Impact of High altitude environment on human oral microbial community

The human oral microbiota continues to change phenotype by many factors (e.g. environment, host diet, stress etc.), suggesting that oral health or disease depends on the interface between the host and the microbial community as a whole. Amongst one such factor is, extreme environmental condition like High Altitude (HA) - very unique, difficult and full of health risk for visiting population such as mountaineers, bikers, visitors, pilgrims, soldiers and special task forces. However, the reason how the constellation of extreme environmental conditions at HA alter the oral microbiota and its impact on composition, remains unclear. In this study we investigated the influence of HA (4420 m) on the oral microbiota composition by using 16S rRNA metagenomic approach to determine the variation in the oral microbiota. Saliva samples were collected at two different heights i.e., H1 at sea level (210m) and H2 (4420m) after staying for 6 months at H2. Samples were analysed for 16S rRNA sequencing. The oral microbial diversity of human oral cavity was significantly altered with the abundance of several bacteria, during the stay at HA. The oral microbiota comprised mainly of the phyla Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria at both the time points. Further, the differential analysis of microbes at phylum and genus level, showed altered abundance at H2 with respect to H1. In addition, the comparative analysis of microbial metabolic profiles between H1 and H2 showed a significant decrease in functional genes, including two major metabolic pathways involving carbohydrates, and amino acids.