Epidemiology and natural history of ligase chain reaction detected chlamydial and gonococcal infections.

OBJECTIVES: Ligase chain reaction (LCR) technology has dramatically increased the sensitivity of tests for sexually transmitted infections (STIs). It is unknown whether low copy infections (LCR positive, culture negative) have any clinical consequences. We assessed the clinical significance of untreated low copy Chlamydia trachomatis and Neisseria gonorrhoeae infections in a cohort of sexually active women. METHODS: We studied a cohort of sexually active women followed at 6 month intervals for up to 3 years. Frozen urine specimens from 181 women with negative cultures for C. trachomatis and N. gonorrhoeae who were 'high risk' (defined as being less than 40 years old at baseline, and having either Trichomonas vaginalis at baseline or a history of more than one sexual partner during the 12 months before baseline) were tested for C. trachomatis and N. gonorrhoeae by LCR (Abbott Laboratories, Abbott Park, IL, USA). The specimens from all visits for each person were pooled and LCR was performed on the pool. Laboratory results were linked to clinical information. We also tested all urine samples obtained from patients with a positive culture. RESULTS: 10 additional infections (nine C. trachomatis and one N. gonorrhoeae) were detected with LCR technique. None of the women with low copy infection had evidence of subsequent pelvic inflammatory disease or ectopic pregnancy. Pooling of urine samples resulted in a 47% decline in the number of tests performed. CONCLUSIONS: Additional STIs can be identified when using LCR. Pooling of urine specimens is a cost saving technique for C. trachomatis and N. gonorrhoeae testing.

Ability of the digene hybrid capture II test to identify Chlamydia trachomatis and Neisseria gonorrhoeae in cervical specimens.

The Digene Hybrid Capture II (HCII CT/GC) test is a combination test designed to detect Chlamydia trachomatis and Neisseria gonorrhoeae in a single specimen. It is a nucleic acid hybridization test which uses signal amplification to increase sensitivity. We compared its performance to that of culture on cervical specimens from 1,370 women. Direct fluorescent-antibody assay was used to resolve discrepant results for C. trachomatis. Samples were collected with a proprietary cervical brush or with endocervical swabs. The HCII CT/GC test proved to be sensitive and specific in detecting these organisms. Compared to N. gonorrhoeae culture, it had a sensitivity of 93% (87/94) and a specificity of 98.5% (1,244/1,263). Compared to C. trachomatis culture, the sensitivity was 97.7% (129/132) and specificity was 98.2% (1,216/1,238). Testing of some specimens with discrepant results by PCR suggested that the test would actually prove to be even more specific if it were compared to a nucleic acid amplification test (NAAT). The sensitivity of C. trachomatis culture was somewhat less, at 88.6% (117/132). The endocervical brush appeared to be better than Dacron swabs for collecting specimens. The HCII CT/GC test offers an attractive format that allows simultaneous detection of C. trachomatis and N. gonorrhoeae with a single specimen. An initial positive result is followed by repeat tests with probes to identify chlamydiae or gonococci. This test is more sensitive than C. trachomatis culture and is at least as sensitive as culture for gonococci. It deserves further evaluation and comparison with NAATs and may well offer an attractive alternative for diagnosis and screening of these infections.

Small synthetic ligands of the cholecystokinin-B/gastrin receptor can mimic the function of endogenous peptide hormones.

The gastric cholecystokinin-B/gastrin receptor (CCK-BR) is a key regulator of enterochromaffin-like cell function and proliferation. Over the last decade, a number of small non-peptide CCK-BR "antagonists" have been discovered. Here, we demonstrate that some of these non-peptide ligands in fact possess significant ability to activate the human CCK-BR, and are, therefore, more properly categorized as partial agonists. When tested in COS-7 cells transiently expressing the recombinant human CCK-BR, saturating concentrations of the small "peptoid" ligands PD 135,158 and PD 136,450 stimulated inositol phosphate formation to 23 and 43 percent, respectively, of the maximum response induced by a considerably larger endogenous peptide agonist, cholecystokinin octapeptide. In contrast, the benzodiazepine-derived CCK-BR ligand, YM022, acted as a "true" high-affinity antagonist of cholecystokinin-induced inositol phosphate formation (pA2 = 9.69). Consistent with recent findings in animal experiments, our data reveal that small synthetic ligands have the potential to function as either CCK-BR agonists or antagonists. These dual properties of synthetic molecules must be considered when evaluating candidate drugs for human disease.

