1489. Development and implementation of a treatment algorithm for Gram-positive bloodstream infections identified by a Gram-positive nucleic acid microarray assay
Session: Poster Abstract Session: Antimicrobial Stewardship: Role of Diagnostics
Saturday, October 10, 2015
Room: Poster Hall
Posters
  • IDWeek_Poster_1489.pdf (115.0 kB)
  • Background: Bloodstream infections are a major cause of morbidity and mortality in the United States, with mortality estimated at up to 40%. The rapid identification of causative organisms and initiation of appropriate antimicrobial therapy are key predictors of mortality. Routine blood culture techniques can take up to 2-3 days for identification and susceptibilities of causative organisms. The Nanosphere Verigene® Gram-positive blood culture assay (BC-GP) is a rapid molecular nucleic acid microarray capable of identifying twelve bacterial targets and three genetic antibiotic resistance markers. 

    Methods: A retrospective chart review was conducted at the University of Minnesota Medical Center, Fairview from October 2014 until December 2014. Patients identified with a possible Gram-positive bloodstream infection by BC-GP were screened for inclusion. Patients were included if they had a mono-microbial Gram-positive bloodstream infection and were admitted to the hospital. Patients were excluded if they were <18 years of age, pregnant, or opted out of the study. 

    Results: A total of 96 positive blood cultures with Gram-positive cocci or bacilli by Gram-stain were analyzed by BC-GP. The organisms identified by the BC-GP assay were Staphylococcus epidermidis 37.5%, Staphylococcus species 18.75%, Enterococcus faecium 9.3%, Staphylococcus aureus 8.3%, Enterococcus faecalis 5.2%, Streptococcus species 4.1%, Streptococcus agalactiae 3.1%, Streptococcus pneumoniae 1%, Streptococcus pyogenes 1% and no targets 14.5%. When compared with routine culture results, BC-GP organism identification and resistance gene identification for mecA and vanA/B were concordant 97.9% (94/96), 95.1% (39/41), and 92.8% (13/14) of the time, respectively. The mean time to BC-GP results was 3 hours, 24 hours sooner than traditional identification and 31 hours sooner than susceptibilities. Mean vancomycin and antipseudomomal antibiotic duration were 3.4 days and 3.7 days, respectively. 

    Conclusion: The BC-GP assay provided rapid accurate identification of Gram-positive bloodstream infections. In order to improve utilization of BC-GP results and decrease broad-spectrum antibiotic use, a treatment algorithm was developed, and made available to the medical staff.

    Brenton Bastian, PharmD, MS1, Kimberly Boeser, Pharm D, BCPS AQ-ID1 and Patricia Ferrieri, MD, FIDSA2, (1)Pharmacy, University of Minnesota Medical Center, Fairview, Minneapolis, MN, (2)Department of Laboratory Medicine and Pathology, University of Minnesota Medical Center, Fairview, Minneapolis, MN

    Disclosures:

    B. Bastian, None

    K. Boeser, None

    P. Ferrieri, None

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