Basis of Virulence in Enterotoxin-Mediated Staphylococcal Food Poisoning

Abstract

The Staphylococcus aureus enterotoxins are a superfamily of secreted virulence factors that share structural and functional similarities and possess potent superantigenic activity causing disruptions in adaptive immunity. The enterotoxins can be separated into two groups; the classical (SEA-SEE) and the newer (SEG-SElY and counting) enterotoxin groups. Many members from both these groups contribute to the pathogenesis of several serious human diseases, including toxic shock syndrome, pneumonia, and sepsis-related infections. Additionally, many members demonstrate emetic activity and are frequently responsible for food poisoning outbreaks. Due to their robust tolerance to denaturing, the enterotoxins retain activity in food contaminated previously with S. aureus. The genes encoding the enterotoxins are found mostly on a variety of different mobile genetic elements. Therefore, the presence of enterotoxins can vary widely among different S. aureus isolates. Additionally, the enterotoxins are regulated by multiple, and often overlapping, regulatory pathways, which are influenced by environmental factors. In this review, we also will focus on the newer enterotoxins (SEG-SElY), which matter for the role of S. aureus as an enteropathogen, and summarize our current knowledge on their prevalence in recent food poisoning outbreaks. Finally, we will review the current literature regarding the key elements that govern the complex regulation of enterotoxins, the molecular mechanisms underlying their enterotoxigenic, superantigenic, and immunomodulatory functions, and discuss how these activities may collectively contribute to the overall manifestation of staphylococcal food poisoning.

Staphylococcal enterotoxin U promotes proinflammatory activity of macrophage via up‐regulation of allograft inflammatory factor 1 expression

“…SEs are a series of virulence factors harboring potential super‐antigenic activity causing disruptions in S . aureus infections (Fisher et al, ). Although these proteins stimulated nonspecific T cell proliferation, the effects of SEs on proinflammatory activity of macrophage were unknown.…”

“…Macrophages are involved in several diseases depending on the microenvironment and activation state of the cells. SEs are a series of virulence factors harboring potential super-antigenic activity causing disruptions in S. aureus infections (Fisher et al, 2018).…”

“…aureus can produce an impressive catalog of toxins. These proteins were reported to be associated with a multitude of diseases (Fisher, Otto, & Cheung, ). Perhaps the most notable toxins are staphylococcal enterotoxins (SEs), a series of potential super‐antigens causing unregulated activation of immune responses during S .…”

“…S. aureus can produce an impressive catalog of toxins. These proteins were reported to be associated with a multitude of diseases (Fisher, Otto, & Cheung, 2018 immune responses during S. aureus infections (Fraser & Proft, 2008;Spaulding et al, 2013). Thus, SEs are shown to be involved in pneumonia, toxic shock syndrome, sepsis-related infections and food poisoning (Balaban & Rasooly, 2000;Langley, Patel, Jackson, Clow, & Fraser, 2010;Lappin & Ferguson, 2009;Lowy, 2003;Ortega, Abriouel, Lucas, & Gálvez, 2010).…”

Prevalence of Staphylococcal Superantigens and their association among bacteremic and Infective Endocarditis patients in Egypt

“…S. aureus strains secrete up to 23 of at least 24 serologically distinct SAgs including TSST-1, SEs and the SE-like (SE-l) [8,14,15]. These SAgs have the distinctive capability to concurrently bind both major histocompatability complex and the T-cell receptor, exerting immune response 20% greater than that of ordinary antigens [16, 17]. This immune response is associated with a substantial discharge of various inflammatory cytokines and several interleukins which could have a direct cytotoxic effect on the endothelial cells [7].…”