Chlamydia trachomatis reinfection rates among female adolescents seeking rescreening in school-based health centers.

BACKGROUND: Chlamydia trachomatis (CT) infections are common among adolescents attending high and middle schools. The study objective was to determine the reinfection rates of CT for females attending school-based health centers. METHODS: Adolescents attending school-based health centers who reported they were sexually active were screened for CT using nucleic acid amplification tests on cervical or urine samples. Between 1996 and 2003, 10,609 female students were tested. The overall annual prevalence for unduplicated students in a calendar year ranged from 15.1% to 19.5%. Reinfection was defined as a positive test result occurring between 30 and 365 days after an initial positive result. RESULTS: There were 897 female students who tested positive for CT and returned for at least 1 subsequent test between 30 and 365 days later. Of these, 236 had 1 or more subsequent positive tests for a cumulative incidence of reinfection in 1 year of 26.3% (95% confidence interval = 23.4-29.2%). Young age at first infection was significantly associated with increased risk of subsequent infection (P <0.01). Across sites, the cumulative incidence of reinfection in these female students ranged from 14.3% to 38.9%. CONCLUSIONS: The chlamydia cumulative incidence of reinfection in these female adolescents attending high and middle schools was high and supports the Centers for Disease Control and Prevention recommendation to screen adolescents frequently, especially those with a history of a previous chlamydia infection.

The microbicide tenofovir does not inhibit nucleic acid amplification tests for detection of Chlamydia trachomatis and Neisseria gonorrhoeae in urine samples.

The potential inhibitory effects of tenofovir and a placebo were examined using the Becton Dickinson ProbeTec, Gen-Probe Aptima Combo 2, and Roche Amplicor tests to detect Chlamydia trachomatis and Neisseria gonorrhoeae. Concentrations of 5% to 0% of tenofovir and the placebo were added to dilutions of C. trachomatis and N. gonorrhoeae. No appreciable inhibition was observed.

Comparison of the urine Leukocyte Esterase Test to a Nucleic Acid Amplification Test for screening non-health care-seeking male soldiers for Chlamydia trachomatis and Neisseria gonorrhoeae infections.

We evaluated the Leukocyte Esterase Test (LET) as a screening tool by testing urine from 1,438 non-health care-seeking male Army basic trainees with LET and a Nucleic Acid Amplification Test. Compared to Nucleic Acid Amplification Test results, LET sensitivity and specificity for detection of chlamydia and gonorrhea were 45.8% and 97.4%, and 60.0% and 96.2%, respectively. The prevalence of chlamydia and gonorrhea was 3.3% and 0.3%, respectively. In this population, the prevalence of gonorrhea was too low to produce reliable estimates of performance characteristics of the LET for gonorrhea. The LET is not warranted for use in screening non-health care-seeking male Army trainees.

Can nucleic acid amplification tests be used to test for chlamydia and gonorrhoea in microbicide trials?

Microbicides may interfere with detection of Chlamydia trachomatis (Ct) and Neisseria gonorrhoeae (Ng) in urine samples from women who use microbicides. The inhibitory effects of BufferGel, PRO2000 and PRO2000 placebo, in urine samples, were determined by nucleic acid amplification tests (NAATs). Uninfected urine was inoculated with different concentrations (10(5)-10(1) organisms/mL); microbicides were added to achieve final concentrations from 5% to 0.1%. Specimens were tested using strand displacement amplification (SDA) for Ct and Ng. Samples with BufferGel demonstrated no inhibition. Samples with PRO2000 showed inhibition at the 5% concentration when tested for Ct, whereas for Ng, PRO2000 showed inhibition at 5%, 2% and some 1% concentrations. The placebo showed no inhibition when detecting Ct, and variable inhibition at the 5% and 2% concentrations for Ng. The potential inhibitory effects of microbicides on the NAATs selected for detection of Ct and Ng should be considered in clinical trials involving topical microbicides.

The use of focus groups to design an internet-based program for chlamydia screening with self-administered vaginal swabs: what women want.

