Group A streptococcal infection
Streptococcal infections are among the most common bacterial infections. Streptococci are obligately pathogenic, facultative pathogenic and saprophytic micoorganisms. We classify them according to the degree of hemolysis – α-hemolytic (incomplete, partial hemolysis on agar) and β-hemolytic (complete, complete hemolysis), according to the serological differentiation of capsular antigen C into A and B.
Group A streptococci are the cause of 90% of streptococcal infections. Bacteria produce a number of toxins: erythrogenic toxin, streptolysin O a streptolysin S (causes hemolysis and is toxic to myocardial fibers and hepatocytes), streptokinase (fibrinolysis), hyaluronidase (invasive factor of streptococci), etc. Against some toxins, Ig is formed that can be used in diagnostics – ASLO (antistreptolysin O) – they decrease in a few weeks after infection. Group A streptococci cause various diseases: – skin and mucous membrane involvement , protracted seropurulent rhinitis, scarlet fever, impetigo, tonsillopharyngitis in young children.
The most common infections caused by group A streptococci include:
Complications of angina and scarlet fever[edit | edit source]
- Multiple submandibular nodes, retrotonsillar, paratonsillar abscess, otitis, mastoitis, sinusitis,
- more rarely – bacteremia, metastatic foci – purulent arthritis, endocarditis, meningitis, brain abscess, osteomyelitis and mediastinitis. Transfer 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 (in about 3% of those infected),
- the course of the original infection may be inapparent (without obvious symptoms),
- acute immunologically conditioned multisystemic inflammation,
- often affects the heart – chronic changes in the valves,
- main manifestations: migrating polyarthritis, pancarditis, subcutaneous nodules, erythema marginatum and Sydenham's chorea – st. Welcome, chorea minor (neurological disorder – unconscious untargeted rapid movements),
- secondary symptoms: secondary symptoms – fever, joint pain, increased CRP…,
- diagnosis: Jones criteria – history of streptococcal infection, presence of at least two manifest main or secondary symptoms,
- pathogenesis: hypersensitivity reaction, Ig against M protein of streptococci cross-react with glycoproteins of heart muscle, joints etc.,
- relapses.
Complications of streptococcal skin infections[edit | edit source]
- Rarely, septic complications, possibly also glomerulonephritis,
- rheumatic fever rarely,
- acute glomerulonephritis.
Links[edit | edit source]
Related articles[edit | edit source]
- Genus Streptococcus: Streptococcus pyogenes
- Streptococcus agalactiae
- Streptococcus pneumoniae
- Streptococcus mutans
- Streptococcal infections: Group A streptococcal infections
- Feber
- Angina fever
- Erysipelas
- Impetigo
- Infections caused by viridating streptococci
- Complications and treatment of streptococcal infections
- Rheumatic fever
References[edit | edit source]
- BENEŠ, Jiří. Study materials [online]. ©2007. [cit. 2009]. <http://www.jirben.wz.cz/>.
Recommended literature[edit | edit source]
- HRODEK, Otto – VAVŘINEC, Jan, et al. Pediatrics. 1. edition. Galén, 2002. ISBN 80-7262-178-5.
- ŠAŠINKA, Miroslav – ŠAGÁT, Tibor – KOVÁCS, László, et al. Pediatrics. 2. edition. Herba, 2007. ISBN 978-80-89171-49-1.
