Streptococcus agalactiae

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Streptococcus agalactiae
Systematics
Department : Firmicutes
Class : Bacilli
Order : Lactic acid bacteria (Lactobacillales)
Family : Streptococcaceae
Genre : Streptococcus
Type : Streptococcus agalactiae
Scientific name
Streptococcus agalactiae
( Nocard & Mollereau 1887)
Lehmann & Neumann , 1896
S. agalactiae in the positive CAMP test (arrow-shaped increased β-hemolysis ) with S. aureus .

Streptococcus agalactiae is a gram-positive bacterium that can cause various infectious diseases. The species was first described in 1887 by Nocard and Mollereau as Streptococcus de la mammite . It belongs serologically for Lancefield group B of streptococci (GBS) and is the main cause of bacterial sepsis , pneumonia and meningitis in newborns and puerperal fever . Infections in immunosuppressed peopleare also becoming increasingly common. Although Streptococcus agalactiae is part of the normal flora of the gastrointestinal and genital tract, it can cause a life-threatening infection with the appropriate disposition.

Because of its importance as a cause of severe neonatal infections (e.g. neonatal sepsis ), a preventive examination for Streptococcus agalactiae is recommended in pregnant women at the end of pregnancy (35th – 37th week of pregnancy). This examination is now also referred to as B streptococcal screening in Germany . As part of this examination, the gynecologist will take a bacteriological smear from the vaginal entrance area and from the rectum; this smear is examined for S. agalactiae by a microbiological laboratory . The examination in the laboratory lasts 2-3 days. If S. agalactiae is detected in the pregnant woman , the maternity hospital will carry out (intrapartum) prophylactic treatment with penicillin or another antibiotic at birth. Large studies in the United States have shown that this approach can prevent most newborn infections from B strep.

An important characteristic of this bacterium is complete hemolysis (also known as beta hemolysis ) on blood agar plates. This is also used for diagnostic purposes. The identification is then carried out by agglutination with an antiserum directed against the cell wall polysaccharide of S. agalactiae . Alternatively, the so-called Granada agar can be used, an indicator nutrient medium on which B streptococci can be recognized by a color change.

Penicillin G , combined with gentamicin , or ampicillin , possibly combined with gentamicin, and alternatively cefotaxime can be used for intravenous therapy of severe infections caused by group B streptococci . Oral intake of amoxicillin or cefuroxime axetil may be sufficient for milder infections .

literature

  • CDC Guidelines: Prevention of Perinatal Group B Streptococcal Disease (2002).
  • Recommendations of the Dt. Society for Gynecology and Obstetrics 2004.
  • AWMF guidelines: prophylaxis of neonatal sepsis from strepticocci of group B. 2008.
  • Marianne Abele-Horn: Antimicrobial Therapy. Decision support for the treatment and prophylaxis of infectious diseases. With the collaboration of Werner Heinz, Hartwig Klinker, Johann Schurz and August Stich, 2nd, revised and expanded edition. Peter Wiehl, Marburg 2009, ISBN 978-3-927219-14-4 , p. 231 f.

Individual evidence

  1. ↑ UniProt Taxonomy: Streptococcus agalactiae
  2. ↑ Gil E. García, MC Rodríguez, R. Bartolomé, B. Berjano, L. Cabero, A. Andreu: Evaluation of the Granada Agar Plate for Detection of Vaginal and Rectal Group B Streptococci in Pregnant Women . In: Journal of Clinical Microbiology . tape 37 , no. 8 , August 1999, ISSN  0095-1137 , pp. 2648-2651 , PMC 85303 (free full text).
  3. ^ G. Claeys, G. Verschraegen, M. Temmerman: Modified Granada Agar Medium for the detection of group B Streptococcus carriage in pregnant women . In: Clinical Microbiology and Infection . tape 7 , no. 1 , January 2001, p. 22-24 , doi : 10.1046 / j.1469-0691.2001.00156.x , PMID 11284939 (free full text).
  4. ^ Marianne Abele-Horn: Antimicrobial Therapy. Decision support for the treatment and prophylaxis of infectious diseases. With the collaboration of Werner Heinz, Hartwig Klinker, Johann Schurz and August Stich, 2nd, revised and expanded edition. Peter Wiehl, Marburg 2009, ISBN 978-3-927219-14-4 , p. 231.