Bloodstream infection due to extended-spectrum beta-lactamase (ESBL)-positive K. pneumoniae and E. coli: an analysis of the disease burden in a large cohort

The burden of extended-spectrum beta-lactamase (ESBL)-positive Enterobacteriaceae (ESBL-E) is growing worldwide. We aimed to determine the financial disease burden attributable to ESBL-positive species in cases of bloodstream infection (BSI) due to K. pneumoniae and E. coli. We conducted a cohort study on patients with BSI due to K. pneumoniae or E. coli between 2008 and 2011 in our institution. Data were collected on true hospital costs, length of stay (LOS), basic demographic parameters, underlying diseases as Charlson comorbidity index (CCI) and ESBL positivity of the pathogens. Multivariable regression analysis on hospital costs and length of stay was performed. Overall we found 1,851 consecutive cases of ESBL-E BSI, 352 (19.0 %) cases of K. pneumoniae BSI and 1,499 (81.0 %) cases of E. coli BSI. Sixty-six of E. coli BSI (18.8 %) and 178 of K. pneumoniae BSI (11.9 %) cases were due to ESBL-positive isolates, respectively (p = 0.001). 830 (44.8 %) cases were hospital-onset, 215 (61.1 %) of the K. pneumoniae and 615 (41.0 %) of the E. coli cases (p < 0.001). In-hospital mortality was overall 19.8, 25.0 % in K. pneumoniae cases and 18.5 % in E. coli cases (p = 0.006). Increased hospital costs and length of stay were significantly associated to BSI with ESBL-positive K. pneumoniae. In contrast to BSI due to ESBL-positive E. coli, cases of ESBL-positive K. pneumoniae BSI were associated with significantly increased costs and length of stay. Infection prevention measures should differentiate between both pathogens.