Multiplex Detection of 24 Staphylococcal Enterotoxins in Culture Supernatant Using Liquid Chromatography Coupled to High-Resolution Mass Spectrometry.

Staphylococcal food poisoning outbreaks are caused by the ingestion of food contaminated with staphylococcal enterotoxins (SEs). Among the 27 SEs described in the literature to date, only a few can be detected using immuno-enzymatic-based methods that are strongly dependent on the availability of antibodies. Liquid chromatography, coupled to high-resolution mass spectrometry (LC-HRMS), has, therefore, been put forward as a relevant complementary method, but only for the detection of a limited number of enterotoxins.

Top-Down Mass Spectrometry for Trace Level Quantification of Staphylococcal Enterotoxin A Variants.

We addressed here the need for improved sensitivity of top-down mass spectrometry for identification, differentiation, and absolute quantification of sequence variants of SEA, a bacterial toxin produced by and regularly involved in food poisoning outbreaks (FPO). We combined immunoaffinity enrichment, a protein internal standard, and optimized acquisition conditions, either by full-scan high-resolution mass spectrometry (HRMS) or multiplex parallel reaction monitoring (PRM) mode. Deconvolution of full-scan HRMS signal and PRM detection of variant-specific fragment ions allowed confident identification of each SEA variant.

Quantitative Determination of Enterotoxins Types A to I and Variants in Dairy Food Products by Multiplex Immuno-LC-MS/MS.

Staphylococcal enterotoxins (SEs) are responsible for frequent food poisoning outbreaks worldwide. Specific identification of SEs is crucial for confirmation of food poisoning, tracking of the incriminated foods or food ingredients, and removal from the food chain. Here, we report on a new food testing protocol addressing the challenge of low abundance of SEs in contaminated food and high sequence heterogeneity.