Group B streptococcal infection

DiseaseDisorder infobox
Name = Streptococcus, group B, as the cause of diseases classified to other chapters
ICD10 = ICD10|B|95|1|b|95
ICD9 =

Infection with Group B Streptococcus (GBS), also known as Streptococcus agalactiae and more colloquially as Strep B and group B Strep, can cause serious illness and sometimes death, especially in newborn infants and the elderly. Group B streptococci are also important pathogens in veterinary medicine, because they can cause bovine mastitis (inflammation of the udder) in dairy cows. The species name "agalactiae" meaning "no milk", alludes to this.

Streptococcus is a genus of spherical, Gram-positive bacteria of the phylum Firmicutes. Streptococcus agalactiae is a gram-positive streptococcus characterized by the presence of Group B Lancefield antigen, and so takes the name Group B Streptococcus.

Perinatal disease

GBS is a member of the normal flora of the gut and female urogenital tract, so many women are carriers of this bacterium without knowing it. GBS colonization can be chronic or intermittent.

GBS bacteria can be passed from a pregnant woman to her baby during labor, if she is a carrier of the bacteria.

Perinatal Group B Streptococcal Disease

25% of women are colonized with GBS in the vagina or rectum.cite web
title = Preventing Group B Strep: Are You Pregnant? Protect your baby from group B strep!
publisher = Center for Disease Control and Prevention
date = 2004-02-09
url = http://www.cdc.gov/groupbstrep/
format = pdf
accessdate = 2007-10-18 ] Since the bacteria can come and go, testing for GBS is recommended by US protocols at 36 weeks of every pregnancy. In the UK, they do not routinely culture at 36 weeks, but rather treat women according to their risk in labor- meaning giving antibiotics to women whose membranes are ruptured more than 18 hours and those who have fever. But in the US, at the 36 week antenatal appointment, the vagina and rectum are swabbed and cultures grown in enriched culture media (ECM), although in some countries suboptimal culture methods are used, which result in up to half of women carrying GBS when swabbed being given a falsely negative test resultFact|date=February 2008. Treatment of GBS positive women with intravenous penicillin at the onset of labour and then 6 hourly reduces early neonatal infection. [cite web | title =Intrapartum antibiotics for Group B streptococcalcolonisation |author=Smaill FM |publisher=Cochrane Library |url=http://mrw.interscience.wiley.com/cochrane/clsysrev/articles/CD000115/pdf_fs.html |accessdate=2008-07-20] , although research has shown that at least 2 hours is also beneficialFact|date=July 2008.

Where insufficient intravenous antibiotics were given before delivery, the baby may given antibiotics immediately after birth, although evidence is inconclusive as to whether this is effective [cite web | url=http://www.cochrane.org/reviews/en/ab003667.html |author=Woodgate P, Flenady V, Steer P | title=Intramuscular penicillin for the prevention of early onset group B streptococcal infection in newborn infants |publisher=Cochrane Library |accessdate=2008-07-20] . Some units take a watchful approach for 24-48 hours, only giving antibiotics if the baby shows any symptoms of infectionFact|date=July 2008. In many centers if a woman presents late in her prenatal period then there may be no time to grow cultures prior to labour. In this situation some clinicians advocate empirical antibiotic cover of mother and baby, although most would only advocate antibiotics for the mother if other recognised risk factors were present.

Perinatal GBS disease prevention

Through collaborative efforts clinicians, researchers, professional organizations, parent advocacy groups, and the public health community developed recommendations for intrapartum prophylaxis to prevent Perinatal GBS disease. Many organizations have developed Perinatal GBS disease prevention and education programs to reduce the incidence of the disease. Information about the recommendations and the prevention programs can be found in medical journals and on the internet.

References

*Brooks, Geo F., Janet Butel, and Stephen Morse. Jawetz, Melnick, and Adelberg's Medical Microbiology, 22nd edition. 2001.
*Gillespie, Stephen and Kathleen Bamford. Medical Microbiology at a Glance. 2000.

External links

* [http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5111a1.htm Prevention of Perinatal Group B Streptococcal Disease] August 16, 2002 MMWR 2000;49:228-232.
* [http://www.strepb.ca/home.htm The Canadian Strep B Foundation]
* [http://www.gbss.org.uk The UK Group B Strep Support charity]