Risk Factors of Mortality in Patients with Bloodstream Infections Due to Carbapenem Resistant Klebsiella pneumoniae

Objective: Carbapenem-resistant Klebsiella pneumoniae (CRKp) is among the leading causes of hospital-acquired infections worldwide and causes serious and life-threatening infections. Treatment options are very limited for blood stream infections (BSIs) and prognosis is poor due to increasing multi-drug resistance. The aim of this study was to assess risk factors for the mortality due to CRKp-BSI. Methods: A retrospective study was conducted in a university hospital from September 2013 to October 2017. Patients (aged >16 years) with CRKp-BSI were included in this study. Data, including demographics, Charlson comorbidity index (CCI), acute physiology and chronic health evaluation II (APACHE II) score on hospitalisation date, minimum inhibitory concentration (MIC) of CRKp, antibiotic treatment and outcome (30-day mortality) data were collected from the electronic medical records and microbiology databases. Results: A total of 82 patients with CRKP-BSIs were analysed. The median age was 54.5 years, and 48 (58.5%) of them were male. The median APACHE II score on hospitalisation was 14 (IQR 6-28) and CCI was 4.0 (IQR 0-12). Forty-six (56.1%) patients had ICU-acquired bacteremia and 36 (43.9%) had central-line associated bacteremia and 25 (30.5%) had primary bacteremia. Fifty (61.0%) patients had combination therapy, colistin/tigecycline (28%) was the most used antibiotic combination. The mortality of all patients was 56.1% (46/82) and 65.2% (30/46) in ICU patients. In univariate analysis, risk factors for the mortality of CRKp-BSI were high CCI, not having clinical response on the fifth day of treatment, high APACHE II score on hospitalisation and infection date and multiple organ dysfunction syndrome. In multivariate analysis, the most significant risk factor for mortality was APACHE II score on infection day (OR: 1.190; 95% CI: 1.088-1.301). Treatment regimens and combination therapy vs. monotherapy were not found to be significantly associated with survival. In addition, MIC values of CRKp were not associated with mortality. Conclusions: Patients with CRKp-BSI had high mortality (56.1%). APACHE II score on infection day was significantly associated with mortality. The outcome was similar between patients receiving combination (54.3%) or monotherapy (45.7%).