2027. Clinical outcome and effectiveness of empiric Piperacillin-Tazobactam versus Carbapenem in the treatment of bloodstream infections caused by ESBL - producing organisms
Session: Poster Abstract Session: Antimicrobial Resistant Infections: Treatment
Saturday, October 29, 2016
Room: Poster Hall
Background: The effectiveness of PTZ for treatment of extended-spectrum β-lactamase (ESBL) bacteremia is controversial. Studies suggest moderate to high in vitro activity of PTZ against ESBLs but this does not necessarily translate to clinical efficacy. Although the addition of tazobactam appears to reduce the hydrolyzing effect of β-lactamases on the β-lactam ring of piperacillin, its activity is diminished when a high concentration of bacteria is present. We sought to determine the impact of empiric PTZ compared with empiric carbapenem on 14-day mortality in patients with ESBL bacteremia.

Methods: Subjects were hospitalized between January 2010 and June 2015 with monomicrobial ESBL bacteremia and received empiric PTZ or carbapenem. To remain in the study, all patients had to receive carbapenem therapy after their bloodstream isolate was identified as ESBL-producing. We analyzed patients based on their level of care and clinical outcome was determined as day of death or discharge.

Results: 79 ESBL blood isolates were included in our study; 35 received empiric PTZ and 44 received empiric carbapenem. The 14-day mortality was 15 (43%) in the empiric PTZ group vs 5 (11%) in the empiric carbapenem group. In a bivariate Cox regression analysis, patients who received carbapenem had 0.32 the hazard rate of those receiving PTZ (95% CI, 0.13-0.79; p=0.013). Patients on the regular medical floor had a lower hazards than those in the ICU (HR 0.046; 95% CI, 0.12-0.96; p=0.003). Twenty-seven patients were known to be colonized with ESBL-producing organisms; 21 of them received empiric carbapenem therapy and 3 received empiric PTZ; these latter 3 died in the first 14 days.

Conclusion: Our results suggest that, in our instituition, carbapenems should be used as preferred empiric therapy for patients at high risk of ESBL bloodstream infections. Poorer clinical outcome in these patients may be attributable to a delay in initiating appropriate antimicrobial therapy. However, the liberal use of carbapenems is not without consequence and can result in the emergence of drug resistance. The decision to use empiric carbapenem therapy should be carefully considered after factoring in relevant data.

Lisa Vanchhawng, MD, Department of Infectious Disease, Albert Einstein Medical Center, Philadelphia, PA and Antonette Climaco, MD, Department of Infectious Diseases, Albert Einstein Medical Center, Philadelphia, PA


L. Vanchhawng, None

A. Climaco, None

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