Poster Presentation ESA-SRB-ANZBMS 2024 in conjunction with ENSA

Type 2 diabetes mellitus status, sample type and timepoint in gestation interact in the determining the composition of the oral microbiome in pregnancy (#462)

Sophie M Leech 1 , Emily Dorey 2 , Thomas P Mullins 2 , Helen L Barrett 3 4 , Marloes Dekker Nitert 1
  1. School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
  2. Mater Medical Research Institute, South Brisbane, QLD, Australia
  3. Obstetric Medicine, Royal Hospital for Women, Randwick, NSW, Australia
  4. Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia

The oral microbiome is thought to be important for not only oral health, but systemic health, with poor oral health linked with increased risk of developing certain cancers, cardiovascular disease, dementia and diabetes. Additionally, poor oral health is associated with increased risk of adverse pregnancy outcomes, with oral health often worsening during pregnancy. A number of studies have previously investigated the link between gestational diabetes and the oral microbiome; however, no previous studies have investigated the relationship between pre-existing Type 2 diabetes mellitus (T2DM) and the oral microbiome in pregnancy, which is becoming more common. Therefore, in this study we aimed to address this gap by investigating two oral microbial niches at two timepoints during pregnancy in normoglycemic controls and women with pre-existing T2DM.

Buccal swab and saliva rinse samples from 11 women with pre-existing Type 2 diabetes mellitus and 28 normoglycemic controls were collected at two timepoints between 26- and 38-weeks’ gestation. The profile of the saliva microbiome was assessed from shotgun metagenomic sequence data. Community composition was assessed using MetaPhlAn 4.0.6 and functional analysis was conducted with HUMAnN 3.6. Analysis was conducted with GraphPad Prism 9.0.2. and RStudio packages ‘phyloseq’, ‘Mixomics’, ‘vegan’, ‘ANCOM-BC2’ and ‘Maaslin2’.

Saliva rinse microbiomes were largely unchanged by diabetes status but varied across gestation with increases in richness and a number of differentially abundant species between timepoints. In contrast, buccal swabs were altered by diabetes status but minimally by gestation with increased richness in T2DM and increased abundance of Fusobacterium nucleatum SGB6013, GGB4333 SGB5935 (Family Mycoplasmataceae), and GGB1221 SGB1590 (family Prevotellaceae) after adjustment for BMI.

Overall, our results highlight the importance of considering both sample type and timepoint in gestation for oral microbiome studies and its associations with pregnancy outcomes in women with and without T2DM.