Impact of appropriate empirical antibiotics on clinical outcomes in Klebsiella pneumoniae bacteraemia

Introduction: Klebsiella pneumoniae infections can cause septic shock, multiorgan failure, and death. Methods: This retrospective cohort study included adults with K pneumoniae bacteraemia treated from 1 January 2009 to 30 June 2017. Demographics, microbiology, and outcomes were analysed. The primary outcome was 90-day all-cause mortality; secondary outcomes were intensive care unit (ICU) and hospital mortalities, ICU and hospital lengths of stay, and ICU ventilator duration. Results: In total, 984 patients had K pneumoniae bacteraemia; of them, 686 received appropriate empirical antibiotics. Overall, 205 patients required intensive care. Older age (odds ratio [OR]=1.60; 95% confidence interval [CI]=1.120-2.295; P=0.010), chronic kidney disease (OR=1.81; 95% CI=1.181-2.785; P=0.007), mechanical ventilation (OR=1.79; 95% CI=1.188-2.681; P=0.005), pneumonia (OR=1.50; 95% CI=1.030-2.187; P=0.034), and carbapenem-resistant or extended-spectrum beta-lactamase (ESBL)-producing isolates (OR=12.51; 95% CI=7.886-19.487; P<0.001) were associated with greater risk of inappropriate empirical treatment. Ninety-day mortality was significantly higher among patients with inappropriate empirical treatment; independent predictors included pneumonia (hazard ratio [HR]=2.94; 95% CI=2.271-3.808; P<0.001), gastrointestinal infection (HR=2.77; 95% CI=2.055-3.744; P<0.001), failed empirical antibiotics (HR=2.45; 95% CI=1.928-3.124; P<0.001), older age (HR=1.79; 95% CI=1.356-2.371; P<0.001), solid tumour (HR=1.77; 95% CI=1.401-2.231; P<0.001), carbapenem-resistant or ESBL-producing isolates (HR=1.64; 95% CI=1.170-2.297; P=0.004), patients admitted through the Department of Medicine (HR=1.39; 95% CI=1.076-1.800; P=0.012), and higher total Sequential Organ Failure Assessment score (HR=1.09; 95% CI=1.058-1.112; P=0.023). Among ICU patients, inappropriate empirical antibiotic treatment was significantly associated with increased ventilator duration and 90-day mortality. Conclusions: Klebsiella pneumoniae bacteraemia was associated with high 90-day and ICU mortalities; 90-day mortality increased with inappropriate empirical antibiotic treatment.