Risk Factors,Resistant Genes And Molecular Epidemiology Of Carbapenem-resistant Klebsiella Pneumoniae Infection For Hospital-acquired Pneumonia

PART I Analysis of Risk factors and outcomes of Carbapenem-Resistant Klebsiella pneumoniae Infection for Hospital-Acquired PneumoniaObjective To identify the risk factors for the development and mortality of carbapenem-resistant Klebsiella pneumoniae(CRKP)infection for hospital-acquired pneumonia(HAP);to analyze the outcomes of patients and the microbiologic characteristics of isolates.Methods A total of 148 HAP patients with CRKP infection were collected from January2015 to June 2017 in First Affiliated hospital of Anhui Medical University.The medical data of patients was reviewed by the electronic medical record system.A retrospective,1: 1 matched case-control study was conducted to analyze the risk factors for the development of CRKP infection for HAP.The case group was defined as CRKP-infected patients diagnosed with HAP,and the control group was set up with carbapenem-sensitive Klebsiella pneumoniae(CSKP)infected patients with HAP.In addition,the outcomes of patients and microbiologic characteristics of strains between the two groups were compared,and the antibiotic susceptibility testing of strains was completed by Vitek 2 Compact automatic microbiological analysis system.Moreover,74 CRKP-infected HAP patients were further divided into survival group(n = 26)and death group(n = 48),and the risk factors of crude in-hospital mortality of HAP patients with CRKP infection were further analyzed by the method of case-control study.Results Multivariate analysis results showed that previous peripherally inserted central catheter(PICC),sputum suction,continuous renal replacement therapy(CRRT),and fluoroquinolone use were independent risk factors for the development of CRKP infection for HAP.However,surgery was the only independent risk factor for crude in-hospital mortality of HAP patients with CRKP infection.In addition,compared with CSKP infection,CRKP infection was associated with higher mortality,medical costs and resistance rates to multiple antibiotics.Conclusions Previous PICC,sputum suction,CRRT and fluoroquinolone use are associated with the development of CRKP infection for HAP,and surgery is associated with the mortality.In addition,CRKP infection caused higher financial burden and mortality for the patients.Therefore,effective measures should be taken as early as possible for high-risk patients.Part II Study of Resistance Genes and Molecular Epidemiology of Carbapenem-resistant Klebsiella pneumoniae Infected in Hospital-Acquired PatientsObjective To analyze the resistance genes and molecular epidemiologic characteristics of CRKP-infected isolates,and to acknowledge the characteristics of CRKP infection of different clones.Methods For 74 CRKP-infected strains isolated from HAP patients,the carbapenemase genes were detected by the method of polymerase chain reaction and the molecular epidemiology were analyzed by the method of multilocus sequence typing.In addition,74 CRKP-infected HAP patients were further divided into ST11 group(n = 60)and non-ST11 group(n = 14),and the clinical,microbiologic,and molecular characteristics of CRKP infection between the two groups were compared.Results A total of 68(91.9%)CRKP isolates were positive for the production of carbapenemases,with KPC-2(63/74,85.1%)foremost,followed by NDM-1(4/74,5.4%)and IMP-38like(2/74,2.7%).VIM and OXA-48 were not detected in this study.A total of 13 sequence types(STs)were detected,with ST11(60/74,81.1%)predominant.ST11 CRKP strains have the horizontally and vertically transmission in the hospital.In addition,compared with ones in non-ST11 group,CRKP isolates in the ST11 group were associated with higher detection rate of bla KPC(P = 0.001)and lower resistance rate to trimethoprim /sulfamethoxazole(P = 0.033),but the differences of clinical backgrounds and outcomes of the patients between the groups were not statistically significant.Conclusions KPC-producing ST11 CRKP strains are predominant for HAP in this hospital.Compared with ones in the non-ST11 group,CRKP strains in the ST11 group are associated with the higher detection rate of bla KPC and lower resistance rate to trimethoprim /sulfamethoxazole,but the clinical backgrounds and outcomes of the patients between the groups are similar.