Clinical and Economic Impact of Bacteremia with Extended- Spectrum-β-Lactamase-Producing Enterobacteriaceae

We studied outcomes of extended-spectrum beta-lactamase (ESBL) production in Enterobacteriaceae bacteremia. Inpatients with bacteremia caused by ESBL-producing Escherichia coli, Klebsiella spp. , or Proteus spp. (cases) were compared with patients with bacteremia caused by non-ESBL producers (controls). Outcomes included mortality, mortality due to infection, length of stay (LOS), delay in appropriate therapy (DAT), discharge to a chronic care facility, and hospital cost. Ninety-nine cases and 99 controls were enrolled. Thirty-five percent of cases died, versus 18% of controls (odds ratio OR, 2. 5; 95% confidence interval CI, 1. 3 to 4. 7; P=0. 01). Thirty percent of cases died due to infection, versus 16% of controls (OR, 2. 3; 95% CI, 1. 1 to 4. 5; P=0. 03). The median LOS after bacteremia for cases was 11 days (interquartile range, 5 to 21), versus 5 days for controls (interquartile range, 3 to 9) (P<0. 001). DAT occurred in 66% of cases, versus 7% of controls (OR, 25. 1; 95% CI, 10. 5 to 60. 2; P<0. 001). Cases were more likely than controls to be discharged to chronic care (52% versus 21%; OR, 4. 0; 95% CI, 1. 9 to 8. 3; P<0. 001). The average hospital cost for cases was 65, 509 Israeli shekels, versus 23, 538 shekels for controls (P<0. 001). After adjusting for differences between groups by using multivariable analysis, ESBL production remained a significant predictor of mortality (OR, 3. 6; 95% CI, 1. 4 to 9. 5; P=0. 008), increased LOS (1. 56-fold; P=0. 001), DAT (OR, 25. 1; 95% CI, 10. 5 to 60. 2; P<0. 001), and increased cost (1. 57-fold; P=0. 003). The mean increase in equivalent cost attributable to ESBL production was 9, 620. ESBL production was associated with severe adverse outcomes, including higher overall and infection-related mortality, increased LOS, DAT, discharge to chronic care, and higher costs.