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- Cordioli, Maddalena, et al.
(författare)
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Clinic-based evaluation of the dual Xpert CT/NG assay on the GeneXpert System for screening for extragenital chlamydial and gonococcal infections amongst men who have sex with men
- 2024
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Ingår i: BMC Infectious Diseases. - : BioMed Central (BMC). - 1471-2334. ; 24:Suppl 1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections have increased globally. Asymptomatic infections represent a significant risk of long-term complications. Men who have sex with men (MSM) are disproportionally affected, underscoring the need to offer screening programmes to this population. CT/NG Point of Care Testing (POCT) constitutes a strategic tool to improve the continuum of STI care, however extensive real-life evaluations amongst at risk populations are lacking. The aim of this study is to estimate the GeneXpert CT/NG assay performance and usability for CT and NG at genital and extragenital sites for screening amongst MSM.METHODS: This study was a multi-site sexual health clinic-based evaluation (Italy, Malta and Peru) with consecutive enrolment. A first void urine sample (divided in two aliquots), two oropharyngeal and two anorectal swabs were collected for each study participant. One specimen set (one for each anatomical site) was tested with the dual index test (Cepheid) at the clinics by the healthcare staff, the other set with FDA/CE approved Nucleic Acid Amplification Tests (NAATs) at the laboratory. Clinical sites and reference laboratories participated in an internal and external quality control programme. Sensitivity, specificity, positive and negative likelihood ratios, positive and negative predictive values for each anatomical site were estimated using a meta-analytic approach.RESULTS: One thousand seven hundred two MSM were recruited across all clinical sites for a total of 5049 biological specimens. NG and CT were respectively detected in 274 and 287 of samples. Overall, the NG POCT sensitivity and specificity was 91.43% and 99.75% in urine (LR + 372.80, LR- 0.09), 89.68% and 99.55% in rectal specimens (LR + 197.30, LR- 0.10) and 75.87% and 98.77% at the pharynx respectively (LR + 61.94, LR- 0.24). The CT component of the POCT sensitivity was 84.82% and specificity 99.63% in urine (LR + 228.68, LR- 0.15), 78.07% and 99.19% respectively on rectal site (LR + 96.23, LR-0.22), 67.79% and 99.88% respectively at pharyngeal site (LR + 554.89, LR- 0.32). 95.95% of MSM reported to be willing to wait for POCT results and no provider reported difficulties in terms of performance or interpretation of the results of the Xpert CT/NG.CONCLUSION: Rapid turnaround time, ease of use and high acceptability make the Xpert CT/NG testing system a strategic tool for increasing testing frequency, reaching those not yet tested and offering the possibility of immediate treatment if needed. The assay showed good negative likelihood ratios and confirms its use to rule out CT/NG infections. Sensitivity varied across sites and pathogens. Periodic staff training at the testing sites should be mandatory.
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- Cordioli, Maddalena, et al.
