Abstract

Background and purpose: Etiology of rheumatoid arthritis is not fully recognized. The purpose of this study was to use universal and specific primers to trace bacteria in the blood and synovial fluid in patients with rheumatoid arthritis. Materials and methods: In this experimental study, a PCR method was developed to identify a wide range of bacteria in general and Staphylococcus aureus in specific. Ninety five synovial fluid and 100 blood samples being stored at -80°C were assayed. Genome extraction was performed. Universal primer pairs were used for amplification of 16SrRNA and a specific primer was used for nuc gene of Staphylococcus aureus. Then, the PCR product of the specific primer was sequenced and data were analyzed. Results: The samples of synovial fluid and blood samples of rheumatoid arthritis patients which were negative in bacteriological culture showed 33 (34) and 36 (36) cases to be positive for 16Sr RNA, respectively. Also, 21 cases of synovial fluid and only 1 blood sample were positive for Staphylococcus aureus. Conclusion: The results showed the presence of 16SrRNA gene of different bacteria, including Staphylococcus aureus in blood and synovial fluid of patients. Based on current findings, it is likely to explain a part of the etiology of rheumatoid arthritis, thereby modifying some treatment protocols. © 2019, Mazandaran University of Medical Sciences. All rights reserved.