BackgroundThe antibiotic timeout (ATO) is a stewardship tool that protocolizes review of objective clinical data after a predefined period of time and encourages antimicrobial regimen re-assessment.MethodsVizient member hospitals were utilized to recruit a variety of acute healthcare institutions, including institutions with and without an ATO process. Participating institutions submitted de-identified patient-level antibiotic therapy courses from a single day within a 5-week window to create a snapshot of overall antibiotic utilization. Therapy courses were evaluated on metrics including the prevalence of anti-pseudomonal agents, agents active against methicillin-resistant Staphylococcus aureus (MRSA), and oral (vs. intravenous) antibiotics. The outcome measures included: percent changes in prevalence of courses with antipseudomonal and anti-MRSA agents after day 3, and percent change in antibiotics ordered for oral administration after day 3. These outcome measures were compared between ATO institutions and non-ATO institutions.ResultsA total of 6,184 antibiotic therapy courses were collected from 61 participating institutions (17 ATO institutions; 44 non-ATO institutions). Of 71 institutions that completed enrollment survey, 10 did not complete submission of therapy course data. Antibiotic courses prescribed for prophylaxis (n = 975) and courses that extended beyond 7 days (n = 1,192) were excluded from analysis, resulting in an analysis group that included 4,017 therapy courses (1,396 from ATO institutions vs. 2,621 from non-ATO institutions). The prevalence of patients receiving anti-pseudomonal agents increased after day 3 by 3.03% (P = 0.28) at ATO institutions and decreased 0.45% (P = 0.84) at non-ATO institutions. The prevalence of patients receiving anti-MRSA agents decreased after day 3 by 2.16% (P = 0.41) at ATO institutions and decreased 5.05% (P = 0.005) at non-ATO institutions. Oral antibiotic use increased after day 3 by 3.09% (P = 0.08) at ATO institutions while use at non-ATO institutions increased 7.99% (P = 0.0001).ConclusionAntibiotic therapy course data collected across multiple sites provided no evidence for improved antimicrobial utilization among institutions that have implemented an antibiotic timeout compared with institutions without a timeout. Disclosures All authors: No reported disclosures.