Clinical predictors and outcomes of Klebsiella pneumoniae bacteraemia in a regional hospital in Hong Kong

Abstract

Background: Klebsiella pneumoniae (KP) infection is associated with high morbidity and mortality. Multidrug resistance, especially extended-spectrum β-lactamase (ESBL) production, in KP is endemic worldwide.

Aim: To evaluate the clinical characteristics and outcomes of patients with KP bacteraemia in critical care and general ward settings.

Methods: Adult patients admitted to a regional hospital in Hong Kong from January 1^st, 2009 to June 30^th, 2016 (7.5 years) with KP bacteraemia were included. Demographics, clinical features, microbiological characteristics, and outcomes were analysed.

Findings: Among 853 patients, 178 (20.9%) required critical care and 176 (20.6%) died within 30 days of hospital admission. Thirty-day survivors were younger (P<0.001), had milder disease (defined by Sequential Organ Failure Assessment score) (P<0.001), presented with hepatobiliary sepsis (P<0.001) or urosepsis (P<0.001), less septic shock (P=0.013), fewer invasive organ supports (P<0.001), and had appropriate empirical antibiotics (P<0.001). Cox regression analysis showed that respiratory tract infection (hazard ratio: 2.99; 95% confidence interval: 2.061-4.337; P≤0.001), gastrointestinal tract infection (excluding hepatobiliary system) (2.763; 1.761-4.337; P≤0.001), mechanical ventilation (2.202; 1.506-3.221; P≤0.001), medical case (1.830; 1.253-2.672; P=0.002), inappropriate empirical antibiotics (1.716; 1.267-2.324; P≤0.001), female (1.699; 1.251-2.307; P<0.001), age >65 years (1.692; 1.160-2.467; P=0.006), and presence of solid tumour (1.457; 1.056-2.009; P=0.022) were independent risk factors for 30-day mortality. Unexpectedly, diabetes mellitus was associated with better 30-day survival (P=0.002). A total of 102 patients (12.0%) had infections with ESBL-producing strains, which were not associated with higher 30-day mortality.

Conclusion: KP bacteraemia is associated with high 30-day mortality. Site of infection, patients' comorbidities and appropriate use of empirical antibiotic are important predictors of patients' outcomes.

Keywords: Bloodstream infection; Carbapenemase; Klebsiella pneumoniae; Multidrug resistance; Outcomes; Risk factors.