(författare)
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Standardised protocol for a prospective international multicentre clinical-based evaluation of point-of-care tests for the screening of genital and extragenital chlamydial and gonococcal infections in men who have sex with men and for the screening of genital chlamydial, gonococcal and Trichomonas vaginalis infections in at risk women
- 2024
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Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 14:6
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: In 2016, WHO estimated there were roughly 374 million new infections among adults of the following four curable sexually transmitted infections (STIs): chlamydia (caused by Chlamydia trachomatis (CT)), gonorrhoea (Neisseria gonorrhoeae (NG)), syphilis (Treponema pallidum) and trichomoniasis (Trichomonas vaginalis (TV)). Accurate point-of-care tests (POCTs) for screening of genital and extragenital CT, NG and TV infections are of great value and have been developed during recent decade. Several tests are commercially available and have shown encouraging performance compared with 'gold-standard' reference tests in laboratory-based studies. However, there is limited data on their clinical performance, including at the POC. Key populations, such as men who have sex with men (MSM), are at higher risk of these STIs at genital and extragenital sites and these STIs are often asymptomatic, especially in extragenital sites and in women. We will conduct a clinical-based evaluation to assess the performance characteristics and acceptability to end-users of molecular-based diagnostic technology for POC/near patient use of the Xpert CT/NG (Cepheid, Sunnyvale, California, USA) test for screening of genital, anorectal and pharyngeal CT and NG infections in MSM and the Xpert CT/NG and Xpert TV (Cepheid, Sunnyvale, California, USA) for screening of genital CT, NG and TV among women at risk for these STIs compared with gold-standard reference nucleic acid amplification tests. This master protocol outlines the overall research approach that will be used in seven countries.METHOD AND ANALYSES: Consecutive MSM and women at risk presenting at the clinical sites in high, and low- and middle-income countries will be enrolled. The POCTs to be evaluated are Xpert CT/NG and Xpert TV. All procedures will be carried out by trained healthcare staff and tests performed in strict accordance with the manufacturer's instructions. The sensitivity, specificity, positive and negative predictive values for each POCT will be calculated. The study is ongoing with recruitment expected to be completed in all countries by mid-2022 to late-2022.ETHICS AND DISSEMINATION: Prior to enrolment, this core protocol was independently peer-reviewed and approved by the research project review panel (RP2) of the WHO Department of Sexual and Reproductive Health and Research and by the WHO Ethics Review Committee (ERC). The core protocol has been slightly adapted accordingly to individual countries and adaptations approved by both RP2 and ERC, as well as all relevant institutional review boards at each participating site. Results will be disseminated through peer-reviewed journals and presented at relevant national/international conferences.
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- Gios, Lorenzo, et al.
(författare)
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A multi-country comparative study of two treponemal tests for the serodiagnosis of syphilis amongst men who have sex with men (MSM) : Chemo-luminescent assay vs Treponema pallidum particle agglutination assay
- 2024
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Ingår i: BMC Infectious Diseases. - : BioMed Central (BMC). - 1471-2334. ; 24:Suppl 1
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: International guidelines recommend routine screening for syphilis (aetiological agent: Treponema pallidum subspecies pallidum) amongst key populations and vulnerable populations using tests detecting treponemal and non-treponemal antibodies. Whilst treponemal tests have high sensitivities and specificities, they differ regarding subjective or objective interpretation, throughput and workload. Chemiluminescence immunoassays (CLIAs) are cost- and time-effective automated methods for detecting treponemal antibodies. The Treponema pallidum particle agglutination assay (TPPA) has been considered the "gold standard" treponemal assay, however, this includes a highly manual procedure, low throughput and subjective interpretation. The present multi-country study evaluated the ADVIA Centaur® Syphilis CLIA (Siemens Healthcare) assay compared to the reference SERODIA-TP·PA® (Fujirebio Diagnostics) for the serodiagnosis of syphilis amongst men who have sex with men (MSM).METHOD: 1,485 MSM were enrolled in Brighton (UK), Malta, and Verona (Italy) as part of a larger WHO multi-country and multi-site ProSPeRo study. Ethical approval was obtained. Serum was tested with the ADVIA Centaur® Syphilis CLIA assay and SERODIA-TP·PA®, in accordance with the manufacturers' instructions, for a first round of validation. A second round of validation was carried out for discrepant results that were additionally tested with both Western Blot (Westernblot EUROIMMUN®) and an Immunoblot (INNO-LIA, Fujirebio Diagnostics). Sensitivity, specificity, positive and negative predictive value (PPV and NPV), likelihood ratios (positive/negative), and the Diagnostic Odds Ratio (DOR)/pre-post-test probability (Fagan's nomogram) were calculated.RESULTS: Out of 1,485 eligible samples analysed in the first phase, the SERODIA-TP·PA® identified 360 positive and 1,125 negative cases. The ADVIA Centaur® Syphilis CLIA assay (Siemens) identified 366 positives, missclassifying one TPPA-positive sample. In the second phase, the ADVIA Centaur® Syphilis CLIA resulted in 1 false negative and 4 false positive results. Considering the syphilis study prevalence of 24% (95% CI: 22-26.7), The sensitivity of the ADVIA Centaur® Syphilis CLIA assay was 99.7% (95% CI: 98.5-100), and the specificity was 99.4% (95% CI: 98.7-99.7). The ROC area values were 0.996 (95% CI: 0.992-0.999), and both the PPV and NPV values were above 98% (PPV 98.1%, 95% CI: 96.1-99.2; NPV 99.9%, 95% CI: 99.5-100).CONCLUSIONS: The ADVIA Centaur® Syphilis CLIA assay showed similar performance compared to the SERODIA-TP·PA®. Considering the study is based on QUADAS principles and with a homogeneous population, results are also likely to be generalisable to MSM population but potentially not applicable to lower prevalence populations routinely screened for syphilis. The automated CLIA treponemal assay confirmed to be accurate and appropriate for routine initial syphilis screening, i.e. when the reverse testing algorithm is applied.
