Beyond Resistance: Carbapenemase Gene Profiles and Mortality in ICU Patients with Carbapenem-Resistant Klebsiella pneumoniae Infections

Carbapenem-resistant Klebsiella pneumoniae (CRKP) causes serious infections in intensive care units (ICUs), but the relationship between carbapenemase gene profiles and mortality remains uncertain. This prospective two-center cohort included 94 adult ICU patients with clinical CRKP infection from April to September 2026. The first clinical isolate from each patient was included. bla_KPC, bla_NDM, bla_VIM, bla_IMP, bla_OXA-48, and bla_CTX-M genes were investigated by polymerase chain reaction. The primary outcome was 28-day ICU mortality; 14-day and final ICU mortality were secondary outcomes. bla_OXA-48, bla_NDM, bla_KPC, and bla_CTX-M were detected in 65 (69.1%), 49 (52.1%), 19 (20.2%), and 73 (77.7%) of isolates, respectively; bla_NDM and bla_OXA-48 co-occurred in 39 (41.5%). Fourteen-day, 28-day, and final ICU mortality rates occured in 38 (40.4%), 48 (51.1%), and 53 (56.4%), respectively. No statistically significant associations were observed between individual genes, the presence of two carbapenemase genes, or carbapenemase profiles and any mortality endpoint; adjusted analyses of 28-day ICU mortality yielded similar findings. In the exploratory Firth model, the profile effect was not significant (p = 0.198), whereas a higher age-adjusted Charlson Comorbidity Index and bloodstream infection or ventilator-associated pneumonia, compared with urinary tract infection, were associated with higher odds of 28-day ICU mortality. Frequent gene co-occurrence was observed; however, clinically meaningful gene–mortality associations cannot be excluded because of imprecise estimates.