Metagenomic Analysis of the Buccal Microbiome by Nanopore Sequencing Reveals Structural Differences in the Microbiome of a Patient with Molar Incisor Hypomineralization (MIH) Compared to a Healthy Child-Case Study.

Abstract

Molar incisor hypomineralization (MIH) is a qualitative developmental defect that affects the enamel tissue of permanent molars and can also occur in permanent incisors. Enamel affected by MIH has reduced hardness, increased porosity, and a higher organic content than unaffected enamel. These characteristics predispose the enamel to accumulation of bacteria and a higher prevalence of caries lesions. Through a groundbreaking metagenomic analysis of the buccal mucosal sample from a patient with MIH, we explored the intricacies of its microbiome compared to a healthy control using state-of-the-art nanopore long-read sequencing. Out of the 210 bacterial taxa identified in the MIH microbiome, we found Streptococcus and Haemophilus to be the most abundant genera. The bacteria with the highest read counts in the patient with MIH included Streptococcus mitis, Haemophilus parainfluenzae, Streptococcus pneumoniae, Rothia dentocariosa, and Gemella haemolysans. Our results revealed a striking contrast between healthy and MIH affected children, with a higher dominance and number of pathogenic species (S. pneumoniae, H. influenzae, and N. meningitidis) and reduced diversity in the MIH-affected patient. This distinct microbial profile not only sheds light on MIH-affected patients, but paves the way for future research, inspiring deeper understanding and larger scale studies.