Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2023

Determinants of the milk microbiome in allergic mothers (#162)

Jie Ma 1 , Lisa F Stinson 1 , Ching tat Lai 1 , Debbie J Palmer 2 3 , Donna T Geddes 1
  1. School of Molecular Sciences, University of Western Australia, Crawley, WA, Australia
  2. Telethon Kids Institude, University of Western Australia, Crawley, WA, Australia
  3. School of Medicine, University of Western Australia, Crawley, WA, Australia

 

Background

Allergy is one of the most common chronic diseases over the world. It has been well established the gut microbiome is associated with allergic disease in children and adults. Therefore, we hypothesise that the human milk microbiome differs by maternal allergy status. While numerous studies have examined the factors that shape the milk microbiome of healthy mothers, no such study exists for allergic mothers.

 

Aims

The aim of this study is to assess the maternal, infant, and environment determinants of the human milk microbiome at 3 and 6 months in allergic women.

 

Methods

Full-length 16S rRNA gene sequencing was performed on milk samples collected at 3 (N = 229) and 6 (N = 171) months postpartum from the Infant Fish Oil Supplementation (IFOS) RCT. All mothers in the IFOS cohort have at least one allergic disease or atopy (positive skin prick test). Alpha diversity (Shannon index and richness) and the relative abundance of each bacterial taxa were analysed using linear mixed models. Beta diversity (Bray-Curtis distance) was assess by PERMANOVA.

 

Results

Beta diversity, but not alpha diversity, differed by infant age (3 vs 6 months) (P=0.001). The strongest driver of the milk microbiome in this cohort was season of birth (P=0.001 at 3 months, P=0.016 at 6 months), followed by parity and ethnicity. Season of birth was associated with significant differences in Acinetobacter johnsonii, Enterobacter cloacae, Haemophilus parainfluenzae, Pseudomonas fluorescens, and Acinobacter septicus, as well as beta diversity. Milk microbiome composition also varied significantly in relation to delivery mode, feeding status, parity, lactation stage, infant sex, maternal age, passive smoke exposure, and pets at home, which is in line with previous findings in the healthy population. Interestingly, type of maternal allergy also contributed to the differences between individuals.

 

Conclusion

This is the first study of the human milk microbiome of allergic mothers. Season of birth was the strongest driver of the milk microbiome, with relationships also identified with maternal, infant, and environmental factors. Whether these differences influence infant allergy outcomes requires further analysis.