MSACL 2023 Abstract

Comparison of a Novel Lipid-based MALDI-TOF MS Technique to Two FDA-cleared Direct from Blood Culture Diagnostics

Richard D. Smith1, 2, Robert K. Ernst#1, and J. Kristie Johnson#2
1 Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201 USA 2 Department of Pathology, School of Medicine, University of Maryland, Baltimore, MD 21201 USA

Richard Smith (Presenter) University of Maryland

Relevant Financial Disclosures (within past 24 months, reported on Nov 30, 2022) No relevant financial relationship(s) to disclose. Discussing Products? NO, presenter will NOT present educational content related to products/services of the ineligible company(ies) listed above. Conflict mitigation NOT REQUIRED.

Background:
Managing Bloodstream Infections requires fast and accurate diagnostics. Current diagnostic methods for identification from positive blood culture require 24-hour subculture, potentially delaying time to appropriate therapy. In this study, we developed a direct-from-specimen, lipid-based MALDI-TOF MS platform, Fast Lipid Analysis Technique (FLAT), and compared it to several FDA-cleared, direct from blood culture diagnostic platforms.

Methods:
Positive blood cultures were collected (n=301) from September 2021 to August 2022 at the University of Maryland Medical Center. Platforms compared were FLAT, BioFire® BCID2, and Rapid Sepsityper®.

Results:
For monomicrobial cultures, lipid-based MS with FLAT identified 81.0% (85/105) of Gram-positives, 94.9% (149/157) of Gram-negatives, and 63.6% (7/11) of yeast. BioFire® BCID2 identified 85.7% (90/105) of Gram-positives, 89.8% (141/157) of Gram-negatives, and 90.9% (10/11) of yeast. Rapid Sepsityper® identified of 61.0% (64/105) of Gram-positives, 89.8% (141/157) of Gram-negatives, and 45.5% (5/11) of yeast. For polymicrobial cultures, FLAT had 71.4% (20/28) partial identifications and 28.6% (8/28) complete identifications. BioFire® BCID2 had 7.1% (2/28) partial identifications and 92.9% (26/28) complete. Sepsityper® 82.1% (23/28) and 10.7% (3/28) had partial and complete identifications, respectively, and 7.1% (2/28) without identifications, Time-to-results for BioFire®, Rapid Sepsityper®, were 60, 65, and 35 minutes, respectively. Hands-on time was 10, 5, and 25 minutes, respectively.

Conclusions:
Performance of these platforms can reduce time-to-results and may help effectively treat bloodstream infections faster. FLAT outperformed the current FDA-cleared, direct-from-blood culture MS method, Sepsityper®. Furthermore, FLAT had comparable result to the molecular assay BioFire® BCID2; however, cost is an important factor to be considered as lipid-based MALDI-TOF MS is much less expensive than molecular methods.