An insight into the fecal microbiota composition in Romanian patients with ankylosing spondylitis using high-throughput 16S rRNA gene amplicon sequencing

Introduction. Application of next-generation sequencing technology generated a massive amount of information on the gut microbiome composition used to understand its role in the healthy state and in various diseases. We aimed to provide information on the gut microbiota composition of Romanian subjects diagnosed with ankylosing spondylitis, an immune-mediated arthropathy linked to a genetic predisposition and gut dysbiosis. Methods. Stool samples collected from 25 patients with ankylosing spondylitis and 16 healthy controls were investigated using high-throughput DNA sequencing of 16S rRNA amplicons from seven different hypervariable regions and Ion Torrent PGM instrument. Microbial composition of metagenomic data was analyzed with QIIME software and differential abundance analysis of taxa encompassed linear discriminant analysis effect size (LEfSe). Results. Overall, 14 phyla, 114 families, 114 genera, and 275 species were identified across the 41 samples, the aggregated data revealing as most abundant the phyla Bacteroidetes, Firmicutes, and Proteobacteria, the families Bacteroidaceae, Prevotellaceae, and Ruminococcaceae, the genera Bacteroides, Prevotella, and Faecalibacterium, and Prevotella copri species. Using various cutoffs for abundance and prevalence, core taxonomic members were identified which in general were shared between the patients and controls. However, evidence was gained that the diversity in the microbiomes from the former cohort was lower than for controls and that certain taxa had significantly different abundance between the two groups. Conclusion. This study allowed an informative high-throughput 16S rRNA profiling of the gut microbiota needed to identify microbiome signatures of risk in the autochthonous population with AS.