Predictors of mortality in multidrug-resistant Klebsiella pneumoniae bloodstream infections

Abstract

The dramatic increase of antibiotic resistance in Klebsiella pneumoniae has been associated with fatal outcomes. First, bloodstream infections (BSIs) caused by extended-spectrum β-lactamases (ESBL) Enterobacteriaceae have been associated with treatment failure, more recently BSIs caused by carbapenem-resistant K. pneumoniae (CR-KP) have been reported to be fatal in approximately 50% of cases. Severity of underlying disease, intensive care unit stay at infection onset, infection with ESBL or CR-KP strain and delay in administration of appropriate therapy are among the most common risk factors for mortality in patients with K. pneumoniae BSI, while infection source control and early appropriate antimicrobial treatment have been associated with survival. Thus, risk assessment for ESBL and/or CR-KP is mandatory in patients with suspicion of K. pneumoniae BSI. Here, we examine current evidence regarding risk factors for mortality in patients with K. pneumoniae BSI and address the issue of a risk prediction model for CR-KP BSI.

Keywords::

• bloodstream infection
• carbapenem resistance
• extended-spectrum β-lactamases
• Klebsiella pneumoniae
• mortality
• risk assessment

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• • The prevalence of extended-spectrum β-lactamase (ESBL)-producing strains among Klebsiella pneumoniae is as high as 80% in Europe. The impact of ESBL production on outcome of bloodstream infections (BSIs) could be greater for Enterobacteriaceae in general than K. pneumoniae in particular. This discrepancy could be due to virulence determinants expressed by K. pneumoniae isolates per se, such as the capacity of this microorganism for rapid invasion and necrosis of tissue as well as biofilm production.

• • Isolation of a carbapenem-resistant K. pneumoniae (CR-KP) is an independent risk factor for mortality among patients with K. pneumoniae BSI in the observational studies.

• • The studies on risk factors for mortality among patients with CR-KP BSI indicated that elderly patients, those with hematologic disease, cirrhosis, solid organ transplantation (SOT), dialysis and heart failure as underlying diseases and critically ill patients are at highest risk of death, so the best efforts in terms of prevention of the CR-KP BSI should be targeted to these patient populations.

• • Infection source control (i.e., drainage, catheter removal) and carbapenem-based combination regimens have been identified in several studies to be the only modifiable risk factors associated with improved survival in patients with CR-KP BSI.

• • Validated risk models for predicting which colonized patients will develop CR-KP BSI, or the prognosis of these infections have not been proposed. Development of a universal risk model for CR-KP BSI may be difficult to apply because of institutional differences in patient-specific risk factors, infection prevalence and infection control practices.