Neonatal group B streptococcal disease

Group B Streptococcus (GBS) is a leading cause of neonatal sepsis in developed countries, with early-onset disease occurring in neonates during days 0–6 of life ^[2].

GBS colonization during pregnancy is associated with significant neonatal morbidity and mortality, and neonatal GBS is a leading cause of neonatal sepsis in developed countries ^[3][2]. Clinical scenarios triggering intrapartum intervention across major obstetric guidelines include GBS bacteriuria during pregnancy, clinical signs of chorioamnionitis, maternal pyrexia, and a history of GBS-related neonatal disease ^[3].

Among GBS-colonized pregnant women in settings without an IAP policy, the risk of early-onset neonatal GBS disease is approximately 1.1% (95% CI 0.6%–1.5%), consistent with earlier single-study estimates of 1%–2% ^[1]. Reported neonatal GBS incidence in developing countries ranges from 0 to 3.06 per 1000 live births, with substantial variation within and between geographic regions and most case identification occurring within hospital settings ^[2]. Incidence estimates are influenced by case-finding methods, with automated culture techniques yielding higher reported rates ^[2].

Early-onset neonatal GBS disease results from vertical transmission of group B Streptococcus from mothers who are rectovaginally colonized during pregnancy ^[1]. Risk of early-onset disease in the neonate is directly related to maternal colonization status, and this risk falls linearly with increasing intrapartum antibiotic prophylaxis coverage ^[1].

Intrapartum antibiotic prophylaxis, principally penicillin, given to carrier mothers has unequivocally decreased early-onset neonatal GBS sepsis ^[4]. Screening-based strategies using combined vaginal and rectal swabs collected between 35 and 37 weeks gestation, inoculated onto selective media after enrichment, are considered more effective than risk-based approaches for identifying candidates for prophylaxis ^[4]. Major guidelines converge on intrapartum antibiotic indications including bacteriuria during pregnancy, chorioamnionitis, maternal pyrexia, and prior GBS-affected neonate, and they agree that antepartum treatment of GBS and prophylaxis for GBS-positive women with planned cesarean delivery and intact membranes are not recommended ^[3]. Increasing antimicrobial resistance to erythromycin and clindamycin abroad may affect agent choice in penicillin-allergic women, and novel maternal GBS vaccines are under development to provide broader protection ^[4].

1. 1Russell NJ et al. Risk of Early-Onset Neonatal Group B Streptococcal Disease With Maternal Colonization Worldwide: Systematic Review and Meta-analyses. Clin Infect Dis. 2017 Nov 6. PMID: 29117325. doi: 10.1093/cid/cix655.PubMed: https://pubmed.ncbi.nlm.nih.gov/29117325/
2. 2Dagnew AF et al. Variation in reported neonatal group B streptococcal disease incidence in developing countries. Clin Infect Dis. 2012 Jul. PMID: 22523262. doi: 10.1093/cid/cis395.PubMed: https://pubmed.ncbi.nlm.nih.gov/22523262/
3. 3Boureka E et al. Prevention of Early-Onset Neonatal Group B Streptococcal Disease: A Comprehensive Review of Major Guidelines. Obstet Gynecol Surv. 2023 Dec. PMID: 38134342. doi: 10.1097/OGX.0000000000001223.PubMed: https://pubmed.ncbi.nlm.nih.gov/38134342/
4. 4Daley AJ et al. Prevention of neonatal group B streptococcal disease: progress, challenges and dilemmas. J Paediatr Child Health. 2004 Dec. PMID: 15569279. doi: 10.1111/j.1440-1754.2004.00507.x.PubMed: https://pubmed.ncbi.nlm.nih.gov/15569279/
5. 5Money D et al. The Prevention of Early-Onset Neonatal Group B Streptococcal Disease. J Obstet Gynaecol Can. 2016 Dec. PMID: 28063544. doi: 10.1016/j.jogc.2016.09.042.PubMed: https://pubmed.ncbi.nlm.nih.gov/28063544/