1863. Molecular Diagnostics Can Lead To Early Optimization of Antimicrobial Therapy For Staphylococcal Bacteremia: Experience at a Large Tertiary-Care VA Medical Center
Session: Poster Abstract Session: Antibiotic Stewardship: Diagnostics
Saturday, October 29, 2016
Room: Poster Hall
Background: Our facility has adopted a high-reliability molecular diagnostics system (Verigene®) for rapid identification of bacteria in blood cultures, including distinction between methicillin-resistant (MR) Staphylococcus aureusbacteremia (SAB), methicillin-susceptible (MS) SAB, and bacteremia with coagulase-negative staphylococci (CoNS-B). Results are available within 2 hours after detection of growth and 2 days sooner than conventional cultures. Here, we evaluated the impact of this system on achieving optimal antimicrobial therapy (OT) for SAB.

Methods: All episodes of staphylococcal bacteremia at our VAMC over 21 months were reviewed. Outpatients and polymicrobial bacteremias were excluded. The primary endpoints were the times from molecular result to placement of an order for OT (an anti-staphylococcal beta-lactam for MS-SAB, or vancomycin or daptomycin for MR-SAB), and times to discontinuation (DC) of unnecessary antibiotics when CoNS was identified as a contaminant in blood.

Results: 25 episodes of MR-SAB, 31 of MS-SAB, and 73 of contaminant CoNS-B were included. Molecular results were available a mean of 1.4 days after blood culture collection. After excluding 3 subjects who died within 24h (all MS-SAB), we classified SAB episodes into 3 groups: 1) OT achieved before results of molecular test available (17 subjects with MR-SAB); 2) OT achieved after molecular test results (median time to OT, 0.42 days; 13 subjects with MS-SAB and 7 with MR-SAB), and 3) OT achieved after culture data (median time to OT 2.32 days; 15 subjects with MS-SAB and 1 subject with MR-SAB). Contaminant CoNS-B were clustered into 3 groups: 1) inappropriate therapy never started (50 subjects), 2) DC of inappropriate therapy occurred before or soon after molecular result (median time to DC 0.9 days; 11 subjects), and 3) DC of therapy occurred post-culture result (median time to DC 2.1 days; 12 subjects).

Conclusion: When used properly, rapid molecular diagnostics led to earlier optimization of therapy for SAB, especially MS-SAB, as well as earlier DC of unnecessary treatment of CoNS-B. However, provider education and reporting modifications to improve timely communication and facilitate interpretation will further maximize the benefits of this technology.

Kelly Rudd, PharmD, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, Sharanie Sims, Pharm.D., BCPS (AQ-ID), Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, Brigid Wilson, PhD, Louis Stokes Veterans Affairs Medical Center, Cleveland, OH, Amy Hirsch, Pharm.D., BCPS, Pharmacy, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, Federico Perez, MD, Louis Stokes Cleveland VA M, Cleveland, OH and Usha Stiefel, M.D., Case Western Reserve University School of Medicine, Cleveland, OH


K. Rudd, None

S. Sims, None

B. Wilson, None

A. Hirsch, None

F. Perez, None

U. Stiefel, None

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