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United States Department of Agriculture

Agricultural Research Service

Research Project: Technologies for Detecting and Determining the Bioavailability of Bacterial Toxins

Location: Foodborne Toxin Detection and Prevention

Title: Techniques for rapid detection and quantification of active foodborne Staphylococcus Enterotoxin(Abstract)

Authors
item Hernlem, Bradley
item Rasooly, Reuven

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 5, 2012
Publication Date: June 23, 2012
Citation: Hernlem, B.J., Rasooly, R. 2012. Techniques for rapid detection and quantification of active foodborne Staphylococcus Enterotoxin(Abstract). Meeting Abstract. Poster no. B266.

Technical Abstract: Background: Staphylococcus aureus is an important bacterial pathogen and causative agent of foodborne illnesses.Staphylococcal enterotoxins(SEs)produced by this organism act upon the gastrointestinal tract and generate a superantigen immune response in low concentrations. Recent S. aureus foodborne outbreaks have primarily been associated with SE type A (SEA) and illustrate the need for improved rapid and sensitive methods to detect active SEA in food. Methods: Splenocytes were isolated from mice and further sub-divided by positive selection(Dynabeads® Mouse CD4)to isolate CD4+ T cells. Immunophenotype analysis and cytometric bead array techniques were used to detect and quantify expression of cell surface markers and cytokine response to exposure to SEA and SEB. Flow cytometric analysis and cell sorting was performed using a FACSVantage SE modified with a 100 mW 491 nm Cobolt CalypsoTM DPSS laser and also employing a 40 mW 640 nm Coherent CubeTM laser and a 405 nm Power Technology laser module operated at 125mW. Results: Positive selected mouse CD4+ T cells exhibit a response to SEA exposure, expressing CD154 in as little as 6 hrs. Cytokine response is observed within 24 hours. Both responses are time and dose dependent. SEA was detected in spiked samples of milk and other food matrices. Conclusions: Monitoring cell surface markers and cytokine response in mouse CD4+ T cells provides convenient and rapid method to detect and quantify active SEA.

Last Modified: 7/28/2014
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