Staphylococcus aureus

Staphylococcus aureus life history and features: Staphylococcus aureus is a Gram-positive bacteria usually found in 15-40% of nasal cavity and healthy human skin, but it can also survive in various places in the body. This bacterium spreads among humans or people by directly contacting them. Colonies of S. aureus appear in pairs, chains, or clusters. Staphylococcus aureus is not a living thing in a specific place in the world, but it is a general health problem, especially in the food processing industry.

Staphylococcus aureus Staphylococcus aureus is generally found in the skin and nose of healthy people (about one-third of a person). Most people who have staphylococci in the skin and nose are not adversely affected and are described as "colonization". Methicillin-resistant Staphylococcus aureus (MRSA) is a special Staphylococcus that has become unresponsive to many commonly used antibiotics such as penicillin. These bacteria invade the body through the skin due to incision, pain or surgical incision, sometimes infection (such as impetigo, vap, abscess or infected wound). This situation is most likely to happen to people who are already sick, but it can also happen to healthy people in the area.

Treatment of infection by Staphylococcus aureus revolutionized in the 1940's by the introduction of antibiotic penicillin. However, most S. aureus strains are currently resistant to penicillin. Staphylococcus aureus decomposes penicillin and produces a substance called beta-lactamase which destroys its antibacterial activity. In the early 1960s, a new penicillin antibiotic called methicillin was developed. Methicillin is not degraded by β-lactamase and can therefore be used to treat infections caused by Staphylococcus aureus strain producing S. aureus strains. Later, methicillin is replaced by a better penicillin antibiotic, which is not affected by beta - lactamase like fluxacillin. Unfortunately, some Methicillin-resistant Staphylococcus aureus strains called MRSA (Johnson, 2007) immediately after the introduction of methicillin.

Staphylokinase is an enzyme produced by Staphylococcus aureus. When staphylokinase is released from Staphylococcus aureus and targeted to neutrophils, alpha-alpha-defensin is produced which is then neutralized by S. aureus. This results in inhibition of the bactericidal action of defensins by activation of plasmin, and staphylokinase increases bacterial infection process. Plasminogen is tightly regulated and is part of a fibrinolytic mechanism that coats fibrin when blood vessels are damaged. Staphylococcus aureus converts plasminogen to fibrin with the help of fibrin as a cofactor. Staphylokinase is encoded by the Sak gene and is regulated by the agr gene. Its structure has a central α-helix and 5β plate stock. . When neutrophils bind to the central alpha link, a conformational change is induced. Therefore, plasminogen is converted to plasmin. Several sites that bind to neutrophils are found in staphylokinase.