Objective: To assess the subgingival biofilms in children with asthma with different dental conditions (caries, healthy teeth) by 16S rDNA sequencing.

Material and methods: The sample consisted of eighteen asthmatic children of both sexes aged 3 to 6 years, 10 of them with caries, 8 with a healthy oral cavity. Diagnosis of asthma and assessment of its severity were carried out based on GINA criteria. All children underwent a clinical examination to assess dental caries (decayed, missing, and filled permanent tooth [DMF]). Plaque samples from the caries-free children were obtained by scraping the occlusal surface of the second deciduous mandibular left molar (75) with a sterile metal spoon excavator. Total DNA was extracted from subgingival biofilms. DNA libraries were analysed by 16S rRNA gene sequencing on the MiSeq (Illumina) platform, in the Laboratory for the research of the mechanisms of human microbiocenoses formation, Institute for Cellular and Intracellular Symbiosis, Ural Branch of Russian Academy of Sciences, 11 Pionerskaya Street, Orenburg, 460000, Russia

Results: No significant differences were found in the bacterial community composition between children with or without caries and asthma. Caries-enriched taxa included the classes Actinobacteria and Negativicutes; the orders Selenomonadales and Actinomycetales; the families Veillonellaceae, Micrococcaceae, and Fusobacteriaceae; and the genera Veillonella, Rothia, Fusobacterium, and Streptobacillus. The relative abundances of Veillonella spp., Flavobacterium sp. 1, Leptotrichia hongkongensis, Streptobacillus sp., and Actinomyces viscosus were significantly higher in asthmatic children and caries than in children without caries. Neisseria oralis was significantly higher in caries‐free children with asthma (p < 0.05).

Conclusions: Veillonella was significantly higher in dental caries in children with asthma. The oral cavity of children with asthma is colonized by opportunistic bacteria with high pathogenicity, such as Streptococcus, Neisseria, Veillonella, Prevotella, Haemophilus, Fusobacterium and Porphyromonas, which may be involved in the pathogenesis of both dental caries and asthma.

Keywords: 16S metagenomics, cariogenic bacteria, asthmatic children, oral microbiota.

TBA