A Study on Blood Microbiome Using 16S rRNA Gene and Sequencing in Rheumatoid Arthritis Patients

Recent studies suggest that bacteria may play a role in triggering rheumatoid arthritis. Considering the recent reports on viable but non-culturable cells (VBNC) in the synovial fluid and blood of patients, the role of bacteria has become more prominent. The present study aimed to use general and specific primers to detect microbiome in the blood of patients with rheumatoid arthritis.

A general primer, called 16S rRNA was used in the present study to detect a wide range of bacteria in the blood of patients with rheumatoid arthritis. Specific primers were designed and used such as nuc and rfbE to trace Staphylococcus aureus and Escherichia coli in patients' blood. Examining 102 blood samples and performing the genomic extraction separately for each sample, PCR was then performed using general and specific primers, and the results were sequenced. The findings were analyzed using descriptive statistics.

According to the results, in 102 blood samples of rheumatoid arthritis patients, who were negative for bacteriological culture, there were 74 cases (72.54%) of 16S rRNA gene, and 54 cases (52.9%) of Staphylococcus aureus nuc gene, respectively. Moreover, a specific gene, rfbE, was traced in 12 samples.

The findings of the present study indicated the presence of microbiome in the blood of patients with rheumatoid arthritis. Because the blast sequencing results of the PCR product showed a wide range of bacterial genomes. These findings may potentially improve the management of rheumatoid arthritis diagnosis and treatment.