Group B Streptococcus Infections in Maternal and Neonatal Health

Group B Streptococcus (GBS; Streptococcus agalactiae) is a leading cause of maternal and neonatal infections worldwide. It commonly colonises the rectovaginal tract of pregnant women, with asymptomatic carriage rates of 15–30%, and can ascend to the intrauterine environment or be transmitted during labour, resulting in early-onset sepsis, pneumonia or meningitis in neonates. In high-income settings, intrapartum antibiotic prophylaxis has substantially reduced early-onset disease, but late-onset infections—often originating from intestinal colonisation—remain unaffected by this strategy. Maternal comorbidities such as gestational diabetes and alterations in the vaginal microbiota influence the risk of in utero dissemination, while serotype distribution varies geographically, complicating vaccine design. Emerging evidence highlights placental invasion, pro-inflammatory cytokine responses and the role of maternal immunity in determining neonatal outcomes. Antimicrobial resistance and diagnostic delays further exacerbate the global burden. Advances in molecular epidemiology, immunological profiling and maternal immunisation research are converging towards tailored prevention strategies, rapid intrapartum testing and microbiome modulation. A detailed understanding of host–pathogen interactions, regional epidemiology and serotype dynamics is essential to reduce neonatal morbidity, mortality and long-term sequelae.

Research from Nature Portfolio

Recent studies have deepened insights into placental infection and maternal risk factors. Analysis of placental tissue from term births detected GBS DNA in approximately 1 in 200 cases, revealing a threefold increase in neonatal unit admissions and elevated pro-inflammatory cytokines in cord blood. A murine model of gestational diabetes demonstrated that hyperglycaemic conditions impair uterine natural killer cell activation, alter the vaginal microbiota and promote in utero GBS dissemination, leading to worsened neonatal outcomes. Foundational genomic analyses have traced the emergence of dominant GBS clones to mid-20th-century tetracycline use, showing how antibiotic-driven selection shaped the current population structure and enhanced virulence potential.

Group B Streptococcus Infections in Maternal and Neonatal Health publication trend

The graph below shows the total number of articles in group b streptococcus infections in maternal and neonatal health across all publications each year (not limited to Nature Index journals).

Technical terms

Colonisation: Asymptomatic carriage of bacteria on mucosal surfaces without invasive disease.

Intrapartum antibiotic prophylaxis (IAP): Administration of antibiotics during labour to prevent vertical transmission of pathogens.

Serotype: Classification of bacteria based on distinct surface antigens, critical for vaccine design.

Cytokine: Small proteins released by immune cells that mediate inflammation and cell signalling.

Dysbiosis: Disruption of the normal microbial community structure, often linked to disease susceptibility.

References

1. Placental Streptococcus agalactiae DNA is associated with neonatal unit admission and foetal pro-inflammatory cytokines in term infants. Nature Microbiology (2023).
2. Gestational diabetes augments group B Streptococcus infection by disrupting maternal immunity and the vaginal microbiota. Nature Communications (2024).
3. Prevalence of group B Streptococcus colonisation in mother–newborn dyads in low-income and middle-income south Asian and African countries: a prospective, observational study. The Lancet Microbe (2024).
4. Neonatal intestinal colonization of Streptococcus agalactiae and the multiple modes of protection limiting translocation. Gut Microbes (2024).
5. Streptococcus agalactiae clones infecting humans were selected and fixed through the extensive use of tetracycline. Nature Communications (2014).
6. Status of vaccine research and development of vaccines for GBS. Vaccine (2016).
7. Intrapartum GBS screening and antibiotic prophylaxis: a European consensus conference. The Journal of Maternal-Fetal & Neonatal Medicine (2014).
8. Group B Streptococcal Colonization, Molecular Characteristics, and Epidemiology. Frontiers in Microbiology (2018).
9. Infant Group B Streptococcal Disease Incidence and Serotypes Worldwide: Systematic Review and Meta-analyses. Clinical Infectious Diseases (2017).