Direct Identification From Positive Blood Cultures Shows 95.6% Agreement
A published study found that FASTINOV sample preparation supported reliable MALDI-TOF identification directly from positive blood cultures, creating a common starting point for rapid ID and AST workflows.
Rapid antimicrobial susceptibility testing is most useful when the microorganism is also identified quickly. A study published in the European Journal of Clinical Microbiology & Infectious Diseases evaluated whether the bacterial suspension produced by FASTINOV sample preparation could be used for MALDI-TOF MS identification directly from positive blood cultures.
Study design
The researchers analysed 364 positive blood cultures: 177 containing Gram-positive cocci and 187 containing Gram-negative bacilli. Identification obtained after FASTINOV sample preparation was compared with MALDI-TOF identification from colonies grown by next-day subculture, which served as the reference method.
High agreement across Gram-positive and Gram-negative bacteria
The direct method produced an identification in 348 of 364 samples, for an overall agreement of 95.6% with the reference workflow. Agreement was 94.9% among Gram-positive isolates and 96.3% among Gram-negative isolates. Importantly, the study reported no misidentifications: the 16 remaining samples produced no identification rather than an incorrect result.
Across 364 positive blood cultures, MALDI-TOF identification after FASTINOV sample preparation achieved 95.6% overall agreement with next-day colony identification, with no observed misidentifications.
One preparation step, two downstream paths
The preparation method removes blood cells and debris while recovering a concentrated bacterial suspension. In the study workflow, the resulting material supported MALDI-TOF identification and could also be used for FASTINOV’s rapid phenotypic AST. This creates the possibility of running rapid identification and susceptibility testing in parallel from the same positive blood culture preparation.
The authors reported 3–5 minutes of hands-on preparation time and a maximum of two hours for the combined ID-and-AST workflow described in the study. The identification findings should be understood as performance of the complete sample-preparation-plus-MALDI-TOF workflow, not as a standalone AST result.
What this means for the laboratory
Species-level identification is important for selecting an appropriate AST panel and interpreting species-specific breakpoints. A clean preparation that can feed both ID and AST may reduce repeated sample handling and help laboratories move more quickly from a positive blood culture to actionable microbiology results.
Read the study
Cruz S, Abreu D, Gomes R, et al. “An improved protocol for bacteria identification by MALDI-TOF MS directly from positive blood cultures.†European Journal of Clinical Microbiology & Infectious Diseases. 2024;43:605–610. https://doi.org/10.1007/s10096-023-04725-3