Infections cause by A group Streptococci

Streptococcal infections are among the most common bacterial infections. Streptococci are obligately pathogenic, facultatively pathogenic and saprophytic microorganisms. We classify them according to the degree of hemolysis - α-hemolytic (incomplete, partial hemolysis on agar) and β-hemolytic (complete, complete hemolysis), according to serological differentiation of capsule antigen C into groups A and B.

The most common infections caused by group A streptococci include:

A group Streptococci[edit | edit source]

Group A streptococci are the cause of 90% of streptococcal infections,
toxins: erythrogenic toxin, streptolysin O and streptolysin S (hemolysis, toxic to myocardial fibers and hepatocytes), streptokinase (fibrinolysis), hyaluronidase (invasive factor of streptococci), etc.
against some streptococci, Ig is formed useful in diagnosis - ASLO (antistreptolysin O) - they decline in the few weeks after infection.
cause a variety of diseases: - damage to the skin and mucous membranes, prolonged seropurulent rhinitis in young children, scarlet fever, impetigo, tonsillitis and pharyngitis

Complications of sore throat and scarlet fever[edit | edit source]

Submandibular node covation, retrotonsillar or paratonsillar abscess, otitis, mastoitis, sinusitis,
more rarely - bacteremia, metastatic foci - purulent arthritis, endocarditis, meningitis, brain abscess, osteomyelitis and mediastinitis. Transmission of infection to the mediastinum is a rare but very dangerous complication with a high mortality rate.
without therapy - risk of late complications - rheumatic fever or glomerulonephritis.

Rheumatic fever[edit | edit source]

Most often after group A streptococci, 1-4 weeks after infection (about 3% infected),
the course of the original infection may be inapparent (without obvious symptoms),
acute immunological multisystemic inflammation,
often affects the heart - chronic changes in the valves,
main manifestations: migrating polyarthritis, pancarditis, subcutaneous nodules, erythema marginatum and Sydenham's chorea - dance of St. Vita, chorea minor (neurological disorder - unconscious untargeted rapid movements),
side effects: non-specific - fever, joint pain, increased CRP…,
diagnosis: Jones criteria - history of streptococcal infection, presence of at least two manifest symptoms (major or minor)
pathogenesis: hypersensitivity reactions, Ig against M protein of streptococci cross-react with glycoproteins of heart muscle, joints, etc.,
relapses.