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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: Food compounds inhibit Staphylococcus aureus bacteria and the toxicity of Staphylococcus Enterotoxin A (SEA) associated with atopic dermatitis

Authors
item Rasooly, Reuven
item Friedman, Mendel

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: July 29, 2011
Publication Date: February 1, 2012
Citation: Rasooly, R., Friedman, M. 2012. Food compounds inhibit Staphylococcus aureus bacteria and the toxicity of Staphylococcus Enterotoxin A (SEA) associated with atopic dermatitis. In: Esparza-Gordillo, J., editor. Atopic Dermatitis-Disease Etiology and Clinical Management. Croatia: Intech Europe. p. 387-404

Interpretive Summary: This chapter was prepared in response to an invitation of the editor of a book entitled “Atopic Dermatitis” to be published by In Tech Online Book Publishers. It summarizes our studies on the inactivation of the virulent Staphylococcus aureus bacteria and the staphylococcus enteroxin produced by these bacteria which are reported to be associated with atopic dermatitis and other diseases in humans. Staphylococcus. aureus is a major bacterial pathogen that develops resistance to medical antibiotics. It has been reported to cause clinical infections and contamination of a broad variety of foods, including canned mushroom, breaded chicken products, cheese, and raw milk as well on handles of shopping carts causing 185 000 cases of foodborne illnesses in the United States each year. S. aureus bacteria are present on the skin patients with atopic dermatitis. Many strains of S. aureus isolated from atopic skin lesions produce enterotoxins with superantigenic properties. S. aureus produces the virulent staphylococcal enterotoxin A, a single chain protein which consists of 233 amino acid residues. It has been estimated that the toxin that is secreted by the bacteria is associated with 78% of staphylococcal outbreaks. Our studies show that naturally occurring edible apple phenolic and olive compounds can both inactivate S. aureus bacteria and reduce the biological/toxicological properties of the toxin produced by these bacteria and that the food dye Phloxin B inhibits the release of SEA from the pathogens. The described studies are part of broader effort whose specific objective is to transform toxic proteins to nontoxic, digestible proteins in foods.

Technical Abstract: Atopic dermatitis or eczema is characterized by skin rashes and itching is an inflammatory disease that affects 10-20% of children and 1-3% of adults. Staphylococcus aureus bacteria are present on the skin of nearly all patients with atopic dermatitis. Antibiotics that suppress colonization of S. aureus are reported to alleviate the severity of this skin disease. Many strains of S. aureus isolated from atopic skin lesions produce enterotoxins with superantigenic properties. Functional enterotoxins bind to the alpha-helical regions of the major histocompatibility complex (MHC) class II molecules outside the peptide binding groove of the antigen presenting cells (APC), and also to the variable region (Vß) on T-cell receptors. The toxin then forms a bridge between T cells and APC. This event then initiates the proliferation of a large number (~20%) of T cells which induce the release of cytokines. At high concentrations, cytokines are involved in the etiology of several known human and animal diseases. These include atopic dermatitis and rheumatoid arthritis in humans and mastitis in dairy cows. SEA is a representative superantigen considered to be an aggravating factor in atopic dermatitis. It has been previously reported that human consumption of apples alleviated symptoms associated with atopic dermatitis. In this chapter we summarize results from ongoing studies on (a) inactivation of antibiotic-resistant and non-resistant toxin-producing S. aureus bacteria by food ingredients; (b) inhibition toxin production by S. aureus; and (c) reduction of the biological activity of SEA by apple and olive compounds. Possible mechanisms that govern these cellular and molecular events are discussed. The results suggest that dietary plant compounds have the potential to reduce superantigenic manifestations induced by SEA, possibly including atopic dermatitis symptoms.

Last Modified: 12/20/2014
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