Study On Risk Factors And Drug Resistance Mechanism Of Carbapenem-resistant Enterobacteriaceae Infection In Intensive Care Unit

Objective:To understand the drug resistance characteristics and risk factors of carbapenem resistant Enterobacteriaceae（CRE）infection among patients in the Intensive Care Unit（ICU）of a municipal tertiary hospital,and to elaborate the enzyme producing genotype and drug resistance mechanism of CRE strains,providing laboratory basis for clinical prevention and control of CRE nosocomial infection and drug treatment.Methods:A total of 78 patients with CRE infection who were treated in various ICUs of Ganzhou People’s Hospital from January 2019 to December 2021 were selected as the study group,and 82 patients without CRE infection who were treated in various ICUs during the same period were selected as the control group.A retrospective analysis was conducted on the distribution of CRE pathogens,drug resistance,demographic information of patients,antimicrobial drug use,laboratory related indicators,and other clinical data,The risk factors that may cause infection were analyzed by single factor and multivariate logistic regression analysis.The carbapenemase inhibitor enhancement test was used to detect the phenotypes of carbapenemases carried by CRE.Finally,Whole Genome Sequencing（WGS）was used to analyze the carrying status and ST type of CRE resistance genes.Results:（1）Logistic regression model showed that hypoalbuminemia,multiple use of antibiotics,endotracheal intubation,hospital stay>7 days,and cerebrovascular diseases may be independent risk factors for CRE infection in ICU patients,with a statistically significant difference（P<0.05）.（2） The main pathogens of 78 cases of CRE infection were Klebsiella pneumoniae（43.59%）and Escherichia coli（41.03%）;The main source of samples is sputum（91.03%）,followed by blood（3.85%）,urine（2.56%）,etc;Klebsiella pneumoniae and Escherichia coli are highly resistant to most commonly used antibacterial drugs,with a relatively low resistance rate to cefoperazone/sulbactam,tobramycin,and both are 100%sensitive to tigecycline.（3） Klebsiella pneumoniae mainly carries serine enzymes（28/34,82.35%）,while Escherichia coli mainly carries metal enzymes（26/32,81.25%）.A total of 13 positive genes were detected,of which 37 strains carried the bla _KPC-2gene,followed by bla _NDM-1,bla _TEM,bla _SHVand other drug resistance genes.Another 6 strains were detected to carry both the bla _KPC-2and bla _NDM-1genes.No strains carrying bla _VIM,bla _SPMand bla _IMPwere found.（4）The MLST typing results showed that ST11 was the main type,accounting for 79.37%.There were also ST15,ST17,ST71,ST35,ST37,ST40,ST45,ST290,ST299,ST3984-1LV and other ST types.Conclusion:ICU is a high-risk department for CRE infection,hypoalbuminemia,multiple use of antibiotics,invasive operation,long hospital stay and cerebrovascular disease can all increase the risk of CRE infection in ICU patients.ICU medical staff and hospital infection-control departments should attach great importance to such patients,and can carry out early CRE screening and early infection intervention sense and control measures to reduce the risk of hospital infection in patients with CRE.The important mechanism of CRE strains isolated in our hospital is the production of carbapenemases.Klebsiella pneumoniae and Escherichia coli mainly produce KPC-2and NDM-1 enzymes,respectively.The bla _KPC-2and bla _NDM-1genes are the main genotypes that mediate the resistance of CRE patients in our hospital’s ICU,mainly ST11 type.