| Objective:To understand the prevalence,clinical characteristics,drug resistance,virulence characteristics and molecular characteristics of polymyxin-carbapenem-resistant Klebsiella pneumoniae（Po-CRKP）in our hospital.Methods:Bacterial strains isolated from clinical specimens of inpatients from May 2021 to July 2022 were collected from the Laboratory Department of the First Affiliated Hospital of Nanchang University,and Microflex mass spectrometer was used to identify the strains,using microbroth dilution method and VItek-2 The analyzer conducts a drug susceptibility test,and the results are judged according to the CLSI2022 version standard.The virulence genes（iro N,rmp A,rmp A2,iuc A,and peg-344）,serotype genes（K1,K2,K5,K20,K54,K57,K64）and colistin carried by Klebsiella pneumoniae were detected by PCR technology.Detection of drug resistance-related genes（pmr A,pmr B,pho P,pho Q,mgr B,mcr-1,mcr-2,mcr-3,mcr-4,mcr-5,mcr-6,mcr-7,and mcr-8）and carbon Penem resistance genes（bla KPC-2,bla NDM-1,bla IMP,bla VIM,and bla OXA-48）.The virulence of the strain was preliminarily evaluated by the wire drawing test and the biofilm formation test in vitro,the ST type of the strain was carried out by MLST technology,and the homology analysis was carried out by PFGE technology.Results:1.A total of 38 Po-CRKP strains were collected.The average age of infected patients was 61±21.6 years old,and the male to female ratio was close to 2:1（69.0%:32.0%）,mainly from neurosurgery,ICU and respiratory medicine.The specimens were mainly from sputum（73.6%）.2.Except for ceftazidime/avibactam and tigecycline,the resistance rate of Po-CRKP to all antibiotics in the drug sensitivity test was over 80%.Colistin resistance-related genes were mainly pmr A（100%）,pmr B（100%）,pho P（100%）,pho Q（100%）,mcr-1（89.4%）and mgr B（63%）,and 1 strain carrying the mcr-2 gene.The major carbapenem resistance genes were bla KPC-2（100%）and bla NDM-1（21%）,respectively.3.Among all Po-CRKPs,73.7%had hypermucus phenotype,100%had positive biofilm formation ability,100%carried rmp A2,89.5%carried rmp A,and one strain carried rmp A,rmp A2,iro N,iuc A and peg-344 at the same time.The capsular serotype was mainly K57（94.7%）.4.MLST suggested mainly ST11（94.7%）.PFGE suggested that most of them belonged to claster C and claster E,and some clones propagated.Conclusions:1.The Po-CRKP in our hospital is mainly distributed in neurosurgery,intensive care medicine,respiratory and other departments with intensive care units,and the specimens are mainly from sputum.2.Po-CRKP strains have extensive drug resistance,and the drug resistance gene generally carries bla KPC-2,and mgr B gene deletion,bla NDM-1,and mcr-1 are all detected in some strains.3.The 38 Po-CRKP strains were all highly virulent strains.4.The main molecular type of Po-CRKP is K57-ST11,and there is clonal transmission in the hospital. |
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