Streptococcus pyogenes, also known as impetigo, strep throat, etc., is a flesh eating bacteria, that if left untreated, can lead to very serious symptoms. This bacterium is responsible for a wide array of infections. It can cause a sore throat, that is caused by, fever, enlarged tonsils, and sensitive cervical lymph nodes. Scarlet fever, as well as impetigo, and pneumonia are also caused by this bacterium. The less common infections consist of septicaemia, mastitis, endocarditis, sepsis, cellulitis, meningitis, erysipelas, myositis, otitis media, osteomyelitis, septic arthritis, pericarditis, and neonatal.
a. S. pyogenes on blood agar b. S. pyogenes with Pappenheim stain
S. pyogenes grows in streptococcus …show more content…
pyogenes has several virulence factors that can help evade the immune system and spread into deeper tissues. One of the most important virulence factors is the fimbriae. The fimbriae contains a M-protein that blocks the binding site. This inhibits phagocytosis from the host. The M-protein also affects the heart because they contain antigenic molecules that cause autoimmune rheumatic carditis(rheumatic fever). The bacteria produces many exotoxins, such as Streptolysin O, Streptolysin S, Streptococcal pyogenic exotoxin A, and Streptococcal pyogenic exotoxin C. These exotoxins create the beta-hemolytic property on blood agar, and also cause irritation (ex. rash). S. pyogenes also produces many different enzymes. Streptokinase activates plasminogen, which then turns to plasmin. The enzyme breaks down blood also, helping the beta-hemolytic trait. Hyaluronidase is another enzyme, that breaks down hyaluronic acid. The acid is an important part of human connective tissue. Very few S. pyogenes can produce this enzyme but, do not need this enzyme to cause lesions. The bacteria also secretes streptodornase. This enzyme helps the bacteria from becoming trapped neutrophil traps by degrading the DNA of the neutrophil. The neutrophil, also, is affected by C5a peptidase. This enzyme stops the C5 chemotaxin produced by the neutrophil. This helps the bacteria spread by stopping the immune systems attempt to stop colonization. The last enzyme produced by S. pyogenes, Streptococcus chemokine …show more content…
pyogenes is a very successful bacteria that can not only cause large infections but, can also evade the body’s immune system. Diseases associated with this bacteria can affect the blood, respiratory tract, or the skin. S. pyogenes mostly affects the respiratory tract and skin. Although, the skin cannot become infected from the respiratory tract and vice versa. The bacteria is the leading cause of many respiratory infections, like pharyngitis, also called, strep throat. It can also cause sinusitis, pneumonia, otitis in the respiratory tract. There are two types of skin infections: deep and superficial. The deep infection is usually cellulitis. The superficial infection is usually impetigo. If the S. pyogenes becomes invasive, it can cause bone or joint infections, meningitis, necrotizing fasciitis, and endocarditis. If the infection is left for too long the infection can cause a lot of problems like, rheumatic fever or glomerulonephritis. Only 1-3% of infected usually develop the more advanced infections. When the toxins are circulating through the blood, Scarlet fever or streptococcal toxic shock syndrome, can take place. S. pyogenes’ membrane contains similar antigens to the human cardiac, smooth, and neuronal tissues. This results in suppressed immune response from the