OBJECTIVE: To ascertain the opinions, concerns and perceptions of sexually active women to guide the development of an internet-based chlamydia outreach and screening program using self-administered vaginal swabs as a first step to prevention. METHODS: Seven focus groups were conducted by trained facilitators. Questions were designed to initially open the discussion and elicit the members' own perceptions. Secondary, more probing questions were asked later to confirm participants' responses and elicit truthful answers. The main discussion topics were women's ideas about internet recruitment for chlamydia screening, preferred genital sample type, self-sampling at home using vaginal swabs and using the mail to return specimens. Participants were 42 women, aged 14-49 years. Structured discussions were facilitated using open-ended questions about access to chlamydia testing via the internet. Data were collected and reviewed for common themes and emphasis. RESULTS: All women actively participated in the discussions, providing valuable information. The concepts of self-sampling and the overall project were viewed positively, along with draft advertisements, questionnaires and self-sampling instructions; some modifications were suggested. Common themes included offering free kits available within their community or by direct mail, as well as pre-addressed, stamped mailers for returning the kit to the laboratory for testing. Commonly perceived obstacles and potential risks included: maintenance of confidentiality; situations of embarrassment; and ensuring simplicity of packaging. Women indicated confidence in their ability to collect vaginal specimens and willingness to call for their test results. CONCLUSIONS: Focus-group surveys were a useful tool and provided valuable feedback to inform the design of a specialised website to educate and facilitate access to chlamydia screening through home sampling.

Comparison between the Gen-Probe transcription-mediated amplification Trichomonas vaginalis research assay and real-time PCR for Trichomonas vaginalis detection using a Roche LightCycler instrument with female self-obtained vaginal swab samples and male urine samples.

This study compared two assays for Trichomonas vaginalis detection, Gen-Probe's transcription-mediated amplification (TMA) assay for Trichomonas vaginalis and BTUB FRET PCR, using self-obtained clinical samples from 611 patients. Infection status was defined as two positive results by two different tests. The initial TMA assay sensitivity was 96.7%; specificity was 97.5%. The TMA assay was comparable to BTUB FRET PCR.

Internet-based screening for Chlamydia trachomatis to reach non-clinic populations with mailed self-administered vaginal swabs.

BACKGROUND: Testing for Chlamydia trachomatis by nucleic acid amplification tests (NAATs) using self-collected vaginal swabs (VS) is acceptable and accurate. The objectives were to implement an educational Internet-based program for women to facilitate home screening, to determine whether women would request and use self-collected VS kits, to determine associated risk factors for infection, and to determine satisfaction with the process. METHODS: The website, www.iwantthekit.org, was designed to encourage women > or =14 years to obtain home-sampling kits. Kits could be obtained in the community, requested by Internet/e-mail, or telephone. Users mailed the self-collected VS to the laboratory. Swabs were tested by 3 NAAT assays. Respondents called for results. RESULTS: Forty-one of 400 (10.3%) women were chlamydia positive; 95.1% were treated. Questionnaires indicated 89.5% preferred self-collection, 93.5% rated collection easy/very easy, and 86.3% would use the Internet program again. Black race and age <25 years were associated independently with being chlamydia positive, while use of birth control and non-consensual sex were protective. Thirty-six of 41 (87.8%) positive samples were positive by all 3 NAATs, 5/41 (12.2%) were positive by only 2 NAATs, and none were positive by only 1 NAAT. The Internet/e-mail request method was better than the community pick-up approach because 97.2% of kit requests were e-mailed and 87.5% of kits returned for testing were e-mail requested. CONCLUSIONS: Women will use the Internet to request and use home-sampling kits for chlamydia. NAAT testing performed well on dry-transported VS. High prevalence was detected and questionnaires indicated high-risk sexual behavior.

Chlamydia pneumoniae enhances cytokine-stimulated human monocyte matrix metalloproteinases through a prostaglandin E2-dependent mechanism.

Exposure of human monocytes to Chlamydia pneumoniae resulted in a significant enhancement of matrix metalloproteinase (MMP) 1 and 9 production following stimulation with tumor necrosis factor alpha and granulocyte monocyte-colony stimulating factor. The effect of C. pneumoniae on monocyte MMPs was mediated through the induction of prostaglandin E(2). These findings may have implications for atherosclerotic plaque rupture.

Comparison of three nucleic acid amplification tests for detection of Chlamydia trachomatis in urine specimens.

