Factors Associated with Nosocomial Bloodstream Infection Caused by Carbapenem-Resistant Klebsiella pneumoniae and With Mortality, from a Single Center

Abstract

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is an emerging multi-drug nosocomial pathogen. We compared factors associated with bloodstream infection (BSI) caused by CRKP and carbapenem-sensitive K. pneumoniae (CSKP) and risk factors associated with mortality. A retrospective cohort design was conducted by our tertiary-care university teaching hospital with 3000 beds. All adults with CRKP and CSKP BSI from January 2010 to December 2016 were included. CRKP and CSKP BSI isolated from blood culture were identified retrospectively in the microbiology laboratory. Demographic and clinical characteristics were collected from electronic medical records. Multivariate analysis was used to examine risk factors of mortality, estimating odds ratios (ORs) and 95% confidence intervals (CIs). This study included 140 patients, 29 with CRKP BSI and 111 with CRSP BSI. Patients with CRKP BSI had undergone more invasive procedures, tended to have more comorbidities measured by the Charlson index, and had higher rates of previous antimicrobial exposure than those with CRSP BSI. The crude and attributable mortality at 4 weeks for the 29 patients with CRKP BSI was 41.4% and 25.9%, respectively. On multivariate analysis, factors associated with increased mortality with CRKP BSI were use of ventilation (OR 13.6, 95% CI 3.0-62.3) and tigecycline treatment (110.5, 5.8-2096.2) and appropriate antibiotics empirical therapy was associated with decreased mortality (0.01, 0.001-0.086). Summary, risk factors for CRKP BSIrelated mortality were ventilation, tigecycline treatment and inappropriate antibiotics empirical therapy. The higher mortality associated with CRKP than CSKP BSI may be mediated by failure to provide effective therapy.