| Objective:To analyze carbapenem resistant Enterobacteriaceae(CRE)isolated from infection and colonization samples of clinical patients in the Second Clinical Medical College of Yangtze University,results of antibiotic sensitivity test of CRE strains commonly used clinical antibiotics and provide theoretical data for clinical effective treatment plan;To make statistics on the basic clinical characteristics of CRE inpatients and remind clinical monitoring and active prevention and control of susceptible population and key departments;To explore the carbapenemase production of CRE strains in infection and intestinal colonization in our hospital the main types and other drug-resistant molecular types provide scientific basis for effective control of CRE in hospital transmission and reasonable clinical treatment.Methods:156 CRE strains were collected from the clinical samples from May 2017 to May 2019 in the Microbiology Department of the Second Clinical Medical College of Yangtze University.65 CRE strains were isolated from rectal swabs,91 non rectal swabs from other infected sites,and the same strains from the same patient in the same site were removed.The distribution,Department source and sample source of all drug-resistant strains were analyzed by Excel.VITEK 2 compact automatic microbial analysis system and matrix assisted laser desorption ionization time of flight mass spectrometer(MALDI-TOF MS)were used for bacterial identification.The sensitivity of commonly used antibiotics were tested by drug sensitive card.Common carbapenem genes were detected by PCR,including blaKPC,blaNDM,blaIMP,blaVIM,blaOXA-48,extended spectrum ?-lactamases gene,(ESBLs),including blaTEM,blaSHV,blaCTX-m;Colistin resistance gene mcr-1;Membrane porin gene,including OmpK35,OmpK36;Detection of virulence gene of Klebsiella pneumoniae resistant to carbapenem,including magA,wcaG,rmpA.Multi focus sequence typing(MLST)was used to analyze the molecular epidemiology of Klebsiella pneumoniae,Escherichia coli and Enterobacter cloacae.Results:(1)156 CRE strains,including 65 CRE colonization strains and 91 CRE infection strains,and E.coli,Klebsiella pneumoniae and Enterobacter cloacae were common.The detection rate of Escherichia coli was the highest in CRE colonization and Klebsiella pneumoniae was the highest in CRE infection.Among the CRE infection strains,the top three were 27 strains in ICU,accounting for 29.7%(27/91);15 strains in pediatrics,accounting for 16.5%(15/91);11 strains in urology,accounting for 12.1%(11/91),and the infection strains were more widely distributed than CRE colonization departments,most of which were CRE strains in ICU,40 strains were isolated from sputum,accounting for 44.1%(40/91);17 strains were isolated from urine,accounting for 18.7%(17/91);10 strains were cultured in blood,accounting for 11.1%(10/91).(2)The results showed that the resistance rate of CRE to Cefazolin,Cefoxitin,Ceftriaxone,Ampicillin,Imipenem,Ertapenem,Amoxicillin Clavulanic acid was more than 90%,only to Amikacin and Tegacyclin was lower.The resistance rates of CRE colonized strains to Cefepime,Amikacin,compound Minophen,Furantoin and Piperacillin Tazobactam were higher than those of CRE infected strains.Except Amikacin and Furantoin,the resistance rates of the other three strains were higher than 90%.(3)The sensitivity and specificity of mCIM were 97.1%and 100%respectively.Among the 65 CRE colonized strains,50.8%of the strains produced carbapenem,3.1%of them carried two carbapenem enzymes,which were carried by carbapenem resistant Escherichia coli.NDM was the main carbapenem enzyme in Escherichia coli,The detection rate was 17.5%,KPC was 16.4%,VIM was 5.4%,and OXA-48 was 1.0%.The major carbapenemase genes of CRE colonization and CRE infection were NDM.Klebsiella pneumoniae producing KPC and OXA-48 were mainly isolated from clinical infection samples rather than rectal swab screening samples.The isolation rate of IMP was higher in CRE infection patients.(4)Among 65 strains of CRE,the detection rate of TEM gene was 98.4%(64/65),SHV gene was 30.7%(20/65),CTX-m gene was 61.5%(40/65).Among 91 strains of CRE,the detection rate of TEM gene was 98.9%(90/91),SHV gene was 54.9%(50/91),CTX-m gene was 36.2%(33/91).These three ESBLs genes were detected in Klebsiella pneumoniae,Escherichia coli,Enterobacter cloacae and Citrobacter Freund.(5)Among 65 CRE colonized strains,the deletion rate of OmpK35 gene was 24.6%(16/65),OmpK36 gene was 69.2%(45/65),Enterobacter cloacae,Citrobacter freundii and Enterobacter Kobe membrane porin gene was completely absent;Among 91 CRE infected strains,the deletion rate of OmpK35 gene was 34.0%(31/91),the deletion rate of OmpK36 gene was 51.6%(47/91),Morganella morgensis and Proteus mirabilis No membrane porin gene was detected in the bacteria.The deletion rate of OmpK35 gene in Klebsiella pneumoniae was higher than that of OmpK36 gene.Only OmpK35 gene was detected in Escherichia coli,and the deletion rate of OmpK36 gene was 100%.(6)Only three strains of Klebsiella pneumoniae had virulence gene,the detection rate of wcaG was 1.7%(1/59),the detection rate of rmpA was 3.4%(2/59),one strain was from CRE colonization,the other strain was from CRE infection;no magA virulence gene was detected.(7)All CRE strains were negative for Colistin resistance gene mcr-1(8)There are 8 ST types in CRE infected strains,including 17 ST11(40.4%),7 ST37(16.6%),3 ST147(7.1%),2 ST20(4.7%),1 ST234(2.3%),1 ST668(2.3%),1 ST721(2.3%),and 1 ST876(2.3%).There are 8 ST types in CREC There are 8 ST167(34.7%),4 ST38(17.3%),2 ST10(8.6%),2 ST131(8.6%),1 ST2003(4.3%),1 ST410(4.3%),1 ST617(4.3%),1 ST69(4.3%);6 ST418(40.0%),5 ST93(33.3%),1 ST74(6.6%),1 ST175(6.6%),1 ST592(6.6%),1 ST88(6.6%).Conclusion:(1)The strains of CRE infection or colonization were mainly found in Klebsiella pneumoniae,Escherichia coli and Enterobacter cloacae.The infection samples were mainly isolated from respiratory tract and urinary system infection samples,the most common in intensive care unit,followed by pediatrics and urology.Strict patient isolation and environmental disinfection system was implemented in high-risk departments.(2)The common antibiotics showed multiple resistance.The sensitivity to tegacyclin and amikacin was high.The infection control department should attach great importance to the management of antibiotic classification.(3)The common carbapenemases in our hospital were detected.In CRE colonization or infection strains,blaNDM had the highest detection rate,followed by blaIMP and blaKPC,TEM gene was the most common in ESBLs gene,and OmpK36 deletion rate was higher than OmpK35 in membrane porin deletion.CRE strains combined with multiple drug resistance genes at the same time,resulting in complex and diverse drug resistance mechanism.(4)The dominant ST type of CRKP is ST11 with KPC enzyme,and the dominant ST type of CREC is ST37 with NDM enzyme;the dominant ST type of CREC is ST167 with NDM enzyme;the dominant ST type of CRECL is ST418 with NDM enzyme,followed by ST93 with IMP enzyme.There are many molecular types of resistant strains,and there are clonal diversity transmission.The mechanism of CRE resistance is complex and diverse,which makes it highly resistant to a variety of antibiotics,making it difficult to treat clinical infection.The infection control department of hospital must pay attention to and strengthen the monitoring of CRE strains,and actively take effective prevention and control measures. |
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