1879. Infectious Diseases Consultation for Positive Blood Cultures Before and After the Implementation of MALDI-TOF
Session: Poster Abstract Session: Antibiotic Stewardship: Diagnostics
Saturday, October 29, 2016
Room: Poster Hall
  • IDweek_poster_draft10102016.pdf (5.8 MB)
  • Background: Matrix-assisted laser desorption ionization time-of-flight mass spectroscopy (MALDI-TOF) offers a rapid, accurate, and cost-effective method for bacterial identification and is being widely adopted by clinical microbiology laboratories. Little is known about the effect of its implementation on clinical infectious diseases (ID) consult services.

    Methods: A retrospective, quasi-experimental design was used. All positive blood cultures at two academic medical centers from March 2013 to October 2014 (12 months prior to and 6 months after implementation of MALDI) were identified and narrowed to 3,192 unique episodes of which 1,000 charts were reviewed. Interrupted time series analysis compared ID consult rates to a renal consult control group. Secondary analyses explored differences in patients who received consults versus those who did not.

    Results: ID consult patients were more likely than non-consults to be younger (59 vs 64y, p<0.001), male (60 vs 44%, p<0.001), and white (34 vs 23%, p<0.001). Most consults were for a positive blood culture (71%); but surgical services consulted at nearly double the rate of medical services (65 vs 38%, p<0.001). Polymicrobial bacteremia elicited a higher rate than monomicrobial (21 vs 11%, p<0.001). Length of stay was longer in patients receiving ID consults (20.4 vs 8.5 days, p<0.001); however, mortality did not differ significantly between the two groups (11.2 vs 12.4%, p=0.540). Consults more often had primary bacteremia (40.6 vs 14.5%, p<0.000), osteomyelitis (6.2 vs 1.7%, p<0.001), or endocarditis (6.2 vs 0.2%, p<0.001), whereas non-consults were more likely to be deemed a contaminant (37.3 vs 12.1%, p=0.003) or have a urinary (17.8 vs 6.4%, p=0.024) or GI source (8.9 vs 6.7%, p=0.008). There were no significant differences between patients evaluated in the pre- and post-intervention groups. Interrupted time series analysis revealed no significant difference in trends in ID consult rate after the implementation of MALDI-TOF (p=0.268) and no difference compared to the control group (p=0.968).

    Conclusion: The rate of ID consults (versus control) did not change after the implementation of MALDI-TOF; however, differences between patients with and without ID consults warrant further exploration.

    Sharon Tsay, MD1, Kevin Alby, PhD2, Todd Barton, MD1 and Valerie Cluzet, MD1, (1)Infectious Diseases, Hospital of the University of Pennsylvania, Philadelphia, PA, (2)Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA


    S. Tsay, None

    K. Alby, None

    T. Barton, None

    V. Cluzet, None

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