Detection of mycobacteria in joint samples from patients with arthritis using a genus-specific polymerase chain reaction and sequence analysis

Objective. Mycobacteria have been implicated in the pathogenesis of various forms of arthritis. The aim of this study was to examine the diagnostic po tential of molecular biological techniques as well as to investigate the pa thogenetic role of mycobacteria in chronic arthritis. Patients and methods. DNA, extracted from synovial fluid and synovial tissu e samples from patients with mycobacterial septic arthritis (n = 2), serone gative spondyloarthropathies (SpA) (n = 18), undifferentiated arthritis (UA ) (n = 21) and rheumatoid arthritis (RA) (n = 40), was analysed using a myc obacterial genus-specific polymerase chain reaction (PCR) applied to amplif y mycobacterial DNA. Subsequently, automated sequencing was performed for s peciation. Samples from patients with either non-mycobacterial septic arthr itis, osteoarthritis (OA), crystal arthritis or joint trauma served as nega tive controls (n = 19). Results. mycobacterium tuberculosis complex and Mycobacterium marinum were detected in the two patients with mycobacterial septic arthritis. The other species identified were Mycobacterium hodleri (in one RA patient), Mycobac terium smegmatis (in one OA patient and two RA patients) and Mycobacterium austroafricanum (in one crystal arthritis patient). All other samples were negative. Conclusions. The results suggest that the mycobacterial genus-specific PCR applied on DNA extracts isolated directly from joint samples may be employe d as an additional diagnostic tool in the case of clinical suspicion of a m ycobacterial infection. No evidence was obtained for a pathogenetic role of mycobacteria in SpA, UA or RA.