Relative reduction of biological and phylogenetic diversity of the oral microbiota of diabetes and pre-diabetes patients

Journal Article
Tayeb, Amr T.M. Saeb∗, Khalid A. Al-Rubeaan, Khalid Aldosary, G.K. Udaya Rajac, Balavenkatesh Manic, Mohamed Abouelhodad, Hamsa T. . 2019
Publication Work Type: 
Original Research
Tags: 
Oral microbiota Diabetes Impaired glucose tolerance 16S rRNA Next-generation sequencing Ion torrent
Magazine \ Newspaper: 
Microbial Pathogenesis
Volume Number: 
215–229
Publication Abstract: 

Background: A reciprocal relationship between oral health and systemic disease, such as type 2 diabetes, has
been suggested, whereby a systemic disease is a predisposing factor for oral infection. If the infection occurs, it in
turn aggravates the progression of the systemic disease. According to several studies, certain constituents of the
oral microbiota are linked to diabetes, metabolic syndrome, and obesity. In the current study, we aimed to
compare the microbial diversity and population structure of the oral microbiota of normoglycemic, impaired
glucose tolerance (IGT), and diabetes patients.
Methodology: The study followed a case-control design, with 15 type 2 diabetes patients, 10 IGT subjects, and 19
control subjects. All subjects underwent assessment of periodontitis and oral health. Saliva samples were collected,
and DNA was isolated from these samples. Hypervariable regions of the 16Sr RNA gene were amplified
and sequenced, and the generated sequences underwent bioinformatics analysis. Statistical analysis and diversity
index calculations were made using the statistical software R, vegan R-package, and Past3.20 software.
Results: Overall, 551 operational taxonomic units (OTUs) were identified. Based on OTU analysis, a clear reduction
of the number of species was observed in both IGT (412) and diabetes groups (372) compared with that
in the normoglycemic group (502). This was associated with a similar pattern of reduction of biological diversity
among the three groups. The phylogenetic diversity (PD-SBL) value in the normoglycemic group was higher than
that in the diabetes group. The diabetes group exhibited the highest evenness value and the highest microbiota
bacterial pathogenic content.
Conclusion: A clear reduction of the biological and phylogenetic diversity was apparent in the diabetes and prediabetes
oral microbiota in comparison with that in the normoglycemic oral microbiota. However, this was
associated with an increase in the pathogenic content of the hyperglycemic microbiota. The results of this study
may aid to better understanding of the directionality of the mysterious reciprocal relationship.