SENSITIVITIES OF PCR, MICROTRAK, CHLAMYDIAEIA, IDEIA, AND PACE-2 FOR PURIFIED CHLAMYDIA-TRACHOMATIS ELEMENTARY BODIES IN URINE, PERIPHERAL-BLOOD, PERIPHERAL-BLOOD LEUKOCYTES, AND SYNOVIAL-FLUID

Routine microbiological diagnosis of Chlamydia-induced reactive arthritis is based mainly on the detection of Chlamydia trachomatis with urogenital swabs or in urine. Because chlamydial antigen, rRNA, and DNA are present in low quantities in the inflamed joint, highly sensitive assays are needed to detect C. trachomatis not only at the primary site of infection but also in peripheral blood and peripheral blood leukocytes, which are suspected carriers for dissemination, and in synovial fluid. To evaluate possible tools for this purpose, the sensitivities of PCR, MicroTrak, ChlamydiaEIA, IDEIA, and PACE 2 for the detection of defined numbers of purified C. trachomatis elementary bodies (EB) in urine, peripheral blood, peripheral blood leukocytes, and synovial fluid were determined. In urine, PCR detected 2, MicroTrak and ChlamydiaEIA detected 2 x 10(3), and PACE 2 and IDEIA detected 2 x 10(4) EB per ml. In peripheral blood, only PCR and MicroTrak detected C. trachomatis, with detection limits of 100 and 2 x 10(7) EB per mi, respectively. For peripheral blood leukocytes, the detection limits were 2 EB per ml for PCR and 2 x 10(4) EB per ml for MicroTrak, ChlamydiaEIA, IDEIA, and PACE 2. In synovial fluid, PCR detected 200, MicroTrak and IDEIA detected 2 x 10(5), and PACE 2 detected 10(6) EB per ml. ChlamydiaEIA was unable to detect 2 x 10(6) EB per mi in synovial fluid. In summary, PCR was found to be the most sensitive method. The sensitivities of the other methods tested were at least 1,000 times lower than that of PCR. PCR should therefore be considered a most promising tool for routine diagnosis of Chlamydia-induced arthritis.