182. Clinical Implications of Extended Infusion Piperacillin-Tazobactam Therapy
Session: Poster Abstract Session: Antibiotic Stewardship
Friday, October 21, 2011
Room: Poster Hall B1

Background:  Piperacillin-tazobactam (P/T) is often used to treat Pseudomonas aeruginosa (PsA) infections.  P/T exhibits concentration-independent bacterial killing, where time above the minimum inhibitory concentration (MIC) is important to optimize. Based on the favorable outcomes from the study by Lodise et al using extended infusion (EI) of P/T, St. Mary Medical Center implemented an automatic conversion of P/T intermittent infusion (InI) to P/T EI. The primary study objective was to determine the clinical implications of EI of P/T given every 8 hours over 4 hours compared to InI of P/T given every 6 hours over 30 minutes in patients with invasive PsA infections.

Methods:  The pharmacy database was used to identify patients who received P/T. A retrospective chart review was performed. The control group received P/T InI from 7/09 to 6/10 and the study group received P/T EI from 7/10 to 2/11.  Patients were included if they were ≥18 years old, had a positive PsA culture from a respiratory, abdominal, wound, or blood source, and received ≥ 48 hours of P/T within 72 hours of the culture. Patients were excluded if the PsA was intermediate or resistant to P/T. Patients were also excluded from the EI group if they received >1 day of InI.  Patient demographics, relevant laboratory and radiologic findings, and clinical data were collected.  

Results:  There were 32 InI and 24 EI patients. Baseline characteristics between both groups were not significantly different. While a higher percentage of patients had a positive clinical response in the EI group (87.5% vs. 71.9%, p=0.20), it was not statistically significant. When comparing clinical outcomes of patients with invasive PsA infections based on MIC, results favor P/T EI compared to P/T InI in patients with lower MICs of ≤8 or ≤16 (95% vs. 68%, p=0.03). There was no difference in clinical outcomes in patients with higher MICs of ≤32 or ≤64.

Conclusion:  Implementation of P/T EI did not have a negative clinical impact on our patient population. Automatic conversion of P/T to EI continues as a part of the antimicrobial stewardship program.


Subject Category: A. Antimicrobial agents and Resistance

Mai-Chi Hong, PharmD1, Huan Nguyen, PharmD1,2, Cathy Hirokawa, PharmD2 and Megan Nguyen, PharmD1,2, (1)Western University of Health Sciences, Pomona, CA, (2)St. Mary Medical Center, Long Beach, CA


M. C. Hong, None

H. Nguyen, None

C. Hirokawa, None

M. Nguyen, None

Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.