Preliminary Evidence for Sex-Specific Trends in Probiotic Modulation of Gut Saccharibacteria in Familial Mediterranean Fever Patients: Effects of Lactobacillus acidophilus INMIA 9602 Er 317/402 and Escherichia coli M-17

Candidate Phyla Radiation bacteria are emerging members of the human microbiota, particularly in oral and gut environments. Saccharibacteria were previously identified in the gut microbiota of healthy individuals and women diagnosed with familial Mediterranean fever (FMF), a monogenic autoinflammatory disorder prevalent in the eastern Mediterranean region, including Armenia. This study aimed to assess the prevalence and diversity of <i>Saccharibacteria</i> spp. and its basebiont <i>Schaalia odontolytica</i> in FMF patients, explore gender differences, and evaluate the modulation potential of two locally produced probiotics: <i>Lactobacillus acidophilus</i> INMIA9602 Er317/402 (Narine^®, VITAMAX-E, Yerevan, Armenia) and <i>Escherichia coli</i> M-17 (Colibacteron^®, VITAMAX-E, Yerevan, Armenia). The abundance and behavior of saccharibacteria and <i>S. odontolytica</i> appear to vary depending on health status and sex. Placebo administration caused both quantitative and qualitative shifts, suggesting a possible interaction between <i>Candidatus saccharibacteria</i> spp. and <i>Schaalia odontolytica</i>, though the underlying biological significance remains to be clarified. Narine administration appeared to increase the abundance of <i>Candidatus saccharibacteria</i> operational taxonomic units (OTUs) in FMF women and <i>S. odontolytica</i> OTUs in FMF men, whereas Colibacteron selectively decreased certain OTUs, predominantly in FMF women. These findings underscore the need to further investigate saccharibacteria's role in systemic inflammation and probiotic-mediated modulation of the gut microbiota.