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- Shephard, Mark, et al.
(författare)
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Independent clinic-based evaluation of point-of-care testing for the screening of Chlamydia trachomatis, Neisseria gonorrhoea and Trichomonas vaginalis in women-at-risk in Australia, Guatemala, Morocco, and South Africa
- 2024
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Ingår i: BMC Infectious Diseases. - : BioMed Central (BMC). - 1471-2334. ; 24:Suppl 1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In 2018, the World Health Organization commenced a multi-country validation study of the Cepheid GeneXpert for a range of molecular-based point-of-care (POC) tests in primary care settings. One study arm focused on the evaluation of POC tests for screening 'women at risk' for chlamydia (CT), gonorrhoea (NG) and trichomonas (TV) in four countries - Australia, Guatemala, Morocco and South Africa.METHODS: Study participants completed a pre-test questionnaire which included demographics, clinical information and general questions on POC testing (POCT). Two vaginal swab samples (either self-collected or clinician collected) from each patient were tested on the GeneXpert at the POC and at a reference laboratory using quality-assured nucleic acid amplification tests (NAATs).RESULTS: One thousand three hundred and eighty-three women were enrolled: 58.6% from South Africa, 29.2% from Morocco, 6.2% from Guatemala, and 6.0% from Australia. 1296 samples for CT/NG and 1380 samples for TV were tested by the GeneXpert and the reference NAAT. The rate of unsuccessful tests on the GeneXpert was 1.9% for CT, 1.5% for NG and 0.96% for TV. The prevalence of CT, NG and TV was 31%, 13% and 23%, respectively. 1.5% of samples were positive for all three infections; 7.8% were positive for CT and NG; 2.4% were positive for NG and TV; and 7.3% were positive for CT and TV. Compared to reference NAATs, pooled estimates of sensitivity for the GeneXpert tests were 83.7% (95% confidence intervals 69.2-92.1) for CT, 90.5% (85.1-94.1) for NG and 64.7% (58.1-70.7) for TV (although estimates varied considerably between countries). Estimates for specificity were ≥96% for all three tests both within- and between-countries. Pooled positive and negative likelihood ratios were: 32.7 ([CI] 21.2-50.5) and 0.17 (0.08-0.33) for CT; 95.3 (36.9-245.7) and 0.10 (0.06-0.15) for NG; and 56.5 (31.6-101.1) and 0.35 (0.27-0.47) for TV.CONCLUSION: This multi-country evaluation is the first of its kind world-wide. Positive likelihood ratios, as well as specificity estimates, indicate the GeneXpert POC test results for CT, NG and TV were clinically acceptable for ruling in the presence of disease. However, negative likelihood ratios and variable sensitivity estimates from this study were poorer than expected for ruling out these infections, particularly for TV.TRIAL REGISTRATION: Ethics approval to conduct the ProSPeRo study was granted by the WHO Ethics Review Committee, as well as local ethics committees from all participating countries.
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