Risk Factors,Drug Resistance Mechanism And Molecular Epidemiology Of ESBL-producing Klebsiella Pneumoniae Infection

Objective: 1.To retrospectively study the possible risk factors of ESBLs-producing Klebsiella pneumoniae infection.2.To study the possible resistance mechanism of ESBLs-producing Klebsiella pneumoniae.3.Molecular epidemiology of ESBLs-producing Klebsiella pneumoniae?Method: 1.Source of strains: KP isolated from patients in the First Affiliated Hospital of Nanchang University from June 2016 to December 2017 was collected.Only the first strains isolated from the same patient were retained.Strain identification and drug susceptibility test were automatically identified by VITEK-2 biological analyzer.High viscous phenotype was determined by drawing test and ESBL phenotype was confirmed by disc test.2.The data of patients with bacterial infection were collected by computer in-patient system.The medical records of ESBL-producing hv KP and non-ESBL-producing hv KP were collected according to the ratio of l:1.The patients' gender,age,blood sugar,basic diseases,use of antibiotics before infection,invasive operation and operation or major trauma were compared.The independent risk factors of ESBL-producing hv KP infection were analyzed according to the above data.3.Resistance mechanism: Polymerase chain reaction(PCR)was used to detect the distribution of bla TEM,bla SHV and bla CTX-M in ESBLs-producing strains.Plasmid conjugation transfer test was used to understand the transmission mode of drug resistance genes.4.Primers were designed by pulsed field gel electrophoresis(PFGE)typing and MLST typing.Polymerase chain reaction(PCR)and sequencing techniques were used to process and analyze PFGE images and MLST results using Bio Numerics software.Molecular epidemiology of ESBLs-producing Klebsiella pneumoniae.Results: 1.124 highly virulent Klebsiella pneumoniae strains were screened out from 1263 clinical isolates,of which 85 were positive for K1 capsular serotype and 39 were positive for K2 capsular serotype.Among 124 strains of highly virulent Klebsiella pneumoniae,45 were ESBL-positive hv KP strains and 79 were ESBL-negative hv KP strains.Overall,the proportion of patients infected by nonESBL-producing hv KP bacteria was higher than that infected by ESBL-produc-ing hv KP bacteria.2.Diabetes mellitus,invasive manipulation,use of carbapenems and quinolones,and hospitalization for more than 14 days were independent risk factors for ESBLs-Hv KP infection.3.Drug resistance gene detection showed that 22 strains carried bla TEM gene,13 strains carried bla SHV gene and 10 strains carried bla CTX-M gene.The resistance rates of ESBL-producing strains to ceftazidime,cefotaxime,cefoxitin,piperacillin/tazobactam,cefepime,ertapenem,imipenem,meropenem,levofloxacin,ciprofloxacin and ampicillin/sulbactam were significantly higher than those of nonESBL-producing strains.4.The results of MLST typing showed that there were 45 ESBL-producing hv KP strains,of which 28 were positive for K1 capsular serotype and 17 were positive for K2 capsular serotype.The positive strains of K1 capsular serotype were all ST23,while 10 of 17 K 2 ESBL-producing hv KP strains were ST65,5 ST86 and 2 ST14.The main ESBL-producing enzymes hv KP carrying ESBL gene were ST23 and ST65.Conclusion: 1.First of all,we should pay attention to whether diabetic patients are infected with ESBL-producing hv KP bacteria.Secondly,we should pay attention to the aseptic consciousness of invasive operations such as drainage,drainage time and rational use of carbapenems and quinolones.Reduce the length of hospital stay to reduce the chance of infection.2.The main types of ESBLs gene in Klebsiella pneumoniae with moderate and high virulence in Jiangxi are bla SHV-1,bla CTX-M-2 and bla TEM-1,which have serious drug resistance.3.ST23 and ST65 are the main types of ST.PFGE bands show a high degree of homology,suggesting that it is very important to strengthen the prevention measures of nosocomial infection and the control of transmission.