1488. Assessing the Impact of an Antimicrobial Stewardship Program with a Rapid Organism Detection Assay in the Treatment of Patients with Positive Blood Cultures
Session: Poster Abstract Session: Antimicrobial Stewardship: Role of Diagnostics
Saturday, October 10, 2015
Room: Poster Hall
  • IDSA poster MALDI.pdf (539.8 kB)
  • Background:

    Matrix-assisted laser desorption ionization/time of flight mass spectrometry (MALDI-TOF) is technology that can decrease the time to organism identification by 24 hours when compared conventional blood culture methods.  Earlier organism identification may help de-escalate empiric therapy to a more targeted regimen.  The purpose of this study is to assess the clinical impact of MALDI-TOF with antibiotic stewardship intervention on the treatment of patients with positive blood cultures.


    This is a 2-phased retrospective chart review study.  The first phase included patients with positive blood cultures during Jan-Feb 2014.  Phase 2 included patients after the implementation of MALDI-TOF in Jan-Feb 2015.  Patients were excluded if they failed to receive antibiotics or if aged < 18.  Information to be collected included: demographics, culture result, antibiotics used, adverse events, and LOS.  Appropriate statistical analysis was utilized.


    207 patients were included (n=94 phase 1, n=113 phase 2).  The 2 groups were well-matched in terms of sex, age, co-morbidities, and immunosuppresion.  More patients with acute kidney injury were enrolled in phase 2 (P = 0.0024).  For the organism morphology, both phases had a similar distribution with a predominance of Gram-positive cocci in clusters (58% vs. 48% in phase 1 & 2), then followed by Gram-negative rods (27% vs. 28% in phase 1 & 2).  There was a reduction of 2.4 hours in time to positive blood cultures and 2.7 hours in time to prelimary results after the implementation of MALDI-TOF.  There was an improvement of 14.4 hours in time to optimal therapy after MALDI-TOF implementation (P = 0.04).  There was a decrease in overall hospital use of vancomycin, imipenem, and cefepime but a slight increase in piperacillin-tazobactam use.  The average of days of therapy administered was reduced by 3.5 days in true infections.  There was no difference in adverse events, ICU admission, or 30-day all-cause mortality.  There was a decrease in length of stay in phase 2 although this was not statistically significant (11.2 vs. 9.8 days in phase 1 and 2 respectively).   


    The addition of MALDI-TOF to an antimicrobial stewardship program led to improved patient outcomes by faster identification of organisms in positive blood cultures, improved time to optimal therapy, decreased antibiotic usage, and shorter length of stay.

    Hamid Razaki, PharmD1, Thien-Ly Doan, PharmD1, Henry Donaghy, MD2 and Scott Duong, MD3, (1)Pharmacy, Long Island Jewish Medical Center, New Hyde Park, NY, (2)Medicine - Infectious Diseases, Long Island Jewish Medical Center, Manhasset, NY, (3)Infectious Disease Diagnostics, North Shore-LIJ Laboratories, Lake Success, NY


    H. Razaki, None

    T. L. Doan, None

    H. Donaghy, None

    S. Duong, 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.