Streptococcus group A

Streptococcus is another kind of common bacteria of pyogenic coccus, which is widely existed in nature and human and animal excrement and nasopharynx of healthy people, causing various suppurative inflammation, scarlet fever, erysipelas, neonatal septicemia, meningitis, puerperal fever and streptococcal allergic diseases.

According to the structure of antigens, streptococci are divided into 18 groups, such as A, B, C and D. In each group, due to the different properties of surface antigens, they are divided into several subgroups.

Group A streptococcus has strong invasiveness, which can produce a variety of enzymes and exotoxins, including M protein that is the protein component in the cell wall of streptococcus, with anti-phagocytic and anti-phagocytic effect in the cell; Lipophosphoric acid (LTA) is associated with bacterial adhesion to the host cell surface. Most LAT is located between the cell membrane and peptidoglycan, which extends to the bacterial cell surface through the peptide holes. LAT binding sites are found on human oral mucosa, skin epithelial cells, blood cells and other cell membranes. Hyaluronidaes (Hyaluronidaes) can decompose hyaluronic acid between cells, making it easy for bacteria to spread in tissues. Streptokinase (SK), also known as streptococcus soluble fiber protease (Streptococcal fibrinolysin), is a kind of kinase, activating blood plasma protease in the original. Plasma can dissolve blood clots or prevent plasma coagulation, which is conducive to the spread of bacteria in the organization. About 50 minutes refractory, 100 °C heat remain active. The antibody of streptokinase can neutralize the activity of this enzyme. Streptodonase is also known as Streptococcal deoxyribonuclease. It is mainly produced by group A, C and G streptococci. This enzyme breaks down the highly viscous DNA in the viscous pus, making the pus thin and easy to diffuse. The corresponding antibodies produced have the activity of neutralizing the enzyme. Skin test with streptokinase and streptase is used as a method to measure cellular immunity. Streptolysin can dissolve red blood cells, kill white blood cells and poison the heart, mainly including "O" and "S".