Exploring Oral Microbiome in Healthy Infants and Children: A Systematic Review

Abstract

Recent advances in the development of next-generation sequencing (NGS) technologies, such as the 16S rRNA gene sequencing, have enabled significant progress in characterizing the architecture of the oral microbiome. Understanding the taxonomic and functional components of the oral microbiome, especially during early childhood development, is becoming critical for identifying the interactions and adaptations of bacterial communities to dynamic conditions that may lead to the dysfunction of the host environment, thereby contributing to the onset and/or progression of a wide range of pathological conditions. We aimed to provide a comprehensive overview of the most recent evidence from studies of the oral microbiome of infants and young children, focusing on the development of oral microbiome in the window of birth to 18 years, focusing on infants. A systematic literature search was conducted in PubMed, Scopus, WOS, and the WHO clinical trial website for relevant articles published between 2006 to 2022 to identify studies that examined genome-wide transcriptome of the oral microbiome in birth, early childhood, and adolescence performed via 16s rRNA sequence analysis. In addition, the references of selected articles were screened for other relevant studies. This systematic review was performed in accordance PRISMA guidelines. Data extraction and quality assessment were independently conducted by two authors, and a third author resolved discrepancies. Overall, 34 studies were included in this systematic review. Due to a considerable heterogeneity in study population, design, and outcome measures, a formal meta-analysis was not carried out. The current evidence indicates that a core microbiome is present in newborns, and it is stable in species number. Disparity about delivery mode influence are found. Further investigations are needed.

Investigation of periodontal disease development and Porphyromonas gulae FimA genotype distribution in small dogs

“…In recent years, researchers have focused on the timing of the establishment of bacteria that comprise the human oral biofilm 12 . Dysbiosis of the human oral microbiome is detrimental to health, leading to periodontal disease.…”

Novel Clustering Methods Identified Three Caries Status-Related Clusters Based on Oral Microbiome in Thai Mother–Child Dyads

“…A review of the literature in this field agrees with this conclusion, noting that infant microbial diversity is significantly lower than in their parents, but maintains that there is a significant association between the mother’s oral microbiome and her infant’s [ 25 ]. Interestingly, another review notes that children with a higher heterogeneity in their oral microbiomes have lower rates of caries incidence [ 26 ].…”

Influence of maternal oral microbiome on newborn oral microbiome in healthy pregnancies

“…In relation to healthy pregnancies, two main pathways are currently considered: by blood, through the placenta after translocation from the digestive tract (oral cavity and intestines) or by vertical trasmission from the vaginal tract. A recent systematic review summarize studies on oral microbiome in infants, children and adolescents: evidence indicate that a stable core microbiome is present just in newborns and it becomes more differentiated within the first four years of life [ 20 ].…”

“…A so low microbiological density in the mouth of the full term babies immediately after birth could also effort the consideration that, even if the the foetal microbiome colonization may begin already in utero, oral microbiome composition matures throughout the first period of life and it is shaped by factors including host genetics and the enviroment [ 14 ]. Microbiome is a dynamic ecosystem and most of the development of the composition and function of the child’s oral microbiome occurs in the first years [ 20 ] and in particular probably just in the first hours of life [ 3 , 4 , 24 ]. So, the contact with the mother and our interventions on the environment around the mother and the newborn just after birth are very important for future richness and composition of the infant oral microbiome: the initial microbial exchanges between mother and infant at birth are fundamental as these early colonisers play a very important role in the development of the neonate’s immune system and long term in the activity and function of the microbiome [ 25 ].…”