Effects of Staphylococcus aureus hemolysin toxins on blood cells and association with skin and soft tissue infections

Staphylococcus aureus (S. aureus) is gram positive, catalase positive cocci which belongs to the family of Staphylococcaceae and is long known as clinical and foodborne pathogen. The emergence of multidrug resistance strain of S. aureus which is methicillin resistant S. aureus (MRSA) challenges the health care system because it can cause wide variety of hospital and community acquired skin and soft tissue infections which are difficult to treat. The virulence of S. aureus is because of different factors which includes toxins, enzymes and superantigens. S. aureus produce variety of exotoxins, enterotoxins and exfoliative toxins which contributes to the virulence of S. aureus. Hemolysin toxins produce by S. aureus strains are associated with different skin and soft tissue infections (SSTIs) and can cause the lysis of RBCs. Hemolysins are regulated by accessory gene regulator (agr) and is required for the enhanced expression of virulence factors secreted by S. aureus. Hemolysins have leucolytic activity and can help in iron scavenging from host. The most important toxin is alpha hemolysin which can induce the apoptosis and cause the lysis of epithelial cells, erythrocytes and keratinocytes. Human immune cells are affected by beta hemolysin and gamma hemolysin is a biocomponent toxin. Delta hemolysin is low molecular weight exotoxin which belongs to the class of phenol soluble modulins. Keywords: MRSA, Exotoxins, Hemolysins, SSTIs