Traditionally, culture and immunoassays have been performed for the detection of sexually transmitted diseases, including Chlamydia trachomatis. However, these assays may often require invasive specimen collection methods, such as female cervical and male urethral swabs. Recently, nucleic acid amplification tests (NAATs) have been approved for testing for the presence of C. trachomatis in urine samples. Our objective was to compare the sensitivities and specificities of C. trachomatis detection in urine samples with three NAATs: the Abbott LCx (LCx), BD ProbeTec ET (ProbeTec), and Gen-Probe APTIMA Combo 2 (AC2). Urine specimens (n = 506) were collected from both symptomatic and asymptomatic males and females from various high school health clinics. Specimens were tested for C. trachomatis with the three NAATs, and a true-positive result was defined as any two positive NAATs. The C. trachomatis prevalence was 14.8% (75 of 506 samples). Of the 75 urine samples defined as true positives, LCx detected 72, ProbeTec 72, and AC2 detected 75. The sensitivities of LCx, ProbeTec, and AC2 for C. trachomatis detection were 96.0, 96.0, and 100%, and the specificities were 99.1, 100, and 98.8%, respectively. Four of five samples that were positive with AC2 and negative with LCx and ProbeTec were found to be positive with an alternative target TMA-based NAAT, APTIMA C. trachomatis, suggesting that they may have been true positives. Two of four uniquely positive LCx samples available for subsequent testing were both found to be positive by Roche PCR. We found that the LCx, ProbeTec, and AC2 NAATs are highly sensitive and specific methods for the detection of C. trachomatis in urine specimens and can be recommended for noninvasive screening of C. trachomatis in urine.

Is Chlamydia pneumoniae infection associated with stroke in children with sickle cell disease?

BACKGROUND: Stroke is often a devastating complication of sickle cell disease (SCD). Most children with SCD-related stroke have stenotic and occlusive disease of cerebral blood vessels due to intimal hyperplasia. This hyperplasia is hypothesized to result from an inflammatory response similar to that in atherosclerosis and has been attributed to infection by Chlamydia pneumoniae. OBJECTIVE: To determine whether C pneumoniae infection is associated with stroke and cerebrovascular disease, including transient ischemic attacks and abnormal transcranial Doppler examinations, in children with SCD. METHODS: Children with SCD on chronic transfusion due to a history of stroke, transient ischemic attack, or abnormal transcranial Doppler; children with SCD without stroke; healthy controls; and children being transfused for other reasons were enrolled. Peripheral blood and nasopharyngeal (NP) swab specimens were collected from all patients. In patients on transfusion, pretransfusion specimens and samples from the unit of packed red blood cells being transfused were obtained. Peripheral blood monocytic cells (PBMCs) and NP swab specimens were cultured for C pneumoniae in HEp-2 cells. C pneumoniae polymerase chain reaction was performed on PBMCs with a nested touch-down method with primers from the omp-1gene (in duplicate) and a second real-time polymerase chain reaction by using 16S ribosomal RNA primers. RESULTS: C pneumoniae DNA was detected in the PBMCs of 1 of 14 (7.1%) children with SCD on chronic transfusion, 1 of 10 (10%) sickle cell controls, 1 of 10 (10%) healthy controls, and none of the 5 children receiving chronic transfusion for other reasons. It was not detected in specimens from transfusion units. One child with SCD and stroke, 1 sickle cell control, and 1 transfusion control had positive NP cultures for C pneumoniae. C pneumoniae DNA was not detected in their PBMCs, and all 3 children were asymptomatic. C pneumoniae was not detected by culture of PBMCs from any of the patients after 7 passages. CONCLUSION: Stroke in children with SCD does not seem to be associated with C pneumoniae infection in our population.

Real-time PCR for Chlamydia pneumoniae utilizing the Roche Lightcycler and a 16S rRNA gene target.

