What are the virulence factors of Streptococcus pyogenes?
What are the virulence factors of Streptococcus pyogenes?
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 …
What is Lipoteichoic acid function?
Lipoteichoic acid (LTA) is a surface-associated adhesion amphiphile from Gram-positive bacteria and regulator of autolytic wall enzymes (muramidases). It is released from the bacterial cells mainly after bacteriolysis induced by lysozyme, cationic peptides from leucocytes, or beta-lactam antibiotics.
What does Streptococcus pyogenes secrete?
Streptococcus pyogenes secretes two well-known hemolysins, streptolysin O and streptolysin S, which have effects on a variety of cell types.
What is the causative agent of Streptococcus pyogenes?
aureus is the predominant causative agent; myositis due to S. pyogenes is rare. In contrast, non-purulent soft tissue infection due to S. pyogenes is common in patients with necrotizing fasciitis, myonecrosis, and StrepTSS.
What type of cell is Streptococcus?
Streptococci are coccoid bacterial cells microscopically, and stain purple (Gram-positive) when Gram staining technique is applied. They are nonmotile and non-spore forming. These cocci measure between 0.5 and 2 μm in diameter. As cellular division of Streptococcus spp.
What antibiotics treat Streptococcus pyogenes?
The recommendation for S pyogenes pharyngitis in adults is a single intramuscular (IM) dose of benzathine penicillin G 1.2 million units or penicillin V 500 mg PO BID for 10 days. For S pyogenes necrotizing fasciitis in adults, IV penicillin G (up to 24 million units daily in divided doses q4-6h) is recommended.
Is Lipoteichoic acid an exotoxin?
We have recently confirmed that lipoteichoic acid (LTA), a major constituent of the gram-positive bacterial surface, is the endotoxin of gram-positive bacteria that induces proinflammatory molecules in a Toll-like receptor 2 (TLR2)-dependent manner.
Where is Lipoteichoic acid found?
cell wall
Lipoteichoic acid (LTA) is a major constituent of the cell wall of gram-positive bacteria. These organisms have an inner (or cytoplasmic) membrane and, external to it, a thick (up to 80 nanometer) peptidoglycan layer.
What happens if Streptococcus pyogenes is not treated?
If untreated, strep throat can cause complications, such as kidney inflammation or rheumatic fever. Rheumatic fever can lead to painful and inflamed joints, a specific type of rash, or heart valve damage.
What is the best treatment for Streptococcus pyogenes?
Treatment / Management The drug of choice for treatment of bacterial pharyngitis is oral penicillin for 10 days or IM benzathine penicillin. This treatment is cost-effective and has a narrow spectrum of activity. Severe invasive S. pyogenes infections can be treated with vancomycin or clindamycin.
What does streptococcus bacteria look like?
Under a microscope, streptococcus bacteria look like a twisted bunch of round berries. Illnesses caused by streptococcus include strep throat, strep pneumonia, scarlet fever, rheumatic fever (and rheumatic heart valve damage), glomerulonephritis, the skin disorder erysipelas, and PANDAS. Familiarly known as strep.
What are the antigenic components of Streptococcus pyogenes?
Antigenic components include capsular polysaccharide (C-substance), cell wall peptidoglycan and lipoteichoic acid (LTA), and a variety of surface proteins, including M protein , fimbrial proteins, fibronectin-binding proteins, (e.g. Protein F ) and cell-bound streptokinase .
What is the role of lipoteichoic acid in bacteria?
Lipoteichoic acid (LTA) is a complex component of cell walls of Gram-positive bacteria that are involved in a wide range of cell processes such as the stimulation of immune responses and cell signaling pathways. LTA differs between species of gram-positive bacteria.
How does Streptococcus pyogenes spread to other tissues?
Streptococcal invasins lyse eukaryotic cells, including red blood cells and phagocytes; they lyse other host macromolecules, including enzymes and informational molecules; they allow the bacteria to spread among tissues by dissolving host fibrin and intercellular ground substances.
How are pyrogenic exotoxins used in streptococcal disease?
Pyrogenic Exotoxins. Three streptococcal pyrogenic exotoxins (SPE), formerly known as Erythrogenic toxin, are recognized: types A, B, C. These toxins act as superantigens by a mechanism similar to those described for staphylococci. As antigens, they do not requiring processing by antigen presenting cells.
