THE ORAL MICROBIOTA: SILENT ENEMY OR NECESSARY BACTERIAL TISSUE?

Oral microbe communities have been explored and studied for several decades, and investigations of the role of microorganisms residing in the oral cavity have attracted much attention in these last years, alongside classical human infectious diseases. Numerous studies have reported changes in oral microbiota during not only classical oral bacterial diseases such as periodontitis but also different systemic illnesses. These include: cardiovascular disease, colorectal cancer, rheumatoid arthritis, Alzheimer’s disease, as well as cardiovascular infection and adverse pregnancy outcomes. Oral microbiota is59/74 Journal of Pediatric and Neonatal Individualized Medicine • vol. 8 • n. 2 • 2019 www.jpnim.com Open Access Selected Lectures of the 15th International Workshop on Neonatology • Cagliari (Italy) • October 24th-26th, 2019 mainly located on the tongue dorsum with about 800 different microbial species, and some of these are periodontal pathogens (PP). The study of these Gramnegative anaerobic bacteria linked with inflammatory processes has attracted the attention of researchers outside the oral field, due to the potential influence of these bacteria on the initiation and/or progression of several systemic degenerative diseases. These bacteria could promote the development of systemic diseases in an indirect way, such as toxin production (i.e., LPS) or directly by blood stream-migration with serial transient bacteremias. These occur in some cases following oral tissue injuries after, for example, surgical procedures. Obviously, bacterial accumulation on the tongue and teeth, due to poor oral hygiene and/or host habit factors, smoking and dietary habits could also cause systemic harm to the host. For example, several PPs evade innate immune detection via Toll-like receptor (TLR)-4, facilitating chronic inflammation in different tissues.