Intact Staphylococcus Enterotoxin SEB from Culture Supernatant Detected by MALDI-TOF Mass Spectrometry

Area of Science:

• Microbiology
• Analytical Chemistry
• Food Safety

Background:

• Routine pathogen identification uses MALDI-TOF MS on intracellular proteins.
• Extracellular pathogen factors, such as toxins, are crucial for virulence and food safety.
• Current methods for detecting extracellular toxins can be complex and time-consuming.

Purpose of the Study:

• To evaluate matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identifying extracellular pathogen factors.
• To develop a protocol for detecting Staphylococcus aureus enterotoxins (SEs) in their intact form.
• To assess the stability of SEs after common food processing treatments.

Main Methods:

• Cultivation of Staphylococcus aureus and collection of secreted proteins via methanol-chloroform precipitation.
• Analysis of secreted proteins using MALDI-TOF MS.
• Identification of detected peaks using reference standards and amino acid sequence analysis.
• Detection of SEs (SEB, SEA, SEC) in intact forms.

Main Results:

• A peak at m/z 28,250 was identified as intact Staphylococcus aureus enterotoxin type B (SEB).
• SEB was detected in its intact form even after pasteurization and cooking.
• The protocol successfully identified other SEs, including SEA (m/z 27,032) and SEC (m/z 27,629).

Conclusions:

• A simple sample preparation method allows for the easy identification of extracellular pathogen factors using MALDI-TOF MS.
• This technique represents a promising next-generation application for detecting intact SEs.
• MALDI-TOF MS offers a novel approach for pathogen toxin detection in food safety and clinical microbiology.