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 arthri tis is based mainly on the detection of Chlamydia trachomatis with uro genital swabs or in urine. Because chlamydial antigen, rRNA, and DNA a re present in low quantities in the inflamed joint, highly sensitive a ssays are needed to detect C. trachomatis not only at the primary site of infection but also in peripheral blood and peripheral blood leukoc ytes, 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 o f defined numbers of purified C. trachomatis elementary bodies (EB) in urine, peripheral blood, peripheral blood leukocytes, and synovial fl uid were determined. In urine, PCR detected 2, MicroTrak and Chlamydia EIA 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. trachomat is, 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 rout ine diagnosis of Chlamydia-induced arthritis.