141. Use of Rapid Diagnostic Testing in Gram-negative Bloodstream Infections with and without Antimicrobial Stewardship

BACKGROUND: Verigene Blood Culture Gram-Negative (VBC-GN) is a rapid diagnostic test (RDT) that can detect key GNs and resistance within hours from Gram-stain. Numerous studies have shown that RDTs in BSIs improve clinical outcomes, particularly with active antimicrobial stewardship (AMS) intervention. Little is known regarding outcomes in GN BSI without vs. with AMS intervention. METHODS: A retrospective three-part quasi-experimental study of adult patients with GN BSI from December 2014 to April 2018. VBC-GN was introduced September 2015 and AMS review was implemented October 2017. Antibiotics were appropriate if active in vitro against isolated GN. Optimal antibiotics were not overly broad, accounted for resistance, source of infection, and other infecting organisms. Comparisons were made using Chi-squared for nominal variables and Kaplan–Meier with log-rank for time to event analysis. RESULTS: In total, 772 patients met inclusion. The most common source was urinary (30.1%) and E. coli was the most common GN (37.9%). Infectious Disease consults increased with each group (50.6% vs. 67.9% vs. 81.8%, P < 0.001). More patients pre-RDT (37.36%) and RDT+AMS (35.6%) compared with RDT only (24.6%) were critically ill, P = 0.001. Optimal therapy was achieved in more patients in RDT-only (79%) and RDT+AMS (86%) groups compared with pre-RDT (66%), P < 0.001. More patients in the pre-RDT group (44.7%) were appropriately de-escalated compared with RDT only (31.6%) and RDT + AMS (38.7%), P = 0.026. Appropriate escalation occurred most often in the RDT-only group (39.3%) vs. pre-RDT (15.2%) and RDT + AMS (14.2%), P = 0.019. Median post-BSI length of stay (8.2 vs. 7.1 vs. 8.5 days, P = 0.226) and inpatient mortality (10.8% vs. 14.3% vs. 11.4%, P = 0.493) were similar. CONCLUSION: With the implementation of VBC-GN RDT there was a significantly decreased time to optimal therapy, mainly based on necessary antibiotic escalation. Antibiotic de-escalation remained a challenge, even with active AMS review. [Image: see text] DISCLOSURES: All authors: No reported disclosures.