Comparison of methods for the detection of treponema pallidum in lesions of early syphilis.

BACKGROUND: The clinical diagnosis of primary and secondary syphilis can be difficult because of the wide variability of lesions. The available laboratory tests (dark-field microscopy and direct fluorescent antibody) require specialized microscopes and skilled technicians, and serologic tests are insensitive in early infection. METHODS: Dark-field microscopy and monoclonal antibody staining were compared to a new solid-phase enzyme-linked immunosorbent assay (Visuwell test) for detection of T. pallidum in lesion exudate of 188 patients with genital lesions. RESULTS: Sixty-four patients (34%) had lesions of early syphilis diagnosed by either dark-field, monoclonal antibody staining, or both. The Visuwell test and dark-field examination were positive in 52 (81.3%) and 55 (85.9%) of the 64 patients, respectively, whereas the monoclonal antibody staining technique demonstrated the presence of T. pallidum in 59 (92.2%) of the 64 patients. The Visuwell test gave a negative result in 111 of 124 patients who had negative dark-field and direct fluorescent antibody test results (89.5% specificity). CONCLUSIONS: The Visuwell test is an alternative method for evaluating genital ulcers but is less sensitive and specific than existing tests.

Evaluation of a deoxyribonucleic acid probe for the detection of Trichomonas vaginalis in vaginal secretions.

OBJECTIVE: Our purpose was to compare Affirm VP, a new deoxyribonucleic acid probe test, with standard "wet preparation" microscopic examinations and culture for the identification of Trichomonas vaginalis organisms in vaginal secretions. STUDY DESIGN: We examined vaginal samples from 615 women with symptoms or signs of vaginitis for T. vaginalis using the deoxyribonucleic acid probe test, microscopic examination of wet preparations of vaginal secretions, and culture in modified Diamond's medium. RESULTS: T. vaginalis was identified in specimens from 95 (15.4%) of the 615 patients. Cultures in Diamond's medium identified 93 (98%) of the 95 infected patients. Vaginal wet preparation identified 76 (80%) of the infected women. The deoxyribonucleic acid probe test detected 86 (90.5%) of the 95 infected patients. There was one false-positive deoxyribonucleic acid probe test (specificity 519/520: 99.8%). CONCLUSION: The Affirm VP deoxyribonucleic acid probe test had a sensitivity of 90% and a specificity of 99.8% for the identification of T. vaginalis organisms in women with symptoms with a high prevalence of trichomoniasis. Such a nonculture test may be of considerable benefit in diagnosing T. vaginalis infections, especially in settings where microscopy, culture, or both are unavailable, inconvenient, or unreliably performed.

Identification of mycoplasmas in urine from persons infected with human immunodeficiency virus.

Voided urine samples from persons with and without human immunodeficiency virus (HIV) infection were examined for mycoplasmas. Mycoplasma hominis organisms were identified in cultures of urine from 32 (18%) of 180 HIV-positive individuals and from 8 (21%) of 38 HIV-negative individuals. In contrast, glucose-utilizing mycoplasmas were identified in the urine of 30 (17%) of the HIV-positive individuals and in none of those who were HIV-negative. Assays of growth inhibition around disks containing specific antisera identified 14 of the 30 glucose-utilizing mycoplasmas as Mycoplasma fermentans. Four isolates were presumptively identified as Mycoplasma pirum. Growth on solid media was insufficient to permit the identification of the species of the other 12 isolates by growth inhibition.