Group B Streptococcus (GBS) – Innermost Healthcare

What is group B Strep?

Group B Streptococcus (GBS) is a normal bacterium which colonises between 20- 30% of adults in the UK, usually without symptoms or side-effects. It is most commonly found in the intestines, as part of the normal gut flora (bacteria living in the gastrointestinal tract). It is also often found in the vagina of adult women. It is known as a ‘commensal’ – an organism which lives on another without causing any harm.

GBS can, however, occasionally cause infection, most commonly in newborn babies. GBS more rarely causes infection in adults (typically women during pregnancy or after birth, the elderly and people with serious underlying medical conditions which impair their immune system) and more rarely still during pregnancy and before labour.

GBS is not a sexually transmitted disease and treatment of a woman and of her partner carrying GBS does not prevent re-colonisation.

The information for this page and further information on GBS can be found on the Group B Strep Support Website

Group B Strep Infection in Newborn babies

In newborn babies, there are two types of GBS disease: early and late-onset. Roughly 75% of GBS disease is early-onset, occurring in the first 6 days of life and usually apparent at birth. Early-onset GBS disease is normally characterised by the rapid development of breathing problems, associated with blood poisoning. Late- onset disease – which usually presents as GBS meningitis – occurs after the baby is 6 days old and, normally, by age 1 month but, rarely, up to age 3 months. After age 3 months, GBS infection in babies is extremely rare.

GBS is a recognised cause of preterm delivery, maternal infections, stillbirths and late miscarriages.

Preterm babies are known to be at particular risk of GBS infection as their immune systems are not as well developed as those of full-term babies.

Overall, without preventative medicine, GBS infections would affect an estimated 1 in every 1,000 babies born in the UK. Therefore, based on 700,000 babies born annually in the UK, approximately:

Facts and Figures about GBS

230,000 babies would be born to mothers who carry GBS; 88,000 babies (1 in 8) become colonised with GBS; 700 babies would develop GBS infections, usually within 24 hours of birth; and 75 babies (11% of infected babies) would die.

Of the survivors of GBS meningitis, up to one half suffer long-term mental and/or physical problems, from mild to severe learning disabilities, loss of sight, loss of hearing and lung damage (in around 12% of the survivors, the disabilities may be severe). The great majority of survivors of early-onset disease do so with no long-term damage.

In the UK this means on average:

• Every day a baby get GBS
• Every week a baby dies form GBS
• Every 2 weeks a baby survives GBS to be permanently damaged

Testing for GBS

Routine screening of all pregnant women for GBS is not recommended by the UK National Screening Committee nor the Royal College of Obstetricians & Gynaecologists.

Current UK policy uses a ‘risk factor’ approach to determine which newborn babies are likely to be at-risk of developing GBS infection. Risk factors include carrying GBS this pregnancy, high temperature during labour, labour starting or waters breaking prematurely and having previously had a baby infected with GBS.

This risk-based strategy introduced in the UK in 2003 has had little if any effect on the rate of early-onset GBS infections in babies – the rate has not fallen. Furthermore, up to 40% of babies who do become affected are born to mothers without any of these clinical risk factors.

Testing is presently the only way to identify whether a woman is carrying GBS. If GBS is found during the current pregnancy, then steps can be taken to minimise the risk of her newborn baby developing GBS infection.

Click here for latest prices and options for Group B Strep Screening.

When should intrapartum antibiotics be offered?

UK guidelines from NICE and from the Royal College of Obstetricians & Gynaecologists recommend that you should be offered intravenous antibiotics as soon as possible once labour starts and then at regular intervals until the baby is born. This has been shown to be highly effective at preventing GBS infection in newborn babies in the following cases:

• Positive rectal or vaginal swab for GBS in the current pregnancy
• If you have had a previous baby who developed GBS infection
• Urinary tract infection caused by GBS during pregnancy (which should also be treated at the time of diagnosis)
• Positive GBS in a prior pregnancy on its own without an affected baby or other risk factors is NOT an indication for intrapartum antibiotics and you should consider screening again in the current pregnancy.

Women planning a homebirth or a birth in a Midwifery Led Unit need to consider that they may not be able to have intrapartum antibiotics in these settings and may have to deliver in a Consultant Led Obstetric Unit.