Chlamydia pneumoniae (CPN) causes pneumonia in humans, and has emerged as an important respiratory pathogen. There are also established links between CPN infection and coronary artery disease. Traditional culture methods for CPN detection can be time consuming and difficult. There are a variety of molecular-based amplification methods for CPN detection. These methods are more sensitive than culture, but have the disadvantage of being inconsistent and non-comparable across studies. In this paper, we describe the adaptation of the existing primer set CPN 90/CPN91 for use in a real-time PCR assay using the Roche Lightcycler and a Taqman probe. This assay had an analytical sensitivity of between 4 and 0.4 infection-forming units (IFUs)/PCR reaction. A total of 355 samples were tested for validation of the assay. Tested samples included two standardized panels of blinded samples from culture (N = 70), archived specimens consisting of a CPN dilution series, CPN-spiked porcine aortal tissue and endarterectomy specimens (N = 87). The third group consisted of prospectively collected PBMCs from clinical samples (N = 198). Results were compared to nested PCR, which targets the ompA gene of CPN; TETR PCR, which targets the 16S rRNA gene of CPN; or the known result for the sample. Overall, the assay had a sensitivity of 88.5% (69 of 78) and a specificity of 99.3% (275 of 277). This method should prove useful for accurate, high throughput detection of CPN.

Comparison of an industry-derived LCx Chlamydia pneumoniae PCR research kit to in-house assays performed in five laboratories.

In a multicenter comparison of PCR assays utilizing 120 quantitated samples of 16 Chlamydia pneumoniae isolates, an LCx research-use-only (RUO) PCR developed by Abbott Laboratories demonstrated 100% sensitivity on 48 samples with >1 copy of DNA per microl of specimen. The sensitivities of five in-house PCR assays ranged from 54 to 94% for the same samples. All six assays showed decreased sensitivities as the DNA copy numbers of the samples decreased. Overall, sensitivities ranged from 68% for the LCx PCR assay to 29% for one of the in-house tests. The LCx RUO PCR and three of the five in-house PCR tests reported no false positives with the 24 negative samples. Increasing the number of replicates tested increased the sensitivities of all of the assays, including the LCx PCR. The LCx RUO assay showed high reproducibility for a single technologist and between technologists, with a kappa agreement of 0.77. The within-center agreements of the five in-house PCR tests varied from 0.19 to 0.74 on two challenges of 60 specimens 1 month apart. The LCx C. pneumoniae RUO PCR shows excellent potential for use in clinical studies, which could enable standardization of results in the field.

Temporal arteritis and Chlamydia pneumoniae: failure to detect the organism by polymerase chain reaction in ninety cases and ninety controls.

OBJECTIVE: To examine the reported correlation between the presence of Chlamydia pneumoniae in temporal artery biopsy specimens and the diagnosis of temporal arteritis (TA). METHODS: Among 90 possible cases of TA identified at our institution between 1968 and 2000, 79 of the positive biopsy specimens (88%) demonstrated giant cells and the other 11 cases (12%) had other histopathologic features compatible with TA; by chart review, all 90 patients were confirmed to have met the American College of Rheumatology classification criteria for TA. Controls had negative temporal artery biopsy specimens during the same 32-year time period and their postbiopsy disease courses were not compatible with TA. Controls were matched with each case by sex, year of biopsy, and age within 10 years. The biopsy specimens from all cases and controls were reevaluated and readings were confirmed in a masked manner by an experienced eye pathologist. Polymerase chain reaction (PCR) analyses for C pneumoniae were performed on the 180 samples using 2 different sets of PCR primers (which target 2 different genes). A primer set targeting the ompA gene (CP1-CP2/CPC-CPD) was used to perform a nested PCR, followed by confirmation of the findings with primers targeting the 16S ribosomal RNA (rRNA) gene (Cpn90/Cpn91) in a touchdown-enzyme time-release PCR. We used positive and negative controls, as well as controls made from infected and noninfected HEp-2 cells, suspended in a formalin-fixed, paraffin-embedded matrix. RESULTS: Seventy-six percent of the 180 cases and controls were women. The mean age of the cases was 72.0 years (range 53-90), and that of the controls was 70.4 years (range 51-86). Eighty percent of the control samples were obtained by temporal artery biopsy performed within 1 year of the biopsies performed on the matched cases. Using the CP1-CP2/CPC-CPD primer set, only 1 TA case sample (1% of all case samples) was positive for the ompA gene. One control sample was also positive using these primers. With the Cpn90/Cpn91 primers, none of the cases and none of the controls were positive for the 16S rRNA gene. CONCLUSION: The results of this study using sensitive and specific PCR analyses do not support a role for C pneumoniae in the pathogenesis of TA.