Maternal group B Streptococcus and the infant gut microbiota

Area of Science:

• Microbiology
• Pediatrics
• Public Health

Background:

• Early life gut microbiome development is crucial for long-term health.
• Maternal carriage of group B strep (GBS; *Streptococcus agalactiae*) is common during pregnancy.
• The impact of maternal GBS status on the infant gut microbiome remains largely unknown.

Purpose of the Study:

• To investigate whether maternal GBS status influences the composition of the infant gut microbiome.
• To identify specific bacterial taxa affected by maternal GBS carriage in infants.

Main Methods:

• Collected infant stool specimens at ~1 and 6 months of age from a birth cohort.
• Sequenced the V4 region of the bacterial 16S rRNA gene using Illumina MiSeq.
• Analyzed gut bacterial community composition differences by maternal GBS status using statistical models, adjusting for confounders.

Main Results:

• Maternal GBS status was significantly associated with infant gut bacterial composition at 6 months (Canberra R²=0.008, P=0.008; Unweighted UniFrac R²=0.010, P=0.011), after adjusting for covariates.
• Infants born to GBS-positive mothers showed enrichment of specific bacteria from Clostridiaceae, Ruminococcoceae, and Enterococcaceae families at 6 months.
• No significant association was observed at the 1-month visit.

Conclusions:

• Maternal GBS carriage is associated with specific alterations in the infant gut microbiome by 6 months of age.
• These findings highlight the potential role of maternal GBS status in shaping early life microbial exposures.
• Further research is needed to determine if these microbial differences predispose infants to adult diseases.