Methods: This was a single-center, retrospective cohort study. Adult patients with EBSL-EB bacteremia with E. coli, Klebsiella species, or Proteus mirabilis that were sensitive in vitro to Cbps and PTZ were included. Isolates were presumed to be an ESBL-producing organism if they had a ceftriaxone MIC>1 as per 2010 CLSI recommendations. The 3 treatment exposure arms (Cbp, SI-PTZ, and EI-PTZ) were compared in 2 cohorts: empiric therapy cohort (ET) and definitive therapy cohort (DT). The primary outcome measure was mortality. A multivariable logistic regression analysis was conducted to control for confounding variables.
Results: There were 40 patients in the ET (Cbp, 14; EI-PTZ, 14; SI-PTZ, 14) and 43 patients in the DT (Cbp, 28; EI-PTZ, 8; SI-PTZ, 7). Pitt bacteremia score was associated with increased mortality in both the ET (unadjusted odds ratio [OR], 2.30; 95% confidence interval [CI], 1.21-4.38) and DT (unadjusted OR, 2.25, 95% CI, 1.2-4.21) but was not statistically significant on multivariable analysis. In the DT, EI-PTZ was associated with a higher risk of mortality in the unadjusted analysis (unadjusted OR, 7.8, 95% CI, 1.03-59.33). On multivariable analysis, risk of mortality was not increased for EI-PTZ in both the ET (adjusted OR, 0.81, 95% CI, 0.03-23.86) and the DT (adjusted OR, 1.56, 95% CI, 0.08-29.69).
Conclusion: Antibiotic therapy with PTZ was not associated with a higher risk of mortality in comparison to Cbp therapy in patients with ESBL-EB bacteremia.
R. Jackson, None
J. Lough, None
M. Weinstein, None
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