A streptococci

from Wikipedia, the free encyclopedia

The division of living beings into systematics is a continuous subject of research. Different systematic classifications exist side by side and one after the other. The taxon treated here has become obsolete due to new research or is not part of the group systematics presented in the German-language Wikipedia.

A streptococci are a subgroup of beta-hemolytic streptococci . You belong to Lancefield Group A. They mainly colonize the human skin and the throat. Streptococcus pyogenes has the greatest medical importance among the A streptococci.

features

Streptococcus pyogenes

Due to their different serotypes , the A streptococci are among the most flexible gram-positive pathogens . They are classified according to the Lancefield scheme based on the antigenic differences of the C-polysaccharide ; they contain antigens of group A. The variants of the M-protein ( serovars ) anchored in the murein layer allow over 80 serologically different serotypes to be differentiated. So one speaks z. B. of β-hemolytic streptococci of group A, type 27.

Systematics and taxonomy

The counting of the group A streptococci species are representatives of the genus Streptococcus in the family of Streptococcaceae in the order of Lactobacillales (lactic acid bacteria) that the Department of Firmicutes belong.

At the beginning of the 20th century, the streptococci were divided into Streptococcus viridans and Streptococcus hemolyticus , the former performing α-hemolysis and the latter performing β-hemolysis and were recognized as pathogens early on. The classification according to the antigens that was introduced by Rebecca Lancefield in 1933 contributed significantly to the differentiation between the pathogenic species and strains . Subsequent attempts to classify these streptococci into species are based on the Lancefield groups. The A-streptococci were equated by some scientists with Streptococcus pyogenes , while others saw it as a group that also includes representatives who do not belong to this species. It was only later demonstrated that anginosus streptococci (previously referred to as Streptococcus milleri , they form a subgroup of the Viridans streptococci ) can have antigens of Lancefield group A, but this is the case in less than 10% of anginosus streptococci.

Occurrence

A streptococci primarily colonize human skin and the throat , around a third of the population carries the pathogen - mostly asymptomatic .

Medical importance

Occasionally, however, there are serious A-streptococcal infections, which then often have a fulminant course, such as necrotizing fasciitis or the streptococcal toxic shock syndrome . In rare cases, A streptococci are found to cause pyomyositis . Streptococcal infections are usually treated orally with penicillins (e.g. penicillin V).

Legal Aspects

If an infection with A streptococci occurs in a hospital , the hospital management has a number of special duties of care , the violation of which can lead to liability towards the patient concerned. The Oldenburg Higher Regional Court pointed this out in a judgment.

swell

literature

  • Helmut Hahn, Stefan HE Kaufmann, Thomas F. Schulz, Sebastian Suerbaum (eds.): Medical microbiology and infectiology . 6th edition. Springer Verlag, Heidelberg 2009, ISBN 978-3-540-46359-7 , p. 203-221 .

Individual evidence

  1. ^ Jean Euzéby, Aidan C. Parte: Genus Streptococcus. In: List of Prokaryotic names with Standing in Nomenclature ( LPSN ). Retrieved July 22, 2014 .
  2. ↑ a b James M. Sherman: The Streptococci. In: Bacteriological reviews. Volume 1, No. 1, December 1937, pp. 3-97, ISSN  0005-3678 . PMID 16350049 . PMC 440821 (free full text).
  3. ^ Rebecca C. Lancefield: A Serological Differentiation Of Human And Other Groups Of Hemolytic Streptococci. In: The Journal of experimental medicine. Volume 57, No. 4, March 1933, pp. 571-595, ISSN  0022-1007 . PMID 19870148 . PMC 2132252 (free full text).
  4. ↑ Jan Adriaan Jacobs: Streptococcus milleri: Relevance of species . In: Dissertation at the Rijksuniversiteit Limburg te Maastricht . 1996, p. 1–113 ( unimaas.nl [PDF; 9.1 MB ; accessed on July 23, 2014]).
  5. ↑ Archived copy ( Memento of the original from December 19, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. . @1@ 2Template: Webachiv / IABot / www.cdc.gov
  6. ↑ OLG Oldenburg, judgment of December 3, 2002 ( Memento of January 11, 2016 in the Internet Archive ), Az. 5 U 100/00, full text.