GBS Flashcards
Indications for IAP with Universal Screening Approach
- GBS positive at 35-37/40 screen (rectovaginal swabs in selective enrichment broth medium)
- Previous infant with GBS infection
- GBS bacteriuria in current pregnancy
Indications for IAP with Risk Factor Based Approach
- Previous infant with EOGBS
- GBS bacteriuria or colonisation current pregnancy
- Spont PTL
- ROM ≥18 hours
- Fever ≥38 intrapartum or within 24 hours of giving birth
Rate of GBS colonisation of genital tract
10-30%
Rate of early onset GBS disease (within first week of life)
<1 per 1000 live births
Rate of colonisation of infant with GBS positive mother
70%
Universal screening vs risk-based protocols in systematic review
- Reduced risk of EOGBS compared with risk-based approach (RR 0.43 95CI 0.32-0.56)
- Reduced risk of EOGBS compared to no policy (RR 0.31 95CI 0.11-0.84)
When to perform culture screening
After 35 weeks’ gestation
Ideally within 5 weeks of delivery
- The later in pregnancy, the better correlation with culture results at delivery
Cases of EOGBS not associated with maternal risk factors
25-30%
Improvement in detection of GBS with addition of anorectal swab
25%
Onset of symptoms of neonates with EOGBS
90% within 12 hours
Rate of fatal maternal anaphylaxis to penicillin
1 in 100,000
Less severe reactions in 7-10%
Rates of clindamycin and erythromycin resistance in GBS
20% (clinda)
30% (erythro)
IAP choice for penicillin allergy in GBS prophylaxis
No history of anaphylaxis: cefazolin 2g then 1g 8 hourly
Anaphylaxis history: Clindamycin 900mg IV 8 hourly or vancomycin (erythromycin no longer acceptable alternative)
Pathogens responsible for chorioamnionitis
GBS, anaerobic cocci, enteric gram-negative bacilli (often polymicrobial - give broad spectrum antibiotics)
