Detection And Homology Analysis Of Drug Resistance Genes Of Klebsiella Pneumoniae In Bloodstream Infection

Objective:To understand the clinical distribution characteristics of MRKP isolated from whole blood specimens of the First Affiliated Hospital of Bengbu Medical College and their resistance to commonly used antibacterials;to analyze the β-lactamase andβ-lactamase resistance carried by Klebsiella pneumoniae Drug genotypes;exploring the homology of Klebsiella pneumoniae in whole blood samples to study its molecular epidemiological characteristics;providing a reference basis for the rational use of antibacterial drugs in clinical practice and reducing the spread of drug-resistant strains.Methods:1.Collect non-repeatedly isolated MRKP from clinical whole blood specimens from the First Affiliated Hospital of Bengbu Medical College from January 2017 to February 2019.The strains were identified and compounded by matrix-assisted laser desorption ionization time-of-flight mass spectrometer(MALDI-TOF-MS).2.Using Vitek-2 Compact full-automatic microbial drug sensitivity analyzer and its supporting drug sensitivity card to detect the sensitivity of Klebsiella pneumoniae to commonly used antibacterial drugs.Screening of β-lactamase-producing strains according to the Drug Sensitive Paper Diffusion Method(KB method)recommended by the American Society of Clinical Laboratory Standards(CLSI): Paper confirmatory test to detect ESBLs,Cefoxitin three-dimensional confirmatory test to detect AmpC enzyme,carbocyanine Mycelene antibacterial drugs inactivation tests(mCIM method and eCIM method)detect carbapenemase.Polymerase chain reaction(PCR)technology was used to detect β-lactamase resistance genes.3.The molecular epidemiological analysis(ERIC-PCR)of strains of Enterobacteriaceae bacterial gene repeats(ERIC)was performed by means of polymerase chain reaction(PCR)technology.Results:1.A total of 155 strains of Klebsiella pneumoniae were collected from clinical blood samples.After screening,93 strains of MRKP were obtained.The maindepartments were distributed in the intensive care unit(ICU),emergency department and other departments.2.Drug susceptibility results show that the resistance rate to cephalosporins was higher than 74.19%;the resistance rate to imipenem was 67.74%;the resistance rate to aztreonam was 81.72%;and to other quinolone and amino groups The resistance rates of glycosides and other drugs were higher than 65%.3.Enzyme-producing test results showed: 24 ESBLs-positive strains were detected by a paper-based confirmation test;36 AmpC-positive strains were detected by a three-dimensional test;65 carbapenemase-positive strains were detected by an mCIM test According to the eCIM test,11 strains of metal carbapenemase-positive strains were detected;only 11 strains were produced by all three enzymes.4.Enzyme-producing gene analysis results: Class A β-lactamase detected 63 strains of KPC gene,70 strains of SHV gene,66 strains of TEM gene,11 strains of CTX-M gene,and neither GES nor VEB gene was detected;B 16 strains of IMP gene were detected with metalloid β-lactamase,but no VIM and NDM-1 genes were detected;20strains of DHA gene were detected with C-type β-lactamase,namely AmpC enzyme,and no FOX and ACC were detected Gene;class D β-lactamase containing OXA-48 gene was not detected.37 strains containing three different drug-resistant genes were detected,and 11 strains of four and five different drug-resistant genes were detected.5.The positive products were confirmed by NCBI gene library query and BLAST comparison: KPC-type amplification products belong to KPC-2 type,and have the highest similarity and homology to E.coli-derived strains(SEQ ID: MH411118.1).It was 100%;SHV type amplification products could be identified as SHV-11 type,which had the highest similarity to Klebsiella pneumoniae strain(serial number: MH733892.1)and was 100% homologous;TEM type amplification products could Determined as TEM-1 type,it had the highest similarity with E.coli-derived strain(sequence number:MK405592.1),with 100% homology;DHA type amplification products could be confirmed as DHA-1 type,The Salmonella enterica strain(serial number: NG-049055.1)had the highest similarity with 100% homology.6.ERIC-PCR analysis showed that there were clones among 93 MRKP strains,which could be divided into 12 types(represented by A ~ K,B1),including 48 strains of type B,16 strains of type F,and type I.8 strains,4 strains of D type,3 strains of A type,and 2 strains of other types,mainly occurred in ICU(23 strains),emergency medical department(14 strains)and emergency surgery(7 strains).Conclusions:1.93 strains of MRKP were mainly distributed in ICU,emergency medical departments and other departments.Attention should be paid to strengthening infection control in related departments to prevent the outbreak of nosocomial infections.2.The drug resistance of 2.93 strains of MRKP was more serious,and the detected drug resistance genotypes carried two or more β-lactamase resistance genes.The combination of KPC + SHV + TEM was the most common,suggesting that these bacterial infections were serious Under the circumstances,the available antibiotics were limited,and clinicians should pay great attention to them.3.There were clonal disseminated strains among 3.93 strains of MRKP,among which type B was the dominant clone strain.Relevant departments and departments should attach great importance to strengthen infection control in our hospital and reduce the number of referral treatments between unnecessary departments.