1107. Evaluating Use Of MALDI-TOF For Blood Culture Isolate Identification In A Four Hospital System
Session: Poster Abstract Session: Molecular and Nucleic Acid Testing Diagnostics
Friday, October 9, 2015
Room: Poster Hall
Posters
  • MALDITOF poster IDSA 10.7.15.pdf (467.1 kB)
  • Background: Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) is utilized in healthcare settings to analyze blood, respiratory, wound, and urine samples.  MALDI-TOF can be used to identify the organism, followed by Verigene® Gram-Positive Blood Culture Test (BC-GP) to identify resistance markers for Staphylococcus aureus and Enterococcus spp, with significant shortened total time to identification.  Average time to identification and susceptibility results is 48-72 hours for Phoenix™, 2.5 hours for identification and resistance markers using Verigene® BC-GP, and 30 minutes with MALDI-TOF. Cost to run one sample using Verigene® BC-GP is $70, whereas MALDI-TOF is $5.50 per sample.  We validated MALDI-TOF against Phoenix™ using blood samples and determined if MALDI-TOF is effective in impacting patient care and being cost-effective.

    Methods: Retrospective, descriptive, observational study analyzing 113 blood samples collected from October 2014 through April 2015.  Positive blood samples identified by traditional culture method Phoenix™, then analyzed using MALDI-TOF within 48 hours of confirmed positive gram-positive (GP), gram-negative (GN), anaerobe or yeast organism. Reference used to analyze samples is integrated into the BioTyper software version 3.1.0.4 and compared to a research use only database.  Each isolate given a spectral score, evaluated using software, and confirmed correct identification if score value > 2.0 at species level or > 1.7 but < 2.0 at genus level.

    Results: Total of 113 (48GP, 40GN, 14 anaerobe, and 11 yeast) analyzed using MALDI-TOF. Thirty-six (90%) GN, twenty-nine (60%) GP , nine (64%) anaerobe, and three (27%) yeast organisms were correctly identified using MALDI-TOF. Time to identification per organism using MALDI-TOF was 30 minutes. 

    Conclusion: Achieved 90% concordance with GN, 60% with GP, 64% with anaerobes, and 27% with yeast organisms.  Annual cost savings using MALDI-TOF for initial gram-positive identification is approximately $57,000 and dramatically shortens time to identification.  This has a direct positive impact on patient care. 

    Adrienne Kercsak, PharmD, Eva Sullivan, PharmD and Harminder Sikand, PharmD, FCSHP, FASHP, Scripps Mercy Hospital, San Diego, CA

    Disclosures:

    A. Kercsak, None

    E. Sullivan, None

    H. Sikand, None

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 7th with the exception of research findings presented at the IDWeek press conferences.