Intrapartum Antimicrobial Prophylaxis of Group B Streptococcus (GBS)

  • At 36 0/7 to 37 6/7 weeks of gestation, obtain single swab from lower vagina and anorectum (Indicate on requisition if patient ß-lactam allergic as lab will perform susceptibility testing for clindamycin and vancomycin)
  • Give intrapartum prophylactic antibiotics upon commencement of labour if:
    • culture positive for GBS or
    • GBS bacteriuria during present pregnancy or
    • previous baby with invasive GBS disease or
    • unknown GBS status and patient has one or more of the following risk factors:
      • pre-term labour (< 37 weeks gestation)
      • prolonged rupture of membranes ( ≥ 18h) and/or labour expected to last ≥ 18h at term (≥ 37 weeks)
      • maternal fever (≥ 38ºC)
References
 
Antimicrobial Regimen Dose & Duration
- Ampicillin + gentamicin recommended if chorioamnionitis suspected.
Penicillin 5MU IV given ideally at least 4h prior to delivery then
  2.5-3MU IV q4h until delivery or labour stops

Alternative 

Ampicillin 2g IV given ideally at least 4h prior to delivery then
  1g IV q4h until delivery or labour stops

Low risk ß-lactam allergy

Antimicrobial Regimen Dose & Duration
Cefazolin 2g IV given ideally at least 4h prior to delivery then
  1g IV q8h until delivery or labour stops

High risk ß-lactam allergy/anaphylaxis

Antimicrobial Regimen Dose & Duration
Clindamycin 900mg IV q8h until delivery or labour stops

Alternative if clindamycin resistance or unknown susceptibility to clindamycin

Vancomycin 20mg/kg (max 2g) IV q8h until delivery or labour stops