Necrosis Research Paper

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The Flesh Fating Disease Necrosis is abnormal death of cells that are likely caused by disease or infection. Necrotizing fasciitis "the flesh eating disease" is caused by several bacteria (mixed flora, aerobic and anaerobic), the most common and deadly is Streptococcus pyogenes (S. pyogenes) or group A streptococcus. Characteristics are Gram positive, nonmotile, nonsporeforming, beta hemolytic catalase negative, cocci that are spherical bacterium that appears in chain-like formations. S. pyogenes are considered a facultative anaerobic bacterium; it can grow in the presence or absence of oxygen. Growth is stimulated by incubating in an environment with increased carbon dioxide. Type I caused by anaerobic bacteria with or without the presence…show more content…
It begins with a harmless cut in the skin and spreads rapidly into nearby tissue. When streptococci on the skin are introduced to the cut, strains of group A release enzymes and toxins that greatly increase invasiveness and virulence. Invasive bacteria are pathogens that can invade parts of the body where bacteria are not normally present, such as the bloodstream, and soft tissues like muscle or fat. Virulence is the degree of pathogenicity determined by its ability to establish itself in a host and survive the host defense. Virulence factors of group A streptococci include (1) M protein and lipoteichoic acid for attachment; (2) a hyaluronic acid capsule that inhibits phagocytosis; (3) other extracellular products, such as pyrogenic (erythrogenic) toxin, which causes the rash of scarlet fever; and (4) streptokinase, streptodornase (DNase B), and streptolysins. Some strains are nephritogenic. Immune-mediated sequelae do not reflect dissemination of bacteria. Nongroup A strains have no defined virulence factors. Antibody to M protein gives type-specific immunity to group A streptococci. Antibody to erythrogenic toxin prevents the rash of scarlet fever. Immune mechanisms are important in the pathogenesis of acute rheumatic fever. S. pyogenes produce several virulence factors that lend to its pathogenicity, or disease-causing capabilities. It contains a capsule that helps allow the bacteria to disguise it from getting engulfed by white blood cells (phagocytosis). It also contains proteins on its cell wall that allows it to adhere to epithelial cells, which allows it to produce disease. S. pyogenes also produces several enzymes that give the bacteria the ability to destroy tissue and spread. The enzymes digest the connective tissue in the skin. Lastly, it produces a wide variety of toxins that can produce
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