Some aspects of studying the state of the oral microflora

Abstract

The study of the microflora of the oral cavity plays an important role in establishing the pathogenetic mechanisms of purulent-inflammatory diseases of periodontal tissues. The human oral microbiome includes more than 700 species of microorganisms that inhabit various habitats, including teeth, gums, tongue, cheeks, hard and soft palate, and tonsils. The term "microbiome" was coined in 2001 by Joshua Lederberg to denote the ecological set of commensal, symbiotic and pathogenic microorganisms in our body that play the role of "determinants of health and disease". Under the influence of various factors in the qualitative and quantitative composition of the microflora of the oral cavity there are changes. Her condition is influenced by lifestyle, age, human nutrition, compliance with the rules of oral hygiene, as well as the presence of various diseases, including various disorders and diseases in the oral cavity, and other factors. Because there is a constant flow of microorganisms that enter the oral cavity from the environment, it is necessary to distinguish them from endogenous species, which Theodore Rosebury called local microbes or normal microflora. It is believed that the difference between them cannot be established directly by studies of human isolates alone. It is necessary to compare them with isolates from the external environment to determine which clones are rapidly restored in the host organism, or in the environment. Analysis of the oral microbiome of healthy people using the latest advances in sequencing technology revealed that most species of bacterial microorganisms in healthy people are identical. Based on international research in recent years, a database of phylogenetic data on the human oral microbiome - Human Oral Microbiome Database (HOMD), which includes about 700 taxa (individual species and subgroups) and 13 types of Actinobacteria, Fusobacteria, Chlamidia, Chloroflexi, Furyarchaeota Proteobacteria Spirochaetes, SR1, Synergistetes, Tenericutes and TM7. HOMD is the first phylogenetic base of microbiome results, which aims to understand the health and development of human oral diseases (including caries, purulent-inflammatory periodontal diseases and others). In order to determine the relative number of taxa and to identify new species of oral microbiota, 36,043 clones of 16S rRNA genes with more than 1000 isolates were analyzed. The results revealed 1,179 taxa, of which about 280 species of bacteria were isolated culturally and received an official name, about 8% - cultivated but not named, and 68% were non-cultivated. Thus, it was confirmed that more than half of the species of bacteria existing in the oral cavity cannot be cultured on nutrient media. As for the classical bacteriological methods of research, they are obviously used to the greatest extent in routine practice, to study the state of the human microbiome, including the oral cavity. The search for new methods of prevention and treatment of purulent-inflammatory periodontal diseases is inextricably linked with the isolation of pure cultures of pathogens and the study of their biological properties: sensitivity to antibiotics, exposure to various physical factors (ultraviolet, laser radiation, relativistic electrons, etc.) cells.

DOI: 10.5281/zenodo.4382168