Impact of carbapenem resistance on the outcome of patients' hospital-acquired bacteraemia caused by Klebsiella pneumoniae

SummaryBackgroundCarbapenem-resistant Enterobacteriaceae, especially Klebsiella spp., have become a major health problem recently worldwide. Since 2006 the incidence of carbapenem-resistant Klebsiella pneumoniae (CRKP) infections has increased substantially in Israel. Bloodstream infections (BSIs) caused by these strains have been associated with high rates of treatment failure and mortality.AimThis study was designed to identify risk factors for carbapenem resistance among patients with healthcare-related (HCR) K. pneumoniae bacteraemia and predictors of mortality associated with HCR-CRKP bacteraemia compared with carbapenem-susceptible K. pneumoniae (CSKP).MethodsIn this retrospective case–control study, all cases of K. pneumoniae bacteraemia during 2006–2008 were identified. Resistance patterns, underlying morbidities, risk factors for drug resistance and mortality rates were compared for patients with CRKP and CSKP bacteraemia.FindingsTwo hundred and fourteen patients with CSKP bacteraemia were compared with 103 patients with CRKP bacteraemia. Severe, chronic comorbidities and prior antibiotic use were more frequent among patients with CRKP bacteraemia. On multivariate analysis prior use of macrolides and antibiotic exposure for ≥14 days remained the only independent factors associated with CRKP bacteraemia. Mortality rates of CRKP patients were significantly higher than those of CSKP patients. On multivariate analyses: bedridden status, chronic liver disease, Charlson comorbidity index ≥5, mechanical ventilation, and haemodialysis remained independently associated with mortality among patients with K. pneumoniae bacteraemia. Carbapenem resistance was not a risk factor for mortality.ConclusionsPrevious antibiotic exposure is a risk factor for CRKP-BSI. Mortality among patients with K. pneumoniae bacteraemia is associated with serious comorbidities, but not with carbapenem resistance.