144. Organism Identification and Antibiotic Susceptibilities with Verigene Blood Culture Assay: a Retrospective Single-Center Study

BACKGROUND: The Verigene blood culture assay is a rapid molecular testing platform for positive blood cultures. Verigene detects a limited number of bacteria and a limited number of antibiotic resistance determinants. While certain Verigene results have clear implications for optimal antibiotic therapy prior to complete antibiotic susceptibility testing, others do not. The purpose of this study was to compare the results of the Verigene blood culture assay with standard organism identification and antibiotic susceptibility testing. METHODS: This was a retrospective cohort study conducted at a single academic medical center. The study period was 14 months from November 2017 to December 2018. All Verigene results from the study period were reviewed and compared with the results of standard organism identification and susceptibility testing. Organism identification and antibiotic susceptibility testing were performed by Vitek MS and Vitek 2. Duplicate results from the same patient were excluded. The primary outcome was the percentage of blood cultures correctly identified by Verigene. Secondary outcomes included the antibiotic susceptibility of organisms identified by Verigene in the presence and absence of resistance determinants and the identity and frequency of organisms not detected by Verigene. RESULTS: A total of 782 Verigene results were screened. After exclusions, 675 Verigene results including 737 organisms from 597 patients were included. Of 737 organisms, Verigene correctly identified 611 (82.9%), incorrectly identified 19 (2.6%) and was unable to identify 107 (14.5%) off-panel organisms. Tables 1 and 2 outline the antibiotic susceptibility of organisms by the presence or absence of resistance determinants in Gram-negative and Gram-positive bacteria, respectively. Table 3 describes the identities of the organisms not detected by Verigene, stratified by Gram stain result. CONCLUSION: The Verigene blood culture assay demonstrated accuracy in identifying organisms and predicting antibiotic susceptibility. These results will help inform the prospective interpretation of Verigene results and subsequent antibiotic selection at the study institution. [Image: see text] [Image: see text] [Image: see text] DISCLOSURES: All authors: No reported disclosures.