Clinical Characteristics, Antimicrobial Resistance Profile, and Risk Factors for Infection and Adverse Prognosis of Klebsiella pneumoniae Bloodstream Infection

Background: Klebsiella pneumoniae bloodstream infection (KP-BSI) represents a global clinical threat, while local prognostic data are scarce in Hebei Province, China. This study aimed to identify risk factors for carbapenem-resistant Klebsiella pneumoniae (CRKP) infection and in-hospital mortality in KP-BSI patients. Methods: A retrospective observational audit was conducted at a provincial tertiary hospital. Adult non-repeat KP-BSI episodes (2022–2025) were divided into CRKP (n = 156) and carbapenem-susceptible Klebsiella pneumoniae (CSKP, n = 357), as well as survivor and non-survivor subgroups. Clinical, laboratory and microbiological data were extracted from electronic medical records. Univariate and multivariate logistic regression analyses were performed. Results: Among 513 KP-BSI cases, CRKP detection rate was 30.4% and the overall in-hospital mortality was 25.0%. CRKP isolates showed extensive multidrug resistance, with low resistance to colistin (3.5%) and tigecycline (49.0%). Advanced age (per 10-year increment), male sex, invasive procedures, empirical antimicrobial therapy and pre-existing respiratory disease were independent risk factors for CRKP infection. quick Pitt bacteremia score (qPitt score) ≥ 2 and intensive care unit (ICU) admission independently predicted in-hospital mortality; CRKP bacteremia was not an independent mortality predictor after confounder adjustment. Multisite KP isolation occurred in 44.4% of patients, most frequently from the respiratory tract. Conclusions: CRKP-BSI imposes a considerable resistance burden. Infection control should target high-risk patients: elderly males with respiratory comorbidities undergoing invasive procedures. Mortality depends on disease severity (qPitt score, ICU admission), not carbapenem-resistance status. qPitt-based risk stratification and antimicrobial stewardship are essential to improve patient outcomes.