Treatment and outcomes in carbapenem-resistant Klebsiella pneumoniae bloodstream infections

Abstract

Carbapenem-resistant Klebsiella pneumoniae (CR-Kp) is an emerging multidrug-resistant nosocomial pathogen. This is a retrospective chart review describing the outcomes and treatment of 60 cases of CR-Kp bloodstream infections. All CR-Kp isolated from blood cultures were identified retrospectively from the microbiology laboratory from January 2007 to May 2009. Clinical information was collected from the electronic medical record. Patients with 14-day hospital mortality were compared to those who survived 14 days. The all-cause in-hospital and 14-day mortality for all 60 CR-Kp bloodstream infections were 58.3% and 41.7%, respectively. In this collection, 98% of tested isolates were susceptible in vitro to tigecycline compared to 86% to colistimethate, 45% to amikacin, and 22% to gentamicin. Nine patients died before cultures were finalized and received no therapy active against CR-Kp. In the remaining 51 patients, those who survived to day 14 (n = 35) were compared to nonsurvivors at day 14 (n=16). These patients were characterized by both chronic disease and acute illness. The 90-day readmission rate for hospital survivors was 72%. Time to active therapy was not significantly different between survivors and nonsurvivors, and hospital mortality was also similar regardless of therapy chosen. Pitt bacteremia score was the only significant factor associated with mortality in Cox regression analysis. In summary, CR-Kp bloodstream infections occur in patients who are chronically and acutely ill. They are associated with high 14-day mortality and poor outcomes regardless of tigecycline or other treatment regimens selected.

Figure 1

In vitro susceptibility of carbapenem-resistant Klebsiella pneumoniae isolates.

Figure 2

Survival after positive blood culture for carbapenem-resistant Klebsiella pneumoniae (n=51). Nine patients who died prior to cultures being finalized and received no CR-Kp-active therapy were excluded. Data is censored at the time of hospital discharge.