Evaluation of a Prolonged β-Lactam Antibiotic Infusion Policy on Clinical Outcomes in Patients with Pseudomonas aeruginosa Bacteremia

Abstract

Background. Prolonged β-lactam antibiotic infusions achieve superior pharmacokinetic and pharmacodynamic goals, compared with intermittent infusions. In October 2009, our institution changed the standard infusion time for Gram-negative β-lactam antibiotics from 30 minutes to 3 hours. The objective of this study was to evaluate the effect of this practice change on clinical outcomes in patients with Pseudomonas aeruginosa (PSA) bacteremia. Methods. We collected data on all patients with PSA bacteremia treated with an intravenous β-lactam from 01/2004-12/2014, including demographics, microbiology results, treatment regimen, and clinical outcomes such as intensive care unit (ICU)/ hospital length of stay and mortality. We excluded patients with polymicrobial bacteremia or β-lactam resistant PSA that required switching to an alternative antibiotic class within 24 hours of microbiology susceptibility results. We used multivariable linear and logistic regression analysis to compare clinical outcomes before and after the practice change, adjusting for potential confounders. Results. In total, 183 patients were diagnosed with PSA bacteremia. The most common primary anti-PSA β-lactam was ceftazidime, followed by cefepime, in both the pre and post-intervention cohorts. Development of new β-lactam resistance after therapy and recurrence of bacteremia was rare in our cohort. Conclusion. Prolonged β-lactam infusion over 3 hours was associated with decreased ICU length of stay, with a trend towards decreased hospital length of stay compared with intermittent infusions in patients with PSA bacteremia.