🔑 Key Learning

  • GBS is a common commensal bacterium but a major cause of neonatal sepsis, pneumonia, and meningitis.
  • UK does not offer routine GBS screening; risk-based strategy is followed instead.
  • IV antibiotics (benzylpenicillin) are indicated in labour if GBS is detected during pregnancy or if risk factors are present.

🧬 Pathophysiology

  • GBS (Streptococcus agalactiae) colonises the maternal rectovaginal tract.
  • Transmission to the neonate occurs during labour or delivery.
  • Neonatal infection can present as early-onset (within 7 days) or late-onset (after 7 days).

🧪 Detection

  • Routine antenatal screening is not recommended in the UK.
  • GBS is often identified incidentally:
    • Urine culture during antenatal screening
    • High vaginal/rectal swab during investigations for other symptoms
  • Positive GBS culture during the current pregnancy warrants intrapartum prophylaxis.

⚠️ Risk Factors for Neonatal GBS Disease

  • Previous baby affected by GBS
  • GBS bacteriuria or positive swab in current pregnancy
  • Maternal fever during labour (≥38°C)
  • Preterm labour (<37 weeks)
  • Prolonged rupture of membranes (>24 hours)

💊 Management

🧪 Positive GBS culture or previous GBS-affected baby:

  • IV antibiotics during labour:
    • 1st line: Benzylpenicillin
    • Begin as soon as labour starts or membranes rupture
    • Continue every 4 hours until delivery

🧪 GBS bacteriuria >10⁵ CFU/mL:

  • Treat at time of diagnosis:
    • Oral amoxicillin for asymptomatic bacteriuria
  • PLUS: IV antibiotics in labour (as above)

📝 Exam Clues & Clinchers

  • GBS in urine → treat now and give IV antibiotics during labour
  • Previous baby with GBS infection → IV antibiotics in all future labours
  • GBS not screened for routinely — detected incidentally
  • Labour with prolonged rupture or maternal fever → give IV antibiotics

🔗 Useful Links and References