Microimmunofluorescence (MIF), a Chlamydia trachomatis species-specific enzyme immunoassay incorporating lipopolysaccharide-extracted Chlamydia trachomatis L2 elementary bodies, two different synthetic peptide-based species-specific tests, and a recombinant lipopolysaccharide genus-specific test were performed on multiple follow-up sera (n = 104 total) from 16 women with Chlamydia trachomatis-positive cervical swabs. These women included five with IgG seroconversions, five with Chlamydia trachomatis reinfections after initial therapy, and six with serologic follow-up of more than 6 years after antibiotic therapy. Of all the tests employed in this study, MIF IgG reverted earliest to negative titers, while MIF IgA was the least sensitive. The lipopolysaccharide-extracted elementary body enzyme immunoassay exhibited the closest correlation with the MIF test. The highest test sensitivity was observed in one of the synthetic peptide-based tests, which detected earliest seroconversions and longest IgG persistence. The other synthetic peptide-based test gave false-negative results in 2 of 16 women and did not detect seroconversion earlier than the MIF test. Seroconversion and persistence of genus-specific IgG--cross-reactivity with Chlamydia pneumoniae--against lipopolysaccharide were similar to species-specific IgG. A significant serologic response to reinfection was observed only in women with signs of pelvic inflammatory disease. Species-specific tests of high sensitivity and reproducibility are best suited for gynecological diagnostic purposes.
The following study was conducted to determine whether there would be an effect on the prevalence of Chlamydia trachomatis if both partners in a sexual relationship, rather than only one, underwent screening. First-void urine samples were collected from 1,690 asymptomatic women (mean age, 30 years; range, 15-70 years) and their male sex partners (mean age, 33 years; range, 16-71 years). The duration of sexual partnership for these subjects ranged from 2 months to more than 10 years.. At the time of testing, 687 of the women were pregnant. Ligase chain reaction testing revealed that 42 (2.5%) female and 63 (3.7%) male urine samples were positive. Detection rates for Chlamydia trachomatis differed for males and females, a difference that was found to be significant (P<0.0046, McNemar chi-square). Both partners tested positive in 27 (1.6%) couples, whereas at least one partner tested positive in 78 (4.6%) couples. Thus, screening males for Chlamydia trachomatis would have identified 63 (81%) of these 78 couples compared with only 42 (54%) couples had females been screened exclusively. In standard clinical practice, women most often undergo screening. The results of this study underscore the need to screen both males and females for Chlamydia trachomatis.
The ImmunoComb Chlamydia trachomatis IgG/IgA (Orgenics, Israel) is a new serologic test using C. trachomatis L2 elementary bodies (Washington Research Foundation, Seattle) as antigen. The Ipazyme IgG/IgA test (Savyon, Israel) employs whole cells with C. trachomatis L2 inclusions, i.e. elementary and reticulate bodies. Theoretically, the ImmunoComb is expected to be less cross-reactive (LPS) with Chlamydia pneumoniae than the Ipazyme (LPS and reticulate body group specific antigens). Compared with the Ipazyme, the ImmunoComb IgA showed both a higher positive predictive value (36% versus 25%) and sensitivity (67% versus 33%) for antigen detection in a control group of 100 post partum women with a 6% prevalence of C. trachomatis positive cervical smears. In sterility patients (45 cases with occluded and 53 with open fallopian tubes) the tube status was predicted by the ImmunoComb (Ipazyme) with 74% (72%) positive predictive value, 87% (80%) sensitivity, and 87% (81%) negative predictive value. IgG/IgA prevalence in 118 patients with C. trachomatis positive cervical smears was 85%/55% for the ImmunoComb and 84%/49% for the Ipazyme. The ImmunoComb is considerably faster and easier in handling and less subjective in reading than the Ipazyme.
A total of 276 cervical swabs (241 from first visits and 35 from follow-up visits) from 241 women were tested for Chlamydia trachomatis by polymerase chain reaction (PCR) and enzyme immunoassay (EIA). Sixty-one smears (53 from first visits and 8 from follow-up visits) from 53 women were stained by direct fluorescent antibody (DFA). Twenty-one (8.7%) women had positive swabs in at least two different tests. All follow-up swabs (collected between 3 days and 3 weeks after the first clinical visit) were positive in at least one test when the woman had been positive at the first visit and no antibiotic treatment had been initiated. Including swabs from follow-up visits and DFA results, the respective sensitivities and specificities of the assays were as follows: PCR, 75.9% and 100%; EIA, 69% and 98.4%. The seven swabs that were false negative by PCR (tested initially after thawing from -20 degrees C) were mailed nonrefrigerated to the assay manufacturer, where they tested true positive. These data point to labile inhibitors of the PCR, predominantly cervical mucus.
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