Group B Streptococcus

What causes Group B Streptococcus?

Group B Streptococcus, or GBS, is the most common cause of life-threatening infection in newborn babies in the UK. The bacteria is carried by approximately one third of adults in their intestines and for most people it doesn't usually cause problems. Roughly a quarter of women of childbearing age carry GBS in the vagina at any one time. If a pregnant woman is infected with GBS, there is a chance that the bacteria can be passed from mother to baby around the time of labour.

What are the affects of Group B Streptococcus?

Most babies will not be harmed if their mother is infected, but for some babies it can be deadly, causing meningitis and blood poisoning. GBS affects one in 1,000 babies in the UK (the equivalent of 700 babies per year) and sadly one in eight babies infected with GBS will die. GBS can cause early birth, stillbirth, late miscarriage and complications. Of those that survive GBS meningitis, up to a third are left with long-term mental and physical problems. These can be very severe and can include sight loss, loss of hearing and lung damage.

More rarely it can cause infection in adults, typically women during pregnancy or after birth, the elderly and people with impaired immune systems.

How can it be prevented?

A simple swab test is available for GBS but this isn't done routinely in pregnancy because results are not always reliable (it only picks up around 50% of carriers). Another test which is more reliable, called the enrichment culture method (ECM) test, has recently become available but is not yet routinely given through the NHS. If you wish to pay for it, this test can be arranged through your GP.

Carrying GBS does not mean necessarily that you or your baby will become ill. A positive swab result for GBS means you were colonised at the time the swab was taken - not that you or your baby will become ill.

Pregnant women who test positive for GBS should be given intravenous antibiotics during labour to stop them passing the infection to their baby, ideally for at least four hours before their baby is born.

There are also recognised situations when a pregnant woman requires treatment because there is an increased chance that her baby will be exposed to GBS. These include if:

you have given birth to a baby infected with GBS in the past.
you have been shown to carry GBS in your urine during your current pregnancy (this should be treated when diagnosed, but even if you have been treated, extra precautions should still be taken during labour - see above).
labour starts early (before 37 weeks gestation).
your waters break early (before 37 weeks gestation) with or without other signs of labour.
your waters break more than 18-24 hours before giving birth.
you have a raised temperature* during delivery (of 37.8°C or higher although if a woman has had an epidural, this may be of less significance).

Experts advise that the risk of a GBS infection in the baby must be balanced against the wishes and beliefs of the woman in labour and against her risk of an adverse reaction to the antibiotics. Some women prefer not to receive antibiotics if their risk is only slightly increased.

Scientists are trying to develop a vaccine for GBS, but technical problems mean that it's likely to be some years before one is available.

For this reason it's important that pregnant women and their family members know when babies are most likely to develop a GBS infection and what the symptoms of GBS in babies are.

What are the symptoms of GBS in babies?

Early-onset GBS (0 to 6 days)

Up to 90% of GBS infections in babies occur in the first 6 days of life (60% are apparent at birth). This is known as 'early-onset' GBS, which usually causes septicaemia with pneumonia.

Typical symptoms of early-onset GBS infection include:

grunting.
poor feeding.
lethargy.
low blood pressure.
irritability.
abnormal temperature (high or low), heart rate and/or breathing rate (fast or slow) which can cause blueness of the skin due to lack of oxygen.

Late onset GBS (6 days to 3 months)

Around 10% of GBS infections develop after the baby is 6 days old. This is referred to as 'late-onset' GBS, which usually causes meningitis with septicaemia.

Typical symptoms of late-onset GBS infection, including meningitis, may include any of the following (some may not be present at all):

fever.
poor feeding and/or vomiting.
drowsiness.

As well as any of the signs listed above, symptoms of meningitis in babies, including GBS meningitis may include any of the following (some may not be present at all):

blotchy skin, quite pale or turning blue • dislike of being handled, fretful.
tense or bulging soft spot (fontanelle) on the baby's head.
poor feeding.
high pitched cry/irritable (especially when being held).
floppy body.
stiff body/jerking movements.
blank, staring or trance-like expression.
abnormal breathing rate (low or high).
dislike of bright lights.

Early diagnosis and treatment is vital in 'late-onset' GBS infection or meningitis so, if your baby shows any of the signs above, go IMMEDIATELY to your nearest GP or Casualty unit.