No treatment for GBS carriage (GBS detected from vaginal or rectal swabs) is required or shown to be beneficial before labour starts, since no antibiotics tested so far have been shown reliably to eradicate GBS carriage.

View the GBS Support medical panel’s recommended approach to preventing GBS infection in newborn babies click here

Risk Factors for GBS

Pregnant women carrying group B Strep is perfectly normal. GBS can be present at any time – in a woman’s first pregnancy, or in one or more subsequent pregnancies. It can be a threat during pregnancy, around delivery and afterwards. There are certain situations which increase the chance that a newborn baby may, if susceptible, develop GBS infection. Each of the risk factors shown below increases the risk of GBS infection in a newborn baby:

• Mothers who have previously had a baby infected with GBS – risk increased x10
• Mothers who have been shown to carry GBS in this pregnancy or GBS has been found in the urine at any time during this pregnancy – risk increased x4
• Labour starts or membranes rupture before 37 weeks – risk increased x3
• Where the waters break more than 18 hours before delivery – risk increased x3
• Intrapertum raised temperature* of 37.8°C or more – risk increased x3 *If a woman has an epidural, a slightly raised temperature may be of less significance than in a woman with no epidural.
• Carrying GBS, combined with one or more clinical risk factor – risk increased x12

Risk Factors and Outcomes

In the UK, approximately 3 out of every 4 GBS infections in babies aged 0-6 days and 9 out of every 10 resulting deaths follow deliveries where one or more of these risk factors is present.

About half of the babies born to mothers colonised with GBS at the time of delivery will become colonised themselves and, of these, even without preventative antibiotics in labour, only around 1 in 200 will develop GBS disease. Carrying GBS during labour and delivery does not mean necessarily that you or your baby will become ill.

GBS in Non Pregnant Women and in Men

Carrying group B Streptococcus (GBS) is perfectly normal and natural whether you are or you are not pregnant. GBS is a normal bacterium which colonises up to 30% of adults in the UK, usually without symptoms or side-effects. It is most commonly found in the intestines, as part of the normal gut flora (bacteria living in the gastrointestinal tract). It is also often found in the vagina of adult women. It is known as a ‘commensal’ – an organism which lives on another without causing any harm.

A positive vaginal or rectal swab result for GBS means a woman is colonised with or carries GBS at the time the swab was taken – not that she is ill. (If GBS is found in the urine, this is usually GBS infection – urine is normally sterile – and GBS urine infections should be treated at the time of diagnosis with oral antibiotics and the treatment repeated if necessary until urine tests come back clear. Click here for more information.)

GBS can, however, occasionally cause infection, most commonly in newborn babies and more rarely in adults.

GBS infection is diagnosed when the bacteria are grown from body fluids that are usually sterile, such as blood or spinal fluid. These are known as cultures and normally take one to two days to complete.

When GBS infection occurs in adults, it usually (though not always) does so in those with serious underlying medical conditions (such as diabetes mellitus, cancer or liver disease) which reduce the effectiveness of the immune system; the elderly; and pregnant women. And, although uncommon, GBS infection in adults displays a whole spectrum of severity, from easily treated to very serious, particularly in non- pregnant adults.

The overall rate of GBS infection per 100,000 population for 2014 was 2.8 per 100,000 population for England, Wales and Northern Ireland combined (source: PHE). GBS infections in adults are usually skin and soft tissue infections (such as infection of skin ulcers caused by poor circulation and diabetes, or pressure sores in patients confined to bed), blood infection (septicaemia), pneumonia and urinary tract infections (such as kidney, bladder or prostate infections). GBS may also cause meningitis in adults as well as bone infections (osteomyelitis) and deep eye infections (endophthalmitis).

Early recognition and treatment is important for the successful treatment of GBS infection in adults. High doses of antibiotics such as penicillin should be administered and therapy should not be stopped prematurely. In some cases, surgery may be necessary to drain infected sites and remove damaged tissue. GBS infections, especially the more deep-seated ones, require expert care, prolonged courses of antibiotics and sometimes more than one antibiotic at the same time. Due to the varied nature of these infections, it is impossible to generalise about what is the most appropriate treatment.

Most GBS infection can be treated successfully, although some people will require all the expertise of intensive care facilities. Not all hospitals have such a facility and so some ill patients will have to be transferred to one with these specialised facilities.

Further Information on GBS