Rapid diagnosis of intrapartum group B streptococcal carriage by fluorescent in situ hybridisation

Group B streptococcus (GBS) still causes considerable neonatal morbidity and mortality. Early-onset infections (appearing within seven days of birth) account for about 80% of infections and are thought to arise from contact with the organism in the maternal genital tract during delivery.¹

Data from the United States in the 1970s estimated an incidence rate of greater than 2 per 1000 live births, and case fatality rates approaching 50%.² However, the use of intrapartum prophylaxis with antibiotics led to a 70% decline in GBS disease during the 1990s.³ In the UK, a recent study found an incidence of early-onset sepsis exceeding 0.72 per 1000 live births, with a mortality of 9.7%, rising to 15% in premature infants.⁴

Controversy remains about the optimal strategy for prevention. In the United States, the delivery of intrapartum antibiotics to at-risk mothers has shifted from a risk-based approach to one based on a universal culture-based screen for vaginal and rectal GBS carriage at 35–37 weeks’ gestation.⁵ All women found to be carriers at 35–37 weeks (or labouring before this time) are offered prophylaxis. In the UK, routine screening is not recommended as there are doubts about delivery and cost effectiveness; instead, a risk factor-based approach is advocated.⁶ Intrapartum …