Abstract:Objective To analyze the clinical characteristics, genotypes and major virulence factors of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolated from lower respiratory specimens of patients with ventilator-associated pneumonia (VAP). Methods Non-repetitive Klebsiella pneumoniae (KP) isolated from lower respiratory tract specimens of VAP patients in a hospital from January to December 2019 were collected, clinical characteristics, antimicrobial resistance, multilocus sequence typing and capsular wzi typing of patients were compared between CRKP group and non-CRKP (nCRKP) group, carrying status and homology of virulence factors of CRKP were analyzed. Results A total of 56 strains of KP were collected, 60.7% (n=34) of which were CRKP. The proportion of patients with intensive care unit (ICU) stay≥20 days, death and discharged voluntarily in CRKP group were all higher than those in nCRKP group (all P < 0.05). Resistance rate of CRKP group to commonly used antimicrobial agents was higher than that of nCRKP group (all P < 0.05). Most CRKP (97.1%) carried blaKPC-2 gene, resistance rates to antimicrobial agents other than tigecycline were high. 82.4% of CRKP were ST11 type and K64 was the main capsule type (50.0%); 45.4% of nCRKP were ST11 type and K47 was the main capsule type (40.9%); proportion of K64 type in CRKP was higher than that of nCRKP strain (P < 0.01). CRKP carried a variety of virulence factors, virulence factors rmpA2, iucA and iroN mediated by pLVPK-like plasmid were mainly carried by K64-ST11 CRKP, PFGE analysis showed that there was clonal transmission of K64-ST11 CRKP. Conclusion CRKP isolated from VAP lower respiratory tract specimens shows multiple resistance, and its main molecular type is K64-ST11, this type carries a variety of plasmid-mediated virulence factors and has clonal transmission, clinical epidemic trend should be closely monitored.