Bacterial DNA in synovial fluid cells of patients with juvenile onset spondyloarthropathies

Objective. To identify bacterial DNA in synovial fluid cells of patients with active juvenile onset spondyloarthropathy (SpA). Methods. The main group of study constituted 22 patients with juvenile onset SpA. In addition, five patients with adult onset SpA and nine with rheumatoid arthritis (RA) were studied. Polymerase chain reaction (PCR) with either genus- or species-specific primers was performed on synovial fluid cells to detect DNA sequences of Chlamydia trachomatis, Yersinia enterocolitica. Salmonella sp., Shigella sp., Campylobacter sp. and Mycobacterium tuberculosis. The presence of antibacterial antibodies in sera and synovial fluid was also determined by enzyme-linked immunoassay. Results. The synovial fluid of nine patients with juvenile onset SpA, three with adult onset SpA and one with RA contained bacterial DNA. Five juvenile onset SpA samples had DNA of one single bacterium, two juvenile onset SpA and three adult onset SpA had DNA of two bacteria and two juvenile onset SpA had DNA of three bacteria. Overall. Salmonella sp. DNA was detected in seven synovial fluid samples, Shigella sp., Campylobacter sp. and M. tuberculosis were found in four samples each, and C. trachomatis was found in two. The bacterial DNA findings correlated with neither diagnosis nor disease duration. One RA synovial fluid had DNA of Campylobacter sp. Neither serum nor synovial fluid antibacterial antibodies correlated with DNA findings or clinical diagnosis. Conclusion. In this study, single and several combinations of bacterial DNA were identified in the synovial fluid of patients with long-term undifferentiated and definite juvenile onset SpA and adult onset SpA. Of relevance is that bacterial DNA corresponds to bacteria producing endemic disease in our population.