Case Study Reports: Group B Streptococcus

GROUP B STREPTOCOCCUS

History

You are asked to see a woman in the antenatal assessment unit. She is gravida 4, para 1, having had a normal vaginal delivery 3 years ago, a first-trimester miscarriage and two first-trimester terminations.

She is currently 26 weeks’ gestation. One week ago she was seen because she experienced vaginal bleeding. At the time a small cervical ectropion had been noticed and as the bleed had occurred postcoitally, it was assumed likely to be secondary to the ectropion.

However, as per protocol, she had vaginal and endocervical swabs sent and a full blood count and group and save sample requested.

Questions

·              How would you interpret these results?

·              How would you manage the pregnancy and delivery in light of these results?

Answer:

The key results are

·              mild anaemia

·              group B streptococcus carrier

·              candida.

The anaemia is mild for pregnancy and as the mean cell volume is low, suggesting iron deficiency, it may be treated with ferrous sulphate 200 mg twice daily, with repeat haemo- globin after 4 weeks. She should also be advised about an appropriate iron-rich diet (e.g. meat, lentils, spinach).

Candida organisms are present very commonly in the vagina, particularly in pregnancy. This should be treated (with vaginal clotrimoxazole) only if the woman is symptomatic (itching or lumpy discharge).

Group B streptococcus (GBS)

GBS (Streptococcus agalactiae) colonization occurs in 25 per cent of women at some stage during their pregnancy. In this case the finding of GBS may relate to the presenting symp- tom of bleeding, but is most likely to be an incidental finding. This is the most important result as there is a risk of GBS to the baby with an incidence of 1 in 2000 neonates being infected, with 6 per cent mortality.

In the UK, universal screening for GBS has not been shown to be effective in reducing neonatal death.

Management

Antenatal treatment does not seem to reduce the neonatal risk (perhaps because of recoloniza- tion). However measures are taken to reduce transmission to the baby at the time of delivery:

·              intravenous penicillin (or clindamycin or erythromycin if allergic) should always be given to the mother in labour

·              neonatal care depends on the clinical scenario but may include:

·              observation of the baby for up to 5 days postpartum for signs of sepsis

·              consideration of culture of the baby for evidence of infection (ear, nose, axilla)

·              intravenous antibiotics until culture results confirm no evidence of infection.