Epidemiological, phenotypic and genotypic characteristics difference of hypervirulent and carbapenem-resistant Klebsiella pneumoniae with different capsular serotypes.

Background: KL1, KL2 CR-hvKP and KL64, KL47 hv-CRKP all exhibit overlapping multidrug resistance and hypervirulence phenotypes, but the differences in epidemiological, phenotypic and genotypic characteristics between them remains unclear.

Methods: In this study, we collected non-repeated hv-CRKP/CR-hvKP isolates in a tertiary hospital in Shanghai, China from January 2019 to December 2022. Furthermore, we selected four typical hypervirulent and carbapenem-resistant Klebsiella pneumoniae, including ST23-KL1/ST86-KL2 CR-hvKP (WYKP3 and WYKP194) and ST11-KL64/ST11-KL47 hv-CRKP (WYKP589 and WYKP188), and tried to clarify and compare their differences in virulence and drug resistance characteristics and plasmid distribution.

Results: Our study found that ST23-KL1 and ST86-KL2 CR-hvKP exhibited less plasmid diversity than that of ST11-KL64 and ST11-KL47 hv-CRKP. Compared with ST11-KL64 and ST11-KL47 hv-CRKP, ST23-KL1/ST86-KL2 CR-hvKP harbored significantly fewer antimicrobial resistance genes but more virulence genes, which contributed to the higher virulence of these strains and exhibited resistance to fewer antibiotics. ST11-KL64 hv-CRKP has emerged as the most prevalent hypervirulent and carbapenem-resistant Klebsiella pneumoniae probably due to its clonal transmission within hospitals as well as the transmission of virulence plasmids with the help of conjugative resistance plasmids.

Conclusions: Due to the different evolutionary mechanisms of hypervirulent and carbapenem-resistant Klebsiella pneumoniae with different capsular serotypes, the epidemiological, phenotypic and genotypic characteristics of KL1, KL2 CR-hvKP and KL64, KL47 hv-CRKP are different.