Characterization of microbial mixtures by mass spectrometry.

Area of Science:

• Microbiology
• Analytical Chemistry
• Biotechnology

Background:

• Mass spectrometry (MS) applications in microbiology have grown substantially, driven by commercial platforms for clinical infection identification.
• The expansion of omics fields fuels novel MS-based research for characterizing organismal and environmental microbiomes.
• Characterizing microorganisms within complex mixtures remains a significant challenge for researchers and clinicians.

Purpose of the Study:

• To review recent advances in mass spectrometry (MS) techniques for addressing the challenge of microbial mixture characterization.
• To highlight MS hardware, ionization techniques, and bioinformatics approaches applicable to microbial analysis.

Main Methods:

• Review of sample preparation methods and protocols.
• Discussion of established (MALDI) and newer (API) ionization techniques for MS.
• Exploration of MS hardware, tandem MS, and diverse ion source/mass analyzer combinations.
• Highlighting chemometrics and bioinformatics for large-scale MS data analysis (metaproteomics, MS imaging).

Main Results:

• MALDI mass spectra of intact cells primarily yield biomarker information from highly expressed housekeeping proteins.
• API methods are suitable for small biomolecule analysis (e.g., phospholipids, lipopeptides), aiding species differentiation.
• Examples of microbial mixture characterization using various MS combinations are provided.

Conclusions:

• Recent MS advances offer powerful tools for analyzing complex microbial communities.
• Integration of diverse MS techniques and bioinformatics is crucial for microbial mixture characterization.
• MS applications in environmental and clinical microbiology, including polymicrobial culture analysis, are expanding.