Clinical Outcomes in Hypervirulent Carbapenem-Resistant Klebsiella pneumoniae Infection: A Cohort Study

BACKGROUND: Klebsiella pneumoniae is a major pathogen with carbapenem resistance and hypervirulence as common evolutional pathways leading to poor outcomes. Hypervirulent carbapenem-resistant K. pneumoniae (hvCRKP) has emerged, typically via acquisition of virulence plasmids encoding hypervirulence factors by CRKP. However, whether hypervirulence worsens patient outcomes in the setting of carbapenem resistance remains unclear. METHODS: We conducted an observational cohort study comprising 3-year (2019-2022) data in a Chinese university hospital. We performed genome sequencing for CRKP strains, compared adult patients infected by hvCRKP with those infected by nonhypervirulent "classic" CRKP (cCRKP), and used propensity score matching for imbalanced baseline characteristics. We defined 30-day all-cause and attributed mortality rates and 30-day ranking outcomes (death, no response/progress, or remission) as primary outcomes and postinfection stay and survival as secondary outcomes. RESULTS: Patients with hvCRKP (n = 262) or cCRKP (n = 294) infection had similar 30-day mortality rates (all-cause, 30.9% vs 33.7% [P = .49]; infection attributed, 24.4% vs 26.2%b [P = .77]), no response/progress rate (19.8% vs 20.4%; P = .72), postinfection hospital stay (median, 13 vs 15 days; P = .19), and postinfection survival (median, 18.5 vs 24.5 days; P = .22). All outcomes were also similar (P > .05) between the 2 groups after propensity score matching and in all subgroup analyses. CONCLUSIONS: The hypervirulence of K. pneumoniae remains not well defined. The concept of hvCRKP in current form should not be overemphasized.