This article reviews the literature regarding the structure and function of two types of exotoxins expressed by Staphylococcus aureus, pyrogenic toxin superantigens (PTSAgs) and hemolysins. The molecular basis of PTSAg toxicity is presented in the context of two diseases known to be caused by these exotoxins: toxic shock syndrome and staphylococcal food poisoning. The family of staphylococcal P...

The inflammasomes are intracellular protein complexes that play an important role in innate immune sensing. Activation of inflammasomes leads to activation of caspase-1 and maturation and secretion of the pro-inflammatory cytokines interleukin (IL)-1β and IL-18. In certain myeloid cells, this activation can also lead to an inflammatory cell death (pyroptosis). Inflammasome sensor proteins have ...

Nitric oxide (NO) is believed to play an important role in sepsis-related hypotension. We examined the effects of two pore-forming bacterial exotoxins, Escherichia coli hemolysin and Staphylococcus aureus alpha-toxin, on NO formation in cultured porcine pulmonary artery endothelial cells. NO was quantified using a difference-spectrophotometric method based on the rapid and stoichiometric reacti...

Group A streptococcal pyrogenic exotoxins (SPE) types A, B, and C are potent nonspecific lymphocyte mitogens. The mitogenicity of these exotoxins was inhibited by gangliosides and sialic acid, whereas concanavalin A was unaffected. The capacity of both concanavalin A and SPE-A to stimulate lymphocytes was suppressed by alpha-methyl-D-mannopyranoside. Galactose reduced the activity of SPE-C. The...

BACKGROUND The pathogenicity of staphylococcus aureus is dependent largely upon its ability to secrete a number of virulence factors, therefore, anti-virulence strategy to combat S. aureus-mediated infections is now gaining great interest. It is widely recognized that some plant essential oils could affect the production of staphylococcal exotoxins when used at subinhibitory concentrations. Per...

Staphylococcal scalded-skin syndrome is an exfoliative dermatitis characterized by the separation of the epidermis at the stratum granulosum. This disruption is mediated by one of two Staphylococcus aureus exotoxins, exfoliative toxins A and B (ETA and ETB). Both ETA and ETB have been reported to be bacterial superantigens. A controversy exists, however, as other data indicate that these exotox...

The recent discovery of the mode of interaction between a group of microbial proteins known as superantigens and the immune system has opened a wide area of investigation into the possible role of these molecules in human diseases. Superantigens produced by certain viruses and bacteria, including Mycoplasma species, are either secreted or membrane-bound proteins. A unique feature of these prote...

Bacillus cereus is mainly known as a human food-borne opportunistic pathogen. Here, we used biological assays and HPLC to investigate the ability of B. cereus to produce insecticidal exotoxins during the stationary growth phase. None of the 575 B. cereus strains screened produced detectable levels of beta-exotoxin I, a small, heat-stable insecticidal nucleotide analogue. However, six out of a s...