Analysis Of Clinical Characteristics And Antibacterial Resistance Mechanisms Of Carbapenem-resistant Klebsiella Pneumoniae

Objective: To study the carbapenem-resistant Klebsiella pneumoniae of clinical distribution,risk factors,antibacterial resistance mechanisms and homology in the hospital and provides effective scientific guidance for the rational use of antibacterial and nosocomial infection monitoring.Methods: The CRKP strains were isolated from clinical samples from January 2015 to December 2016 were collected.The number of replicates was removed.The routine drug susceptibility test(instrument method)was performed by using the Mérieux VITEK2 Compact identification drug sensitivity system and its supporting reagents.The drug susceptibility results of carbapenem antibiotics were checked by Kieby-Bauer method(KB method)or concentration gradient diffusion method(E-test method);retrospective analysis of CRKP-infected patients was conducted by case-control method through analyzing risk factors and clinical outcomes;Carbapenemase assays were performed by using Modified Carbapenem Inactivation Method(mCIM)and metalloenzymes were assayed using ethylenediaminetetraacetic acid(EDTA)synergy assays.Carbapenemase-resistant genes(KPC,IMP,VIM,NDM-1,OXA-48,etc.)were detected by polymerase chain reaction(PCR),following PCR sequencing in amplification positive products,that can determine their genotypes;genetic homology of the KPC strains was conducted by the E.coli genome repeat consensus sequencing.The ERIC-PCR is used to explore the molecular epidemiological characteristics.Results: A total of 50 cases of CRKP were isolated from January 2015 to December 2016.Among the CRKP-infected specimens,the proportion of respiratory specimens was the highest,with 27 cases(54%),following by urine samples with 13 cases(26%);The distribution of clinical departments was mainly in the Intensive Care Units,with 23 cases(46%).We analyzed the drug-sensitivity data showed that CRKP showed high levels of resistance to most commonly used antibiotics,which including against carbapenems,beta-lactamase inhibitors,cephalosporins and aztreonam.The drug resistance rate exceeds 80%.Patients with CRKP infection have multiple risk factors.Multivariate Logistic regression analysis showed that the course of cephalosporin antibiotics treatment(OR=7.679,95%CI:1.226-48.089,P<0.05)was the independent factor of patients with CRKP infection.The clinical mortality rate of CRKP infection was 18%.Among 50 CRKPs isolated samples,thirty-seven had positive mCIM test results and 3 had EDTA positive tests.The PCR results showed that among the 37 CRKP positive mCIM assays,thirty-three KPC-2 resistant genes were detected and no resistance genes such as IMP,VIM,NDM-1,and OXA-48 were detected.ERIC-PCR classified KPC type CRKP into five genotypes,the most frequently one was type I genotypes that with 19 strains,Most cases were distributing from Intensive Care Unit.Conclusion: CRKP is mainly isolated from respiratory tract specimens and urine specimens.The positive cases were mainly isolated from Intensive Care Unit.The application of cephalosporin antibiotics is an independent risk factor for CRKP.In the development of anti-infective treatment programs,clinical conditions should be comprehensively analyzed.According to the risk factors of infection,it should be taken into consideration,such as combination treatment with the drug sensitivity results.The mechanism of CRKP resistance is complex,which mainly includes carbapenemase and KPC-2 strains.They are often detected in clinical practice,meanwhile,the spread of CRKP clones is also presenting in critical care units.Therefore,we should reasonably regulate the application of antibacterial drugs in clinical treatment.Collaboration with hospital infection management departments to strictly monitoring and preventing multi-drug resistant bacteria is needed,which can avoid the prevalence and outbreak of CRKP.