Testing for Group B Streptococcus

Group B Streptoccus (GBS)* using Enriched Culture Medium (ECM)

Group B Streptococcus (GBS) is the commonest cause of life-threatening infections in newborn babies in the UK. Most GBS infections can be prevented with intravenous antibiotics, given at the onset of labour. This reduces the likelihood of early-onset GBS infection developing in a baby born to a woman carrying GBS at the time of delivery from around 1 in 300 to less than 1 in 6000.



Babies are usually exposed to GBS shortly before or during birth. It is not understood why some babies are susceptible to the bacteria and develop infection, whilst others do not. What is clear, however, is that most GBS infections in newborn babies can be prevented by giving higher risk women intravenous antibiotics from the onset of labour until the baby is born. Complications that arise during a neonatal GBS infection are serious and can involve septicemia, pneumonia, meningitis, as well as visual and auditory problems and death in one out of every 20 babies who are infected.



GBS is a common commensal bacterium - approximately 30% of the population are colonised with the bacterium in their intestines - it does not cause harm and does not require treatment. Approximately 25% of women of childbearing age carry GBS in the vaginal-rectal area at any one time.



Testing for GBS at The Doctors Laboratory has, to date, used an Enriched Culture Medium (ECM) specifically designed for the isolation of GBS in swabs. This method is not routinely provided by the NHS. Two swabs (lower vaginal and rectal) need to be cultured at 35-37 weeks' gestation to best predict colonisation with GBS around the time of delivery.

 TDL provides a high level service for testing of GBS using the ECM method for the detection of Group B Streptococcus (GBS) in pregnant women at the time of delivery or at any other stage of their pregnancy.

*Group B Strep Support (preventing GBS infection in newborn babies), www.gbss.org.uk

TDL follow's the HPA's BSOP58 for all tests for GBS carriage.