Antimicrobial resistance and plasmidome of carbapenemase-resistant Klebsiella pneumoniae causing bloodstream infections between 2014 and 2024

The WHO has designated carbapenemase-resistant Klebsiella pneumoniae (CRKP) as a priority pathogen due to the potential for nosocomial infection outbreaks. In this study, a total of 724 non-duplicated K. pneumoniae bloodstream infection isolates were collected in Beijing between 2014 and 2024, of which 14.5% were identified as CRKP (n = 105). The incidence of CRKP isolates remained at a relatively high level since 2018, with a significant increase observed following the SARS-CoV-2 epidemic. The most common sequence type was ST11 (84.8%), followed by ST16 (5.7%) and ST15 (5.7%). Sixteen potential clonal transmissions were identified, including four clonal clusters transmitted at the ward-level. Antimicrobial resistance was severe, with almost all isolates showing resistance to 15 antimicrobials tested. The bla KPC-2 (93.3%) was the dominated carbapenemase gene, followed by bla OXA-181 (5.7%). The bla CTX-M-65 (61.0%) was the most common ESBL gene, followed by bla CTX-M-15 (14.3%) and bla SHV-12 (12.4%). Phenotype-genotype concordance was 100% for cephalosporins and carbapenemases. The correlation of plasmids with antimicrobial resistance and virulence genes were determined, with the IncFII(pHN7A8)_1_pHN7A8 plasmid showing a significant correlation with bla CTX-M-65 and bla KPC-2 , and the IncHI1B_1_pNDM-MAR and IncR_1 plasmids significantly correlated with iucABC-iutA ( P < 0.05). The trend of type KL64 was increasing and surpassed that of type KL47 since 2019, similar to the trend of O2a gradually surpassing O13. Our study provides insights into the epidemiology, dissemination, AMR genes, and plasmids of CRKP bloodstream infections in Beijing, China, over the long term.