE molecular typing characteristics of different infection pathways.Results 1 Clinical data: 146 CRE strains isolated in North China University of Science and Technology Affiliated Hospital from June 2017 to December 2018 were mainly from the Department of Intensive care unit（46.58%）,and the top three strains were Klebsiella pneumoniae（117 strains）,Escherichia coli（19 strains）,Enterobacter cloacae（6 strains）,the strains are derived from respiratory specimens（53.42%）,blood（32.19%）,urine（8.9%）,Klebsiella pneumoniae is mainly concentrated in respiratory infections and bloodstream infections,the detection rate is greater than 80%,Escherichia coli Mainly concentrated in urinary tract infection strains（38.46%）.2 Genotyping: A total of 141 strains（96.57%）were positive for carbapenemase gene,with bla_KPC-2 the most（82.88%）,followed by bla_NDM-5（15.75%）.The positive rate of carbapenemase gene among different strains is greater than 80%.Carbapenemase-resistance Klebsiella pneumoniae（CRKP）mainly carries bla_KPC-2（91.23%）,carbapenemase-resistance Escherichia coli（CREC）mainly carries bla_NDM-5（89.47%）.The positive rate of carbapenemase gene in different infection routes was greater than 90%,bla_KPC-2 is the main genotype of respiratory tract infection strains（78.95%）and bloodstream infection strains（86.67%）.The positive rate of ESBLs gene（97.26%）was higher than the positive rate of Amp C enzyme gene（75.34%）,and the joint deletion of perforin gene was more serious（54.79%,34.25%）.In carbapenemase-producing Enterobacteriaceae（CPE）and non-carbapenemase-producing Enterobacteriaceae（NCPE）,NCPE’s ESBLs gene or Amp C enzyme gene combined with membrane pore protein gene deletions are both CPE is more severe.The urinary tract infection strains carried the ESBLs gene combined with the pore protein gene deletion rate was the highest（84.62%）.3 Results about resistance genes:Quinolone resistance genes were detected in all strains,bla_qnrB and bla_qnrS were mainly detected in Klebsiella pneumoniae（97.29%,80%）,and bla_qnrA was mainly detected in Enterobacter cloacae（57.14%）.The detection of aminoglycoside resistance genes in Escherichia coli is more severe（78.95%）.Among different infection systems,urinary tract infection strains are more likely to carry glucosinolate resistance genes（84.62%）,and sulfa resistance genes are positive low rate（6.85%）.4 Conjugation test: 10 strains（7.09%）of CRE were successfully transferred.The donor bacteria were mainly distributed in Klebsiella pneumoniae,Escherichia coli,Serratia marcescens and C.brucei.The splicing efficiency was 6.14%,5.26%,100% and 100%,of which bla_KPC success rate was 4.96%（6/121）,and bla_NDM success rate was 13.33%（4/30）.5 Homology analysis: 117 CRKP are divided into 46 PFGE classifications,of which 4 types contain more than or equal to 5 strains,namely PT08（40 strains）,PT10（5 strains）,PT34（5 9 strains）,PT37（7 strains）;19 CREC isolates a total of 9 PFGE types,the dominant type is ECPT03（10 strains）.The main strains of CRKP are mostly derived from respiratory specimens and blood.The dominant strains of CREC are widely sourced and can be detected in respiratory specimens,blood,urine,and cerebrospinal fluid,but both are mainly concentrated in ICU and NICU.MLST typing results show that 91 representative CRKP have 12 ST types,the main popular type is ST11 carrying bla_KPC-2（49 strains）,and found a new ST type（STNEW,allele spectrum is gap A1,inf B5,mdh1,pgi1,pho E1,rpo B1,ton B1）;8 representative CREC have 8 ST types,the main type is ST167 carrying bla_NDM-5.A new ST type was found（STECNEW,allele profile of adk9,fum C65,gyr B193,icd18,mdh11,pur A8,rec A6）.5 Conjugation test: 10 strains（7.09%）of CRE were successfully transferred.The donor bacteria were mainly distributed in Klebsiella pneumoniae,Escherichia coli,Serratia marcescens and C.brucei.The splicing efficiency was 6.14%,5.26%,100% and 100%,of which bla_KPC success rate was 4.96%（6/121）,and bla_NDM success rate was 13.33%（4/30）.6 Drug sensitivity results: CRE strains in our hospital are resistant to ampicillin,aztreonam,cefazolin,ceftazidime,and imipenem.The resistance rates to meropenem,levofloxacin,sulfamethoxazole,gentamicin,and amikacin were 98.63%,94.52%,46.57%,45.89%,43.15%,both tigecycline and polymyxin are sensitive.The resistance rate of strains of urinary tract infection to various common antibiotics is greater than 50%,and the resistance rate of Escherichia coli to various common antibiotics is greater than 70%.Conclusions 1 The drug resistance of CRE strains in the North China University of Science and Technology Affiliated Hospital is very severe.Among the different infection routes,the drug resistance of urinary tract infection strains is more serious.The strains were mainly isolated from respiratory specimens,blood and urine.The top three strains were Klebsiella pneumoniae,Escherichia coli and Enterobacter cloacae.2 The carbapenemase genes mainly carried by respiratory infection strains and bloodstream infection strains is bla_KPC-2,bla_NDM-5 is mainly concentrated in urinary infection strains;The positive rate of ESBLs gene,Amp C enzyme gene is higher,ESBLs or Amp C enzymes combined with deletion of membrane pore protein is the main mechanism of NCPE carbapenem resistance,and the most detected cases of ESBLs gene production and porin gene deletion in urinary tract infection strains in the North China University of Science and Technology Affiliated Hospital.3 CRKP and CREC have dominant types in the North China University of Science and Technology Affiliated Hospital.Different PFGE dominant types are distributed in different time periods and wards.CRKP popular clone group is ST11 type carrying bla_KPC-2,CREC popular clone group is ST167 type carrying bla_NDM-5,bla_NDM is easy to spread drug resistance through plasmid transfer.Figure15;Table16;Reference 208...