MEDICAL AND GENETIC STUDIES OF ORAL MICROBIOMA STATUS IN CHILDREN

Abstract

Studies of the structure of bacterial communities of the oral cavity in children is of importance, since periodontal diseases, being one of the main causes of premature tooth loss in adults, develop already in childhood. We studied the bacterial composition of oral microbiota in saliva and supraventricular plaques in 60 children aged 3-6 years with caries and without it. A variety of bacteria in the oral microbiome is represented by the genera Streptococcus, Veillonella, Actinomyces, Granulicatella, Leptotrichia and Thiomonas; in plaques they are closely associated with dental caries (p <0.05). The variety of genes that is revealed in dentin of children with caries is closely associated with a large number of enzymes and taxons in dentin, which is combined with the presence of acidogenic and proteolytic activity and indicates that the development of caries in children is the result of the presence of high acid and proteolytic activity in the oral microbiome. Using PCR analysis, a study of the presence of periodontal pathogens in the oral cavity in children aged six, twelve, eighteen and twenty-four months, in comparison with the microbiota of the oral cavity of their mothers was conducted. A positive correlation was found between mother-child couples in all periods. It is concluded that early inclusion of children in the programs for the prevention and control of oral microbiome can help prevent gaining of aggressive pathogens in the subsequent period of life. Changes in the oral microbiome associated with age for such status of the dentition as milk dentition are shown. During a 2-years’ period preschool children with a full milk dentition were examined. Saliva was collected, an oral examination was carried out every 6 consequtive months. With the development of caries, the structure of the salivary microbial community has changed. The number of genera Atopobium, Megasphaera, and Veillonella has increased, while the number of genera Shuttleworthia and Rothia has decreased. Megasphaera and Veillonella dominated in the early stage of milk dentition, Peptococcus, Rothia and Treponema dominated in the later stage. A study of bacterial and viral associations of saliva and immune resistance in 127 healthy children and adolescents revealed that the bacterial and viral components of the oral fluid microbiota are in dynamic relationship with each other, as well as with immune resistance and can serve as an indicator of the level of health and selection criterion at the stages of clinical examinations of children and adolescents at risk of developing dental diseases. An analysis of the intestinal and oral microbiota in 226 two-year-old children was performed by the method of sequencing 16S rRNA gene. The results suggest that by the age of two years, oral microbiota of children together with a rapid increase in body weight begins to reveal patterns that are often observed in obese adults. Thus, an analysis of the evolution of the microbiota of the oral cavity in a child and changes in its composition are necessary to prevent the development of the disease with age.

Keywords

• children
• oral microbiome
• genetic analysis