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Scanning Electron Microscope: A New Potential Tool to Replace Gram Staining for Microbe Identification in Blood
Gabriel Haddad1,2, Sara Bellali1, Tatsuki Takakura3
1Institut Hospitalo-Universitaire Méditerranée Infection 19-21 Boulevard Jean Moulin, 13005 Marseille, France.
Microorganisms
|June 2, 2021
Summary
A new scanning electron microscope (SEM) method rapidly identifies microbes in positive blood cultures within an hour, improving diagnosis of sepsis and bloodstream infections. This technique offers faster results than traditional methods, aiding clinical microbiology labs.
Area of Science:
- Microbiology
- Medical Diagnostics
- Microscopy
Background:
- Blood cultures are standard for diagnosing sepsis and bloodstream infections.
- Current methods have long turnaround times for microbe identification.
- Gram staining is the established preliminary identification method.
Purpose of the Study:
- To develop and evaluate a rapid scanning electron microscope (SEM) strategy for direct microbe identification from blood cultures.
- To compare the performance of SEM with Gram staining for preliminary identification.
- To assess SEM's potential to reduce diagnostic turnaround times in clinical microbiology.
Main Methods:
- Optimized sample preparation for simultaneous analysis of twelve blood cultures.
- Utilized a tabletop scanning electron microscope (SEM) for direct imaging and identification.
- Blindly tested 1075 blood cultures, comparing SEM results to Gram staining and MALDI-TOF/MS.
Main Results:
- SEM successfully identified bacteria and yeasts, often to the genus level.
- Microbe identification was achieved within one hour of a positive blood culture detection.
- The SEM method demonstrated advantages in speed, cost, and data traceability compared to Gram staining.
Conclusions:
- Scanning electron microscopy (SEM) offers a rapid and effective method for preliminary microbe identification directly from positive blood cultures.
- This SEM strategy has the potential to significantly accelerate the diagnosis of infectious diseases.
- Further development towards an automated SEM assay could revolutionize urgent microbiological diagnostics.
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