Carbapenem Therapy is Associated with Improved Survival Compared to Piperacillin-Tazobactam for Patients with ESBL Bacteremia.
Clin Infect Dis. 2015 Jan 13;
Authors: Tamma PD, Han JH, Rock C, Harris AD, Lautenbach E, Hsu AJ, Avdic E, Cosgrove SE, for the Antibacterial Resistance Leadership Group
BACKGROUND: The effectiveness of piperacillin-tazobactam (PTZ) for the treatment of ESBL bacteremia is controversial. We compared 14-day mortality of PTZ vs. carbapenems as empiric therapy in a cohort of patients with ESBL bacteremia who all received definitive therapy with a carbapenem.
METHODS: Patients hospitalized between January 2007 and April 2014 with monomicrobial ESBL bacteremia were included. A decrease of >3 doubling dilutions in the minimum inhibitory concentration for third-generation cephalosporins tested in combination with 4 µg/ml of clavulanic acid was used to confirm ESBL status. The primary exposure was empiric therapy, defined as antibiotic therapy administered to a patient before ESBL status was known. Patients were excluded if they did not receive a carbapenem after ESBL production was identified. The primary outcome was time to death from the first day of bacteremia. Propensity scores using inverse probability of exposure weighting (IPW) were used to estimate the probability that a patient would receive PTZ versus carbapenems empirically. We calculated overall hazard ratios for mortality censored at 14 days using Cox proportional-hazards models on an IPW-adjusted cohort.
RESULTS: A total of 331 unique patients with ESBL bacteremia were identified. One-hundred and three (48%) patients received PTZ empirically and 110 (52%) received carbapenems empirically. The adjusted risk of death was 1.92 times higher for patients receiving empiric PTZ compared with empiric carbapenem therapy (95% CI, 1.07-3.45).
CONCLUSIONS: PTZ appears inferior to carbapenems for the treatment of ESBL bacteremia. For patients at high risk of invasive ESBL infections, early carbapenem therapy should be considered. Our findings should not be extended to beta-lactam/beta-lactamase inhibitor combinations in development as limited clinical data are available for these agents.
PMID: 25586681 [PubMed - as supplied by publisher]