Impact of the MIC of Piperacillin-Tazobactam on the Outcome of Patients with Bacteremia Due to Extended-Spectrum-β-Lactamase-Producing Escherichia coli

We investigated the impact of the piperacillin-tazobactam MIC in the outcome of 39 bloodstream infections due to extendedspectrum-beta-lactamase-producing Escherichia coli. All 11 patients with urinary tract infections survived, irrespective of the MIC. For other sources, 30-day mortality was lower for isolates with a MIC of <= 2 mg/liter than for isolates with a higher MIC (0% versus 41.1%; P = 0.02).