[Microbiome of therapeutic muds used in Tatarstan]

Therapeutic muds (peloids), which are widely used for body healing, improve metabolism and have antibacterial, anti-inflammatory and analgesic effects due to enrichment with necessary microelements and biological active substances. However, the microbiological component of these effects is not well studied.

To characterize the microbiome of therapeutic muds, used in the Tatarstan Republic, by identifying spectrum of cultivated microorganisms, using molecular analysis of bacterial communities, and by determining their biodiversity and functional potential based on revealed genetic determinants.

The study design of 5 peloids samples (local sapropels and peat deposits of swamp; 3 samples of Crimean sulfide muds) included three main techniques: isolation and taxonomic determination of cultivated microorganisms by time-of-flight mass-spectrometry; molecular analysis of peloids bacterial communities by 16S RNA high-throughput sequencing; identification of functional profiles of communities by their genetic determinant using Global Mapper tool on iVikodak platform.

Experimental studies have confirmed the safety of examined peloids, where non-pathogenic cultivated bacteria belonging mainly to Bacillus and Rhodococcus genera were dominant. Metagenomic analysis showed that Firmicutes, Proteobacteria and Actinobacteria were predominant in all samples in different ratios. It has been established, that there is both the internal biodiversity of each sample and difference between them. The functional profile of microbial communities was determined based on the identification of bacterial genes. It has been revealed that all communities have an ability to synthesize antibiotics, as well as to decompose dangerous xenobiotics - polyaromatic hydrocarbons, cyclic compounds, and dioxins.

Various microbial communities, which were identified in the therapeutic muds, contribute both to the clearance of toxicants in the peloids and to the antibacterial properties of the latter. The obtained priority results create a fundamental basis for the subsequent study of the role of peloids' microbiome of different origin in their healing action.