Bacterial Identification through Detection of Their Specific Proteins via MALDI-TOF MS

The study developed a protocol for bacterial recognition via charactering its specific proteins. Bacterial proteins were extracted from five model bacterial strains. MALDI-TOF mass spectrometry (MS) was utilized to analyze the bacterial proteins. Potential proteins (biomarkers) for the bacterial identification were screened. Twelve proteins specific to Escherichia coli, 5 to Staphylococcus aureus, 17 to Klebsiella pneumoniae, 28 to Salmonella enterica serovar Vellore, and 8 to Vibrio parahemolyticus were identified. The mass spectra for proteins of the analyzed bacterial strains exhibit excellent reproducibility (similarity scores ≥ 0.92, RSD ≤ 3.6%, n = 3). The determined detection limit (LOD) is 10⁴ CFU/mL for E. coli and V. parahemolyticus, and 10⁶ CFU/mL for S. aureus, K. pneumoniae, and S. Vellore. Sashimi muscle samples from salmon spiked with bacterial strains were tested to demonstrate the practical application of the present protocol. It holds potential of being a rapid and accurate identification tool for bacterial identification in foods.