225. Economic Impact of Rapid Detection of Gram-Positive Organisms in Blood Culture
Session: Poster Abstract Session: Diagnostic Microbiology
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C

The traditional approach of identifying gram-positive organisms in blood cultures requires 1 - 3 days until final results are available. With the advent of molecular-based techniques, rapid identification of these organisms can be achieved in a few hours after the organism is growing in blood culture broth. We set out to assess the economic impact of employing such molecular-based techniques in our institution.


Forty-five positive blood cultures harboring a gram-positive organism were evaluated by conventional workup and Verigene Gram-Positive Blood Culture (BC-GP) Nucleic Acid Test (Nanosphere, Inc., Northbrook, IL). A retrospective analysis was conducted to determine the economic impact of employing Verigene versus conventional workup with regards to cost of: antimicrobial therapy, drug-level monitoring, and hospital admission. Statistical analysis was performed using a t-test or a Mann-Whitney U test for non-normal distributions.


On average Verigene results were available 42 hours prior to conventional workup (p<0.001). The greatest impact was seen for coagulase-negative Staphylococci where seven patients avoided vancomycin therapy and three had vancomycin discontinued. For S. aureus, four patients were found to have MSSA, three were switched from vancomycin to other antibiotic and one avoided institution of vancomycin. A single Group B Streptococcus isolate was identified and vancomycin discontinued in favor of other agent. Two patients with history of vancomycin-resistant Enterococcus avoided daptomycin given Verigene results. Similarly one patient had linezolid discontinued based on S. pneumoniae identification. In total, $1,706 in antibiotic cost was saved for this group. Meanwhile, savings in drug level monitoring amounted to $ 300 for vancomycin. In three patients, the results of the culture were deemed to be contaminants, not needing hospital admission leading to a cost savings of $10,720, based on our institution's cost/day.


Rapid molecular testing of blood cultures denote a clear advantage when compared to conventional workup to identify gram positive bacteria in blood culture and has proven to be a cost effective tool to improve patient care and of antimicrobial stewardship.

Paul Mariani, MD, Infectious Disease, Sanford Health, Fargo, ND, Jesse L. Breidenbach, PharmD, Sanford Health, Fargo, ND and Felix Roth, Ph.D., Molecular Pathology, Sanford Health, Fargo, ND


P. Mariani, None

J. L. Breidenbach, None

F. Roth, None

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