Validation of an Antimicrobial Stewardship Driven Verigene® Blood-Culture Gram-Negative Treatment Algorithm to Improve Appropriateness of Antibiotics

Abstract

BackgroundGram-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.MethodsRetrospective, 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.Results188 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.ConclusionProposed 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

Antimicrobial de-escalation in critically ill patients: a position statement from a task force of the European Society of Intensive Care Medicine (ESICM) and European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Critically Ill Patients Study Group (ESGCIP)

“…There is very little data on their use for ADE. A recent retrospective study to validate a MRDTbased AMS strategy pointed at a small (4.8%) risk of inappropriate ADE when the test was used [51]. In addition, the association between very early ADE and treatment failure has not been evaluated in any study and no recommendation can be made regarding MRDT and ADE at the time of preparing this document.…”