Oral microbial dysbiosis in patients with Kostmann syndrome.

PURPOSE: The oral microbiome is maintained by host- and microbe-derived factors. A shift in microbial composition, as a result of diseases related to the immune system, is the most important step in the development of oral and dental diseases. The aim of this study was to investigate the oral microbial composition of patients with Kostmann syndrome, who have severe neutropenia, compared with healthy children.

METHODOLOGY: A group of nine Kostmann syndrome patients and a group of nine healthy controls participated. After clinical investigation, DNA from stimulated saliva specimens was examined by high-throughput sequencing of the V3-V4 hypervariable region of the 16S rRNA gene using Illumina sequencing. The QIIME software package was used for 16 S rRNA amplicon analysis, while the Greengenes database was used for taxonomic classification.

RESULTS: The periodontal pocket depths, plaque indices and bleeding-on-probing percentages and caries status on the deciduous teeth of the patients with Kostmann syndrome were statistically higher than those for the healthy controls. Patients with Kostmann syndrome had significantly lower bacterial diversity as compared to the controls. The presence of Firmicutes was statistically higher in patients with Kostmann syndrome, while that for Proteobacteria was higher in samples from the healthy controls (P<0.05). Streptococcus, Rothia, Granulicatella, Actinomyces, and genera from the family Gemellaceae were present as the core microbiome (abundance >1 % in at least 75  % of samples) in all groups, whereas the genus Porphyromonas was only detected as a member of the core microbiome in Kostmann patients.

CONCLUSIONS: The evidence of lower bacterial diversity and differences in microbial profile for patients with Kostmann syndrome not only shows the impact of immune system-related diseases on oral microbiota, but also endorses the ecological plaque hypothesis proposed for the aetiology of oral diseases such as dental caries and periodontitis.