Objective: Difficulties in detecting Chlamydia trachomatis in human joints by polymerase chain reaction (PCR) may be related to whether synovial tissue or synovial fluid (SF) is used as the source of DNA in PCR amplification. In this study, a new PCR assay was developed and used to compare chlamydial DNA in paired samples of SF and synovial tissue from patients with arthritis.
Methods: The PCR assay targeted the ribosomal RNA operons, which are present in 2 copies on the C trachomatis chromosome. DNA from several relevant bacteria and chlamydial serovars was used for testing this screening system. The detection of chlamydial DNA in nucleic acid preparations from matched samples of SF and synovial tissue was compared by PCR assay. Samples were obtained from 55 patients, including patients with reactive arthritis, Reiter's syndrome, and other arthropathies.
Results: Testing of the PCR screening system confirmed it to be highly specific and sensitive. Use of this assay to screen DNA from SF and synovial tissue samples showed that 29 (53%) of 55 synovial tissue preparations were positive for chlamydial DNA, but only 16 (29%) of the matched SF samples from these 29 patients were similarly positive. Five (9%) of 55 SF samples, but not their tissue counterparts, were positive for chlamydial DNA by PCR.
Conclusion: Detection of chlamydial DNA in the joints of patients by PCR gives positive results more often when synovial tissue rather than SF is the source of target nucleic acids. Although synovial tissue is the source of choice for the most reliable determination of chlamydia in the joint, both synovial tissue and SF should be assayed if possible.