The Detection of Mycoplasma spp. DNA in Synovial Fluid of Patients with Inflammatory Arthritis Using PCR-RFLP

Certain Mycoplasma species, the smallest and simplest free-living bacteria which lack a rigid cell wall, are considered as important pathogenic organisms in human and recognized to have a role in rheumatoid arthritis. The aim of this study was to use molecular methods to detect Mycoplasma spp. in synovial fluid of patients with reactive arthritis in comparison with patients suffering from non-inflammatory arthritis as a control group.

Synovial fluid samples were collected from 99 patients with arthritis, all of which fulfilled the standard criteria of American College of Rheumatology for the diagnosis of inflammatory arthritis (59 patients) or non-inflammatory arthritis (40 patients). The DNA of all synovial fluid samples was extracted, and PCR was performed with a specific set of general primers for 16S rRNA of Mycoplasma genus. The PCR products were confirmed via restriction enzyme digestion using BamH1 and sequencing.

A total of 11 out of 99 (11.1%) samples of patients with reactive arthritis revealed a 270bp amplification band. Digesting the PCR product of 16S rRNA by BamH1 confirmed the PCR assay. The sequencing also confirmed the amplified products.

The pathophysiology of inflammatory arthritis could be attributed, at least in part, to the persistence of bacterial DNA in the joint of patients with reactive arthritis.