OBJECTIVE To investigate the molecular epidemiological characteristics of clinical isolates of carbapen-em-resistant Klebsiella pneumoniae(CRKP)resistant to ceftazidime/avibactam(CZA).METHODS From Jan.2022 to Dec.2023,totally 63 strains of non-repetitive CZA-resistant CRKP that were isolated for the first time from hospitalized patients of the First Affiliated Hospital of Nanchang University were enrolled in the study,and 50 strains of CZA-sensitive CRKP were randomly chosen as the research subjects.The drug susceptibility rates of the strains were observed.The drug resistance genes,virulence genes and capsular serotypes of the strains were detected by means of polymerase chain reaction(PCR).The molecular epidemiological characteristics of the strains were observed by using molecular biological techniques such as pulse field gel electrophoresis(PFGE)and multilocus sequence typing(MLST).RESULTS Among the CZA-resistant CRKP strains,45(71.43％)were iso-lated from sputum.The result of drug susceptibility testing showed that the drug resistance rates of the CZA-re-sistant strains to amikacin,aztreonam and minocycline were lower than those of the CZA-sensitive strains(P＜0.05),and the drug resistance rates of the CZA-resistant strains to tigecycline was higher than that of the CAZ-sensitive strains(P＜0.05).The carrying rates of blaKPC,blaNDM,blaSHV-1,blaTEM-1,blaCTX-M,blaqnrS,blaacc(6')-Ib and blarmtB genes of the CZA-resistant strains were relatively high.Among the detected capsular serotypes,K64(n=18,28.57％)was dominant.ST11(n=25,39.68％)was predominant strain among the CZA-resistant CRKP strains.CONCLUSIONS ST11 is dominant among the CZA-resistant CRKP strains.The strains carry with multiple drug resistance genes and virulence genes.The drug resistance rate of the CZA-resistant strains to tigecycline is higher than that of the CZA-sensitive strains,and it is necessary to attach great importance during the clinical treatment.

OBJECTIVE To investigate the molecular epidemiological characteristics of clinical isolates of carbapen-em-resistant Klebsiella pneumoniae(CRKP)resistant to ceftazidime/avibactam(CZA).METHODS From Jan.2022 to Dec.2023,totally 63 strains of non-repetitive CZA-resistant CRKP that were isolated for the first time from hospitalized patients of the First Affiliated Hospital of Nanchang University were enrolled in the study,and 50 strains of CZA-sensitive CRKP were randomly chosen as the research subjects.The drug susceptibility rates of the strains were observed.The drug resistance genes,virulence genes and capsular serotypes of the strains were detected by means of polymerase chain reaction(PCR).The molecular epidemiological characteristics of the strains were observed by using molecular biological techniques such as pulse field gel electrophoresis(PFGE)and multilocus sequence typing(MLST).RESULTS Among the CZA-resistant CRKP strains,45(71.43％)were iso-lated from sputum.The result of drug susceptibility testing showed that the drug resistance rates of the CZA-re-sistant strains to amikacin,aztreonam and minocycline were lower than those of the CZA-sensitive strains(P＜0.05),and the drug resistance rates of the CZA-resistant strains to tigecycline was higher than that of the CAZ-sensitive strains(P＜0.05).The carrying rates of blaKPC,blaNDM,blaSHV-1,blaTEM-1,blaCTX-M,blaqnrS,blaacc(6')-Ib and blarmtB genes of the CZA-resistant strains were relatively high.Among the detected capsular serotypes,K64(n=18,28.57％)was dominant.ST11(n=25,39.68％)was predominant strain among the CZA-resistant CRKP strains.CONCLUSIONS ST11 is dominant among the CZA-resistant CRKP strains.The strains carry with multiple drug resistance genes and virulence genes.The drug resistance rate of the CZA-resistant strains to tigecycline is higher than that of the CZA-sensitive strains,and it is necessary to attach great importance during the clinical treatment.