1926. Evaluation of Safety and Effectiveness of Continuous Infusion Ceftolozane/Tazobactam as Outpatient Parenteral Antimicrobial Therapy

BACKGROUND: Ceftolozane/tazobactam (C/T) is indicated for complicated intra-abdominal infections and complicated urinary tract infections (cUTI). Its spectrum of activity extends to most Gram-negative bacteria including multidrug-resistant (MDR) Pseudomonas aeruginosa and extended-spectrum β-lactamase-producing enterobacteriaceae. Current dosing requires 8-hour intervals in order to meet appropriate concentrations above the MIC, making outpatient delivery logistically difficult. C/T is stable up to 24 hours at room temperature, allowing for potential continuous infusion. This study evaluated patients who received this novel dosing regimen at an outpatient infusion center. METHODS: This study was a nonrandomized, retrospective chart review of adult patients who received C/T August 2016–January 2018 for any indication, including off-label, in the outpatient setting as a continuous infusion. Primary outcome evaluated was symptom resolution at the end of therapy documented in outpatient records. Secondary outcomes were microbiologic resolution at the end of therapy, if available, and patient satisfaction via a modified patient satisfaction survey assessed from follow-up phone call to patient. RESULTS: Seven patients received C/T in the outpatient setting and were included in the study. Infections treated varied and included pneumonia (three), cUTI (two), skin and soft tissue (one), and bacteremia (one). Most patients received 4.5 g (with one receiving 9 g) C/T over 24 hours mixed with normal saline via an ambulatory infusion pump refilled each day at an outpatient infusion center. All seven patients were infected with P. aeruginosa (four being MDR) with one patient co-infected with E. coli. Susceptibility testing was performed on three P. aeruginosa isolates (two susceptible and one intermediate). Six of seven patients reported symptom resolution at the end of therapy. Three patients were microbiologically evaluable at the end of therapy and all three demonstrated microbiologic resolution. Three of seven patients completed the satisfaction survey with all three reporting overall satisfaction. No adverse events were documented from any patients. CONCLUSION: Ceftolozane/tazobactam administered as a continuous infusion in the outpatient setting is a safe, effective, and convenient way to treat complicated P. aeruginosa infections. DISCLOSURES: B. M. Jones, Merck: Grant Investigator, Grant recipient. C. Bland, Merck: Grant Investigator and Speaker’s Bureau, Grant recipient and Speaker honorarium.