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Three rapid diagnostic test panels (Verigene BC-GN, BioFire BCID, and BCID 2 [RUO]) were compared using the Desirability of Outcome Ranking Management of Antimicrobial Therapy (DOOR-MAT) to evaluate potential downstream antimicrobial prescribing decisions resulting from the panels’ different organism and resistance detection. BioFire BCID 2 (RUO) had the best mean DOOR-MAT scores.

Decisions regarding which rapid diagnostic test (RDT) for bloodstream infections to implement remain challenging given the diversity of organisms detected by different platforms. We used the desirability of outcome ranking management of antimicrobial therapy (DOOR-MAT) as a framework to compare two RDT platforms on potential desirability of antimicrobial therapy decisions. An observational study was performed at University of Maryland Medical System comparing Verigene blood culture (BC) to GenMark Dx ePlex blood culture ID (BCID) (research use only) panels on blood cultures from adult patients. Positive percent agreement (PPA) between each RDT platform and Vitek MS was calculated for comparison of on-panel targets. Theoretical antimicrobial decisions were made based on RDT results, taking into consideration patient parameters, antimicrobial stewardship practices, and local infectious diseases epidemiology. DOOR-MAT with a partial credit scoring system was applied to these decisions, and mean scores were compared across platforms using a paired t test. The study consisted of 160 unique patients. The Verigene BC PPA was 98.6% (95% confidence interval [CI], 95.1 to 99.8), and ePlex BCID PPA was 98% (95% CI, 94.3 to 99.6). Among the 31 organisms not on the Verigene BC panels, 61% were identified by the ePlex BCID panels. The mean (standard deviation [SD]) DOOR-MAT score for Verigene BC was 86.8 (28.5), while that for ePlex BCID was 91.9 (23.1) (P = 0.01). Both RDT platforms had high PPA for on-panel targets. The ePlex BCID was able to identify more organisms than Verigene, resulting in higher mean DOOR-MAT scores.

Background Rapid diagnostic testing (RDT) technology in bloodstream infections (BSI) has outpaced provider understanding of how to effectively use it. To optimize the use of RDT platforms and antibiotic therapy, decision makers must determine which RDTs to implement at their institutions. A thorough understanding of which platform to choose extends beyond simple analytic measures of sensitivities and specificities and should include a robust analysis of how these RDTs could impact clinical decisions. Methods Retrospective study of adult patients with Gram-negative (GN) BSI from at University of Maryland Medical Center. The clinical microbiology laboratory used Verigene® BC-GN in clinical practice. Discarded blood samples were run on BioFire® FilmArray BCID. Final organism identification/susceptibility, antibiotic exposures, and clinical outcomes were reviewed. DOOR was applied to theoretical therapy decisions based on both actual prescribing adherence to institutional algorithm recommendations; 1 being most and 6 being least desirable (Table 1). A partial credit scoring system was applied to DOOR from most (100) to least desirable (0) outcome. Comparisons were made in a paired manner. Results 77 patients met inclusion. The median age was 58 (IQR 47, 68), 44.2% were in the ICU, and 75.3% had ID consult within 24 hours of BSI. Organism identification included: E. coli (35.1%), K. pneumoniae (23.4%), P. mirabilis (10.4%), S. marcescens (10.4%), Enterobacter spp. (9.4%), P. aeruginosa (3.9%). The only resistance determinant was CTX-M (11.6%). An antibiotic change occurred in 26.2% of cases, divided between antibiotic escalation and de-escalation. Based on the actual utilization of RDT results, median DOOR was not different between BC-GN and BCID (3 [IQR 3.4] vs. 4 [IQR 3.4], P = 0.44). Using a partial credit scoring system, the mean score was not different between platforms (49.8 [SD 26.8] vs. 47.7 [SD 20.3], P = 0.44). Through pairwise comparisons, BC-GN would have resulted in an optimal outcome of 15.3% (95% CI 4.7% to 19.3%) more often than BCID. Conclusion Based on the actual use of RDTs for GN BSI there was no difference in potential clinical outcomes between platforms in this relatively small sample. DOOR is a novel mechanism to quantitate clinical utility and compare RDTs. Disclosures All authors: No reported disclosures.

Background Gram-negative bacteremia (GNB) is associated with significant morbidity and mortality, emphasizing the need for timely, effective antimicrobial therapy. In comparison to conventional diagnostic methods, Verigene® Blood-Culture Gram-Negative (VBC-GN) is a microarray rapid diagnostic test that identifies eight target GN organisms and six genetic resistance determinants. This study examined the potential clinical impact of VBC-GN coupled with a proposed antimicrobial stewardship (AMS)-derived treatment algorithm to guide timely, appropriate antimicrobial therapy in GNB. Methods Retrospective, single-center, study of adult patients (≥ 18 years) with GNB at University of Maryland Medical Center (UMMC) from September 2015 – May 2016. Patient clinical characteristics, co-morbidities, and antimicrobials administered were collected. Appropriateness of antimicrobial therapy was by in vitro susceptibility. Appropriateness of actual empiric antimicrobials received as standard care were compared with theoretical antimicrobials as guided by the UMMC AMS treatment algorithm. Two investigators (KCC and ELH) independently evaluated appropriateness of empiric and algorithm antimicrobial recommendations. Results 188 patients (median age 57.0 (IQR 46.5 – 65.0) years) with GNB were included and 143 (76.1%) were positive for target GN organisms. Eight (4.3%) cases were GN polymicrobial, 8 (4.3%) were CTX-M positive. E. coli was the most common target GN organism (30.3%), and genitourinary was the most common source (29.3%). There was a good level of agreement between reviewers regarding appropriateness of empiric therapy (Kappa = 0.735) and algorithm recommendations (Kappa = 0.855). Overall, the proposed algorithm would have resulted in 88.4% of cases receiving appropriate antimicrobial therapy vs 78.1% actual empiric antimicrobials (P = 0.014). The AMS treatment algorithm would have resulted in 14.4% appropriate de-escalation, 4.8% inappropriate de-escalation, 5.3% appropriate escalation, and 16.0% unnecessary escalation. Conclusion Proposed antibiotics by AMS-derived treatment algorithm applied in conjunction with rapid diagnostic testing would result in a significantly higher proportion of patients receiving appropriate antimicrobial therapy vs. standard care. Disclosures J. K. Johnson, Nanosphere: Grant Investigator, Grant recipient

Background: Abdominal obesity is associated with the development of gastroesophageal reflux disease (GERD) and, subsequently, Barrett's esophagus (BE). Increased body mass index (BMI) and waist-to-hip ratio (WHR) have individually been associated with BE; however, other anthropometric measurements exist and may be more accurate. Abdominal diameter index (ADI, sagittal abdominal diameter divided by thigh circumference) was previously shown to be a more accurate predictor of incident cardiovascular disease compared to other body measurements. Our aim was to examine whether ADI was a more accurate predictor of prevalent BE compared to other anthropometric measurements. Methods: We conducted a case-control study of patients presenting to our institution from October 2013November 2014. Our study population was consecutive Caucasian men with a known history of BE confirmed by endoscopy and histology. We recruited Caucasian male control patients who underwent endoscopy for any reason and who did not have evidence of BE by history or endoscopy. Prior to endoscopy or outpatient visit both groups completed a questionnaire about demographics, smoking status, and medication use and underwent a series of body measurements including height, weight, waist circumference, hip circumference, thigh circumference, and sagittal abdominal diameter using standardized measuring tools. BMI, WHR, and ADI were calculated, and the data was analyzed using SPSS 22.0. Results: A total of 31 BE patients and 42 control patients were recruited. The BE cohort were older (mean age 62.5 vs. 53.2 yrs, p=0.009) and had a higher rate of hiatal hernia (74.2% vs. 19.0%, p