Update on molecular diversity and multipathogenicity of staphylococcal superantigen toxins

Abstract

Staphylococcal superantigen (SAg) toxins are the most notable virulence factors associated with Staphylococcus aureus, which is a pathogen associated with serious community and hospital acquired infections in humans and various diseases in animals. Recently, SAg toxins have become a superfamily with 29 types, including staphylococcal enterotoxins (SEs) with emetic activity, SE-like toxins (SEls) that do not induce emesis in primate models or have yet not been tested, and toxic shock syndrome toxin-1 (TSST-1). SEs and SEls can be subdivided into classical types (SEA to SEE) and novel types (SEG to SElY, SE01, SE02, SEl26 and SEl27). The genes of SAg toxins are located in diverse accessory genetic elements and share certain structural and biological properties. SAg toxins are heat-stable proteins that exhibit pyrogenicity, superantigenicity and capacity to induce lethal hypersensitivity to endotoxin in humans and animals. They have multiple pathogenicities that can interfere with normal immune function of host, increase the chances of survival and transmission of pathogenic bacteria in host, consequently contribute to the occurrence and development of various infections, persistent infections or food poisoning. This review focuses on the following aspects of SAg toxins: (1) superfamily members of classic and novelty discovered staphylococcal SAgs; (2) diversity of gene locations and molecular structural characteristics; (3) biological characteristics and activities; (4) multi-pathogenicity of SAgs in animal and human diseases, including bovine mastitis, swine sepsis, abscesses and skin edema in pig, arthritis and septicemia in poultry, and nosocomial infections and food-borne diseases in humans.

Genome Evolution of Invasive Methicillin-Resistant Staphylococcus aureus in the Americas

“…We next sought to investigate the phylogenetic distribution of genes that encode superantigens. Superantigens comprise a family of potent immunostimulatory exotoxins that modulate the immune system by stimulating dysregulated T-cell proliferation ( 23 , 24 ) and are known to contribute to a variety of staphylococcal diseases ( 23 , 24 ), including bloodstream infections ( 25 ). Of the 29 known superantigen types ( 23 , 24 ), we detected a total of 10 superantigens in the American MRSA population that were differentially distributed between the two dominant lineages ( Fig.…”

Staphylococcal Enterotoxin Genes in Coagulase-Negative Staphylococci—Stability, Expression, and Genomic Context

“…Isolates of CoNS in which enterotoxin genes in an unstable form and low copy numbers are present are not capable of producing enterotoxins, even under optimal laboratory conditions. The enterotoxigenicity of staphylococci contributed to a number of human and animal diseases, including organ and systemic disorders [ 28 , 29 ]. However, to date, all these cases were only associated with SE-producing S. aureus .…”

Hyperimmune Targeting Staphylococcal Toxins Effectively Protect Against USA 300 MRSA Infection in Mouse Bacteremia and Pneumonia Models

“…There are more than 29 types of S. aureus superantigens (SAgs) in various strains, including staphylococcal enterotoxins (SEs), staphylococcal enterotoxin-like toxins (SEls), and toxic shock syndrome toxin-1 (TSST-1). Most virulent S. aureus isolates produce at least one or more SAgs ( 56 ). SAgs are not only important for toxic shock syndrome but also play a role in sepsis and possibly other S. aureus invasive diseases ( 57 , 